STW Sustainable/ NZEB Design Presentation - Nov 2019

Scott Tallon Walker ArchitectsNoel Hughes | 27th Nov 2019
nZEB (Part II)
Implementation of the New Standards
“Sustainable development is the pathway to the
future we want for all. It offers a framework to
generate economic growth, achieve social justice,
exercise environmental stewardship and strengthen
governance.”
- Ban Ki-moon

nZEB │ Introduction
Introduction│ Content
Section 1│Legislation
• Overview of new TGD Part L (Domestic + Non-Domestic)
• Overview of new TGD Part F
• Legislative impact of future Renovation Works
Section 3│Sustainable Design Concepts
• Introduction to the ‘Fabric First’ Design Approach
• Introduction to basic Low Energy Design Concepts
• Introduction to Passive Energy Strategies
Section 4│Construction Stage
• Overview of the importance of Workmanship
• Overview of Site Implementation
Section 5│Renewables + Technologies
• Overview of PV Panels and Heat Pump technologies
• Introduction of new Renewable Technologies
• Introduction of new Building Controls + Systems
Section 6│ Frequently Asked Questions
• Overview of frequently asked NZEB questions
• nZEB impacts on the principle building elements (Wall, Roofs, Floors)
• Mitigating the risk of Thermal Bridging + Mould Growth
Section 2│Design Process
• Impact on nZEB on typical RIBA Work Stages
• Impact of Energy Reduction Process at key Construction Stages
• Additional Design Team Tasks, New Responsibilities + Contract Risks
nZEB
01
Legislation
02
Design
Process
03
Sustainable
Design
Concepts
04
Construction
Stage
05
Renewable
+
Technologie
s
06
Frequently
Asked
Questions

nZEB Definition [EPBD (2010/31/EU) Article 2]
‘Nearly Zero-energy Building’ means a building that has a very high energy performance, as
determined in accordance with Annex I [of the EPBD].
The nearly zero or very low amount of energy required should be covered to a very significant
extent by energy from renewable sources, including energy from renewable sources produced on-
site or nearby;
Introduction│ EPBD

Energy Performance of
Buildings Directive (EPBD)
The objective of the Directive is to
set a framework for the
application of minimum
requirements for the energy
performance of new buildings
across the EU.
• Member states to ensure that
all new buildings are “Nearly
Zero Energy Buildings” by 31st
Dec 2020
• Member states to ensure that
all new buildings owned and
occupied by Public Authorities
are `Nearly Zero Energy
Buildings’ after 31st Dec 2018
• Major Renovations to be at Cost
Optimal Level in Building Codes

EPBD Public Deadline
European Energy Performance of
Buildings Directive (2010/31/EU)
Article 09 states:
• all new buildings which
are owned or occupied by
Public Authorities need to be
nZEB the 31st December 2018
Note: “Occupied” is the
keyword, as it implies that
a premises must have a
valid nZEB Certificate of
Completion by 31/12/2018
for a public tenant to
occupy a new premises
without being in violation
of the EPBD and face fines

EPBD + Renovation Works
Article 02 states:
• the total cost of the renovation
relating to the building
envelope or the technical
building systems is higher than
25 % of the value of the
building, excluding the value of
the land upon which the
building is situated;
or
• more than 25 % of the surface
of the building envelope
undergoes renovation;

National Implementation
Article 4 states:
• Member States shall take the
necessary measures to ensure
that minimum energy
performance requirements for
buildings or building units are
set with a view to achieving
cost-optimal levels.
In Ireland and the UK, this is the
Part L energy building regulation.
Ireland UK
Introduction│ Part L

Section 1│Legislation
Contents
• nZEB and TGD Part L
• Overview of TGD Part L Non-Domestic - New Build
• Overview of TGD Part L Non-Domestic - Renovation
• Overview of TGD Part L Domestic - New Build
• Overview of TGD Part L Domestic - Renovation
• Overview of TGD Part F
• Part L: Design Implications

nZEB │ 01: Legislation
Section 1│nZEB and Part L
Part L - Non Domestic 2017
• Comes into effect: 1st January 2019
• Improvement in performance in the
order of 60% over TGD Part L (2008)
• Improved Fabric Specification
• Renewable Energy Ratio of 20%
10% for High Performance Building
Fabric Structures
Part L - Domestic 2018
• Comes into effect: 1st April 2019
• Improvement in performance in the
order of 25% over TGD Part L (2011)
• Improved Fabric Specification
• Renewable Energy Ratio of 20% only
Part F - 2019
• Maximum Air Permeability 5 m³/h.m²
• Mechanical Ventilation for all Air
Permeability results below 3 m³/h.m²

TGD Part L - Non
Domestic (2017)
• Renewables requirement will be
included as Renewable Energy
Ratio (RER) = 20%
• Represents a very significant
level of energy provision from
renewable energy technologies
Regulation L5 (b)
• “Where the MPEPC of 1.0 and
MPCPC of 1.15 is achieved an
RER of 0.20”
• “Where the MPEPC of 0.9 and
MPCPC of 1.04 is achieved an
RER of 0.10”
• Renewable energy sources
include Photovoltaic, Heat
Pumps (Air source and ground
source), Biomass, Solar
Thermal ,Primary Energy
Savings from Combined Heat
and Power (CHP), Renewable
district heating
Section 1│Part L + Renewables

• Par 1.5.5: Commissioning
The key elements of a
commissioning plan, identifying
the systems that need to be
tested and the tests that will be
carried out and should be
developed at the design stage
• Par 1.5.4.2: Airtightness Testing
Air pressure testing should be
carried on all development sites
to show attainment of backstop
value of 5 m³/(hr.m²). The tests
should be carried out by a
person certified by an
independent third party
• Par 1.5.6.1: Ductwork Leakage
Leakage testing should be
carried out on systems served
by fans with a design flow
greater than 1m³/s
Other Part L (2017)
Requirements
• Lighting should meet minimum
recommended standards for
efficacy and controls
• Par 1.3.6: Overheating
Assessment
The designer should specify
what the indoor comfort
specification and perform an
overheating assessment to
ensure overheating is avoided
BMS
• Boilers over 100kW to have
BMS controls and AC systems
over 200m² to have BMS
controls
• A full BMS system will provide
full zoned time control and
weather compensation where
applicable, frost protection or
night set-back optimization and
monitoring and targeting
Section 1│Part L Non-Domestic – New Build

Section 1│Part L Non-Domestic – New Build
Reference Building
Values
Conservation of Fuel
and Energy –other than
Dwellings 2008
and Energy – other than
Dwellings 2017
Improvement
U- Values: Walls 0.37 W/m²K 0.18 W/m²K 33%
U- Values: Roof 0.25 W/m²K 0.15 W/m²K 6%
U- Values: Floor 0.37 W/m²K 0.15 W/m²K 40%
U- Values: Windows 2.20 W/m²K 1.40 W/m²K 36%
Glazing Solar
Transmittance
0.72 0.4
Thermal Bridging Add 16% to fabric heat loss
Y-Value = Actual Length of Key
Junctions x Advanced psi value
-
Air Permeability 10 m³/(hr.m²)
5 m³/(hr.m²) Floor Area ≤250m²
3 m³/(hr.m²) Floor Area ≥250m²
50%
70%
Opening Areas
Offices and Shops - Windows
and Pedestrian Doors are
40% of the total area of
Exposed Walls
Offices and Shops - Windows
and Pedestrian Doors are
40% of the total area of
Exposed Walls
-
Renewable Energy Ratio None
20%
of Primary Energy Use
-
Limitation of Overheating BRE Report No 364 CIBSE TM 59 -

Par 2.3.4
The following improvements are
normally considered to be cost
optimal and will typically be
economically feasible when more
than 25% of the surface area of a
building is being upgraded
• Upgrading heating systems
more than 15 years old
• Upgrading cooling and
ventilation systems more than
15 years old
• Upgrading general lighting
systems that have an average
lamp efficacy of less than 40
lamp lumens per circuit-watt
and that serves greater than
100m²
TGD Part L (2017) - Major
Renovations
Par 2.3.2
When calculating the proportion of
surface area undergoing
renovation the area of the whole
building external envelope should
be taken into account including
i.e. external walls, roofs, floors,
windows, doors , and roof
windows and lights
Works to the surface area of the
building include the following:
• Cladding the external surface of
the element
• Drylining the internal surface of
an element
• Replacing windows
• Stripping down the element to
expose the basic structural
components and then
rebuilding to achieve all the
necessary performance
requirements.
Building Type
Primary
Energy
BER
kWh/yr/m²
Air Conditioned Retail 338 E1
Natural Ventilated Offices
and Other Buildings
124 B3
Air Conditioned Office 180 C3
Air Conditioned Hotel 342 E2
Schools 60 B1
Other Air Conditioned
Buildings
338 E2
Other Naturally Ventilated
Buildings
124 B3
Major Renovation - Cost Optimal Level
Section 1│Part L Non-Domestic – Renovation

Section 1│Part L Domestic – New Build
Reference Building
Values
and Energy - Dwellings
2011
2018
Improvement
U- Values: Walls 0.21 W/m²K 0.18 W/m²K 14%
U- Values: Roof 0.16 W/m²K 0.16 W/m²K -
U- Values: Floor 0.21 W/m²K 0.18 W/m²K 14%
U- Values: Windows 1.60 W/m²K 1.40 W/m²K 12.5%
Glazing Solar
Transmittance
DEAP Table 6a 0.6
Thermal Bridging
Default = 0.15 W/m2K
ACD = 0.08 W/m2K
ACD = 0.08 W/m2K
(0.10 W/m2K Recommended Maximum)
0.05 W/m2K in Reference Buildings
-
5 m³/(hr.m²) Maximum
≥3 m³/(hr.m²) Mechanical
Ventilation required
28.5%
Air Pressure Testing A Proportion of Dwellings All -
Renewable Energy Ratio
10 kWh/m²/yr to heating or
4 kWh/m²/yr to electrical
20%
-
Limitation of Overheating - CIBSE TM 59 -
However, the foregoing document may continue to be used
in the case of dwellings:
• where the works, material alteration, change of use or major
renovation commences or takes place, as the case may be,
on or before 31st October 2019,
or
• Where planning approval or permission has been applied
for on or before 31st October 2019 and substantial work
has been completed by 31st October 2020

Section 1│Part L Domestic - Renovation
Major Renovation
Providing that where more than 25% of the surface area of
the building envelope undergoes renovation the energy
performance of the whole building should be improved to
Cost Optimal level in so far as this is technically, functionally
and economically feasible. Guidance is given in section 2.3.
2.3.5 Works to the surface area for
which it is technically,
functionally and economically
feasible to improve the energy
performance of the whole
building to cost optimal level
include the following:
- Cladding the external surface
of the wall
- Drylining the internal surface
of a wall
2.3.6 Painting, plastering, rendering,
re-slating or re-tiling are not
considered a major renovation.
Par 2.3: Major Renovation
2.3.1 Where more than 25% of the
surface area of the dwelling
envelope undergoes the energy
performance of the whole
building should be improved to
Cost Optimal level in so far as
this is technically, functionally
and economically feasible.
2.3.2 The cost optimal performance
level to be achieved is 125
kWh/m²/yr when calculated in
DEAP
Primary
Energy
BER
kWh/yr/m²
Major Renovation
Upgrade Standard
125 B3

Reference Building
Values
2011
2018
Improvement
U- Values: Walls
Cavity = 0.55 W/m²K
Other = 0.35 W/m²K
Cavity = 0.55 W/m²K
Other = 0.35 W/m²K
-
U- Values: Roof
to Ceiling = 0.16 W/m²K
to Slope = 0.25 W/m²K
to Ceiling = 0.16 W/m²K
to Slope = 0.25 W/m²K
-
U- Values: Floor 0.45 W/m²K 0.45 W/m²K -
U- Values: Windows 1.60 W/m²K 1.40 W/m²K 12.5%
Glazing Solar
Transmittance
DEAP Table 6a 0.6
Thermal Bridging
ACD = 0.08 W/m2K
ACD = 0.08 W/m2K
(0.10 W/m2K Recommended Maximum)
0.05 W/m2K in Reference Buildings
5 m³/(hr.m²) Maximum
≥3 m³/(hr.m²) Mechanical
Ventilation required
Air Pressure Testing A Proportion of Dwellings All
Renewable Energy Ratio
10 kWh/m²/yr to heating or
4 kWh/m²/yr to electrical
20%
Limitation of Overheating - CIBSE TM 59
Major Renovation

Major Renovation
2.1.4 Air Permeability
2.1.4.2 For material alterations or material change of use infiltration of cold
outside air should be limited by reducing unintentional air paths as far as is
practicable. Measures to ensure this include: -
a) sealing the void between dry-lining and masonry walls at the edges of
openings such as windows and doors, and at the junctions with walls, floors
and ceilings (e.g. by continuous bands of bonding plaster or battens);
b) sealing vapour control membranes in timber-frame constructions;
c) fitting draught-stripping in the frames of openable elements of windows,
doors and rooflights;
d) sealing around loft hatches;
e) ensuring boxing for concealed services is sealed at floor and ceiling levels
and sealing piped services where they penetrate or project into hollow
construction or voids.

Buildings other than Dwellings
• General ventilation rate of 10l/s
per occupant for buildings is
appropriate where there are no
significant pollutant levels.
• 1.3.2.2 For single-sided offices
of depths of less than 6m and
cross ventilated offices of depth
less than 12m ventilation rates
should be in accordance with
Table 4.
• 1.3.2.4 For other office
buildings adequate provision
using natural ventilation may
be achieved by following the
guidance on the design of
natural ventilation systems in
CIBSE Application Manual
AM10: Natural ventilation in
non-domestic buildings.
TGD Part F (2019)
• Maximum air permeability of
5m³/(h.m²) at 50pa for all new
buildings
Dwellings
• Natural ventilation acceptable for
homes with an airtightness
between 3m³/(h.m²) and
5m³/(h.m²)
• Mechanical ventilation required
for homes with an airtightness
lower than 5m³/(h.m²)
Question
How does a developer who has
specified natural ventilation at design
stage, ensure their project then falls
into the narrow airtightness margin
between 3m³/(h.m²) and 5m³/(h.m²)
once on site.
Section 1│Part F – Ventilation

Section 1│Part L - Design Implications
Old Construction Process
1) Insulation (limited)
nZEB Process
1) High level of Insulation
2008 2017/2019
(nZEB)

nZEB Process
High Levels
of insulation
Must be better that
backstop values in
Part L Table 1

2) No review of Thermal
Bridges
nZEB Process
2) No Thermal Bridges
Part L (2017) Domestic
Maximum value = 0.1 m²K/W
DEAP Default value = 0.08 m²K/W
Target should be 0.05 m²K/W
or lower

Bridges
nZEB Process
3) Airtightness Layer
Part F (2019)
Maximum air permeability of
5m³/(h.m²) at 50pa
Review
Good Practice Guide 268: Energy
efficient ventilation in dwellings:
A guide for specifiers, 2006

Bridges
3) Glazing (limited review
of overheating)
nZEB Process
4) Glazing + Solar Study
Review
• CIBSE SLL Lighting Guide 10:
Daylighting and window design

Bridges
of overheating)
nZEB Process
5) Shading Systems
Review
• CIBSE TM 37: Designing for
improved solar shading control
• CIBSE TM52: The Limits of Thermal
Comfort: Avoiding Overheating in
European Buildings
• CIBSE TM 59: Design Methodology
for the assessment of overheating
risk in homes
• BSRIA Guide BG 8/2004 Free
Cooling Systems;

Bridges
of overheating)
4) High Energy Heating
and Cooling systems
nZEB Process
5) Shading Systems
6) Renewables
nZEB energy targets require
for 20% of a building’s final
energy demands to be
provided by onsite renewables
High temperature heating systems and
HVAC cooling systems consume a large
amount if energy

Bridges
of overheating)
and Cooling systems
nZEB Process
5) Shading Systems
6) Renewables
7) Low Energy Heating
and Cooling systems
Review
• CIBSE Guide AM
13 Mixed Mode
Ventilation; CIBSE
2000
• CIBSE Manual AM
12: Combined Heat
and Power in
Buildings, CIBSE
2013

Bridges
of overheating)
and Cooling systems
5) Large Energy Losses
nZEB Process
5) Shading Systems
6) Renewables
7) Low Energy Heating
and Cooling systems
8) Exclusion of Heating
or Cooling Systems

Section 2│Design Process
Contents
• RIBA Work Stage
• Stage 0: Strategic Definition
• Stage 1: Preparation & Brief
• Stage 2: Concept Design
• Stage 3: Developed Design
• Stage 4: Technical Design
• Stage 5: Construction
• Stage 6: Handover & Close Out
• Stage 7: In Use

nZEB │ 02: Design Process
Section 2│RIBA Work Stages
• Stage 0: Strategic Definition
• Strategic Brief
• Scope of Services
• Fees
• Stage 1: Preparation & Brief
• Initial Project Brief
• Feasibility Studies
• Stage 2: Concept Design
• Concept Design
• Building Services Design
• Preliminary Cost Information
• Final Project Brief
• Stage 3: Developed Design
• Coordinated architectural,
structural and building
services design
• Updated Cost Information.
• Planning Application
• Fire/ DAC Applications
• Stage 4: Technical Design
• Tender Documentation
• Safety Matrix (PSDP/ PSCS)
• Stage 5: Construction
• Construction Drawings
• Schedules
• Stage 6: Handover & Close Out
• Safety File
• ‘As build’ Drawings
• Commissioning Data
• User Manuals
• Stage 7: In Use
• Ongoing Client Feedback
• Maintenance or Operational
Assessments
RIBA Work Stages
The RIBA Plan of Work organises the process of briefing, designing,
constructing and operating building projects into eight stages and details
the tasks and outputs required at each stage.

RIBA Plan of Works

The RIBA Plan of Work details specific
Sustainability Checkpoint tasks
RIBA Plan of Works

And suggested Support Tasks for various
Work Stages
RIBA Plan of Works

And suggested Support Tasks for various
Work Stages
RIBA Plan of Works
Be aware that these items do not relate to
NZEB or Irish Regs. While they are helpful
they do not address Part L or BCAR
requirements.

RIBA Work Stage 0
RIBA Sustainability Checkpoint 0
• Ensure that a strategic
sustainability review of client
needs and potential sites has
been carried out, including reuse
of existing facilities, building
components or materials
Section 2│RIBA Work Stage 0
Strategic
Definition
NZEB comments
• By asking the right questions,
the consultants, in collaboration
with the client, can properly
define the scope for a project,
and the preparation and briefing
process can then begin.
Remember
Major Renovation under Part L
applies to where more than 25%
of the surface area of the
building envelope undergoes
renovation (works to walls,
windows and roof)
Then the energy performance of
the whole building should be
improved to a BER B2

RIBA Work Stage 1
• Confirm that formal sustainability
targets are stated in the Initial
Project Brief.
• Confirm that environmental
requirements, building lifespan
and future climate parameters are
stated in the Initial Project Brief.
• Have early stage consultations,
surveys or monitoring been
undertaken as necessary to meet
sustainability criteria or
assessment procedures?
• Check that the principles of the
Handover Strategy and post-
completion services are included
in each party’s Schedule of
Services.
• Confirm that the Site Waste
Management Plan has been
implemented.
Preparation
and Brief
NZEB comments
• Brief development is a key part
of all sustainable design goals.
Understand exactly what the
clients wants/ needs to avoid
designing in unneeded building
systems
• NZEB is building regulations
requirements and is required for
all new building projects.
However the energy strategy
needs to be design to a clients’
project and budget
requirements
• Part L (2017): Non Domestic
allows for on 10% renewable
requirement instead of the
typical 20% for schemes with a
high performing building fabric.
This is something to be
discussed with the client as the
savings on renewables may
offset the additional expenditure
on the facade

RIBA Work Stage 2
• Confirm that formal sustainability
pre-assessment and identification
of key areas of design focus have
been undertaken and that any
deviation from the Sustainability
Aspirations has been reported and
agreed.
• Has the initial Building Regulations
Part L assessment been carried
out?
• Have ‘plain English’ descriptions of
internal environmental conditions
and seasonal control strategies and
systems been prepared?
• Has the environmental impact of
key materials and the Construction
Strategy been checked?
• Has resilience to future changes in
climate been considered?
Concept
Design
NZEB comments
• Concept Design is the most
crucial stage when it comes to
low energy/ sustainable design
schemes. The majority of key
sustainability related decisions
are made during this project
stage
• When appointing the initial
design team, consideration
must be give to who will
undertake the initial daylighting
and energy analysis of the
sketch schemes.
• Consideration should be given
at this stage if any other
sustainable rating systems is to
be followed

NZEB comments
• Initial design decision made at the Concept Stage will have significant impact
on the final energy use of any project
• 60% of a buildings energy use is ‘locked into’ during the Concept Stage
• Site Location
• Buildings Massing
• Glazing Ratio and Shading Strategy
• Additionally a projects renewable strategy are broadly agreed during the
Concept Design stage as well
5%
10%
10%
20%
15%
15%
5%
20% Site Location + Wind Flow
Building's Massing
Builing's Solar Access
Glazing + Daylighting
Ventilation Strategy
Building Systems
Water Usage
Renewables
Concept
Design

Concept
Design
NZEB comments
• An Iterative design methodology based on a cyclic process of concept
design, followed by building analyses, to develop/ refine the scheme needs to
be adopted in order to efficiently progress NZEB compliant projects
• This approach requires addition time and resources are the beginning of a
project. However this approach has the potential to save significant project
resources and client expense later on in the project
Concept
Design
Daylighting
Analysis
Basic Energy
Analysis
Cost
Optimisation
Design Team
Review

RIBA Work Stage 3
• Has a full formal sustainability
assessment been carried out?
• Have an interim Building
Regulations Part L assessment and
a design stage carbon/energy
declaration been undertaken?
• Has the design been reviewed to
identify opportunities to reduce
resource use and waste and the
results recorded in the Site Waste
Management Plan?
Developed
Design
NZEB comments
• By asking the right questions,
the consultants, in collaboration
with the client, can properly
define the scope for a project,
and the preparation and briefing
process can then begin.

Developed
Design
NZEB comments
• Similar to the Concept Stage, a iterative design process should be adopted
during the Developed Design stage, albeit a more extensive assessment
process
• It is important to consider the cost impact of a low energy design strategy,
especially the projects renewables. These will typically have a significant
cost impact
Developed
Design
Full Energy
Analysis
Overheating
Analysis
Cost Review
Planning
Review
Design Team
Review

RIBA Work Stage 4
• Is the formal sustainability assessment
substantially complete?
• Have details been audited for airtightness
and continuity of insulation?
• Has the Building Regulations Part L
submission been made and the design
stage carbon/energy declaration been
updated and the future climate impact
assessment prepared?
• Has a non-technical user guide been
drafted and have the format and content
of the Part L log book been agreed?
• Has all outstanding design stage
sustainability assessment information
been submitted?
• Are building Handover Strategy and
monitoring technologies specified?
• Have the implications of changes to the
specification or design been reviewed
against agreed sustainability criteria?
• Has compliance of agreed sustainability
criteria for contributions by specialist
subcontractors been demonstrated?
Technical
Design
NZEB comments
• The preparation of tender
documentation represents the
last chance for the Design
Team to review the NZEB
aspects of a scheme before
construction begins
• Attention must be given to how
U-Value requirements, Thermal
Bridge requirements,
Airtightness minimums and
strategies for renewables and
building systems
• Contract documents must
highlight workmanship and
quality benchmark strategies to
ensure works are completed to
BCAR requirements
• Remember NZEB/ Part L are
requirements of Building
Regulations and not client
aspirations. They must be
adhered too.

Technical
Design
NZEB comments
• The method of how new NZEB specific information is included in the Tender
Package is dependant on form of contract
• It is key that the contractor is given the adequate information on all assumed
U-Values, Psi-Values etc which were used in the draft NEAP/ DEAP
calculations
NZEB at
Tender
Stage
Typical Tender
Documents
Thermal Bridging
Details
Element U-Values
Airtightness
Requirement
NEAP/ DEAP Calculations

RIBA Work Stage 5
• Has the design stage sustainability
assessment been certified?
• Have sustainability procedures
been developed with the contractor
and included in the Construction
Strategy?
• Has the detailed commissioning
and Handover Strategy programme
been reviewed?
• Confirm that the contractor’s
interim testing and monitoring of
construction has been reviewed
and observed, particularly in
relation to airtightness and
continuity of insulation.
• is the non-technical user guide
complete and the aftercare service
set up?
• Has the ‘As-constructed’
Information been issued for post-
construction sustainability
certification?
Construction
NZEB comments
• NZEB does not introduces any
additional new requirements
during the Construction stage
• However it does place a high
dependency of project
workmanship and this should
be considered under any BCAR
inspections
• Be aware that any changes to
the thermal envelope or thermal
bridging detail will need to be
assessed. This will add
additional cost and time delays
to a project
• €400 + 2 day for 2D
details
• €600 + 5 days for 3D
details (all details that
containing steel or
aluminium junctions need
to be modelled in 3D)

RIBA Work Stage 6
• Has assistance with the collation of
post-completion information for
final sustainability certification been
provided?
Handover
and Close Out
NZEB comments
• All completed new projects
require a completed BER
certificate. This is based on the
‘as build’ NEAP/ DEAP values

RIBA Work Stage 7
• Has observation of the building
operation in use and assistance
with fine tuning and guidance for
occupants been undertaken?
• Has the energy/carbon
performance been declared?
In Use
NZEB comments
• NZEB does not relate to ‘In
Use’, however other
sustainable rating systems such
as LEED, WELL and the living
Building Challenge requires
onsite assessment

nZEB │ 03: Sustainable Design Concepts
Section 3│Sustainable Design Concepts
Contents
• Impact of Design Decisions
• Site Location + Micro Climate
• Orientation + Form
• Solar Access + Thermal Mass
• Glazing Ratio + Daylighting
• Overheating + Shading
• Ventilation
• Building Systems
• Water Usage
• Onsite Renewables
• Building Usage + Occupants

Concept Design
Developed Design
Technical Design
Section 3│Impact of Design Decisions
5
10
10
20
15
15
5
20
Site Location + Wind Flow
Building's Massing
Builing's Solar Access
Glazing + Daylighting
Ventilation Strategy
Services + Building
Systems
Water Usage
Renewables
The Importance of Early Design
Basics: Sustainability starts in sketch
design, not when you get onsite
About 25% of a buildings final energy use
is decided in the Concept Stage, with a
further 35% in the Developed Design
stage.
This means that 60% of a buildings final
energy usage is ‘locked in’ before planning
drawings are submitted.
CONCEPT DESIGN DEVELOPED DESIGN TECHNICAL DESIGN
Site Location + Wind Flow Glazing Ratio
Services + Building
Systems
Building’s Massing Daylighting + Shading Water Usage
Building’s Solar Access Building Ventilation Renewable

Orientation
Basics: Sun rises in the East and sets
in the West
Obvious as it may seem, it is important to
remember that during winter the sun
actually rises south of east and in the
summer rises north of east.
So in the summer north facing facades will
very briefly be exposed to the sun.
It is important to consider the suns path
when design areas which may develop
micro-climates: sunken or sheltered area,
sun rooms + gardens and atrium spaces.
It is also important to consider the potential
impacts of glare from the low winter sun
when developing BREEAM and LEED
projects.
Section 3│ Site Location + Local Micro-Climate

Orientation
Basics: Sun rises in the East and sets in the West
It is important to consider the suns path when design areas which may develop
micro-climates: sunken or sheltered area, sun rooms + gardens and atrium
spaces.
Form Optimisation
Basics: Compact building use less energy
The greater the surface areas of a building envelope, the more energy it will
lose through fabric loss, thermal bridges and air permeability. In the winter a
single storey home could use up to 25% more energy compare to a two storey
home of the same floor area
Section 3│Concept Design: Orientation + Form

Solar Access
Basics: Southern light is the strongest and rises highest in the sky.
East or light is not as strong but is lower, especially during winter.
As designers there are a range of solutions for maximising sunlight while
preventing unwanted solar gains
Thermal Mass
High thermal mass building elements will absorb heat slowly and store it. The
store heat will then be released slowly into the building
In buildings with high thermal mass, the highest indoor temperatures will occur
in the early hours of the morning, typically a number of hours after the highest
outdoor temperatures have been reached.. This slow response time is know as
the ‘Thermal Flywheel Effect’
Section 3│Concept Design: Solar Access + Thermal Mass

It is important that Daylighting Analysis is
incorporated into the Concept Design
Stage. This will allow for the optimisation
of any design strategy before the façade is
finalised prior to a planning application
Section 3│Developed Design: Glazing Ratio + Daylighting

Section 3│Developed Design: Overheating + Shading
Basics: Southern solar shading should be horizontal due to high angle of the
summer sun.
East or West shading should be vertical to shade against the low
angle of sun.
External shading devices perform better than internal methods as they
completely prevent the sun’s rays from entering the building. Internal blinds,
while preventing solar glare, will not prevent overheating

Section 3│Developed Design: Ventilation
Natural Ventilation
Note: As most natural ventilations are wind or external air pressure driven,
on still days they will either operate at a greatly reduced
performance or be completely ineffectual.
There are two main forces that underpin natural ventilation systems, they are
Wind and thermal Buoyancy.
In Ireland and the UK, external wind conditions is the most dominating deciding
factor in the daily levels of natural ventilation for most buildings. Wind meeting a
building creates a pressure difference between its windward and leeward faces,
and this drives ventilation. Therefore if it is not windy there is little to no
ventilation
Mechanical Ventilation
When it comes to low energy design,
mechanical ventilation is a two edged sword.
HVAC systems are extremely energy heavy,
however MVHR systems can prove to be an
excellent means of providing low energy space
heating.
MVHR systems will count towards the 20%
Renewable Energy Ratio (RER)

Single-Sided Ventilation
For spaces that have only access to a
single external façade, a maximum are of
6m can be effectively ventilated.
Allow for an opening area of at least 5% of
the floor area to be ventilated.
Cross Ventilation
Cross ventilation relies on the pressure
difference between the windward and
leeward facades. It is effective for spaces
whos depth is no greater the 5 times the
ope height. Again allow for an opening
area of at least 5% of the floor area to be
ventilated.
Stack Ventilation
Stack Ventilation relies on buoyancy of air
and requires a a temperature difference of
over 2 ˚C to be inside and outside.
• Rule-of-Thumb:
In Ireland/UK all year around natural
ground floor ventilation will need a
five-storey high stack
Single –Sided Ventilation
Stack Ventilation
Cross Ventilation

Mechanical Heat Recovery
Through the use of a mechanical
ventilation system with a heat recovery
unit (MVHR), it is possible to extract heat
from the exhaust air and use it to warm
incoming fresh air.
Such systems need a well insulated
building with a airtight building envelope
Note: Unless a building achieves an
air tightness of a minimum of 3
Air Changes per Hour – MVHR
will not be cost effective
At higher ACH rates a MVHR
unit will use more energy to run
it’s air pump that any energy
recovery from the exhaust air

No Night Time Purging Night Time Purging Night Time Purging
Thanks to the high energy performance in
nZEB. And combined with an increase in
airtightness levels (1.0 ACH should be
achievable, the minimum Passive House
requirement is 0.6 ACH) will potentially
increase the risk of overheating.
A cost effective means of cooling a building
is night purging.
This can either be mechanical or natural
ventilation system and can be a smart
system controlled by a BMS or a simple as
open window at night.
It is a highly efficient, simple and cheap
method of cooling a structure and reducing
the risk of overheating

Section 3│Technical Design: Building Systems
BEMS
The energy-saving benefits of Building Energy Management Systems are well
known. BEMS systems can improve comfort levels in buildings, enable better
maintenance and deliver financial savings of up to 20%. This, in turn, reduces
impact on the environment caused by emissions of greenhouse gases – giving
both financial and environmental benefits. The savings created through using a
BEMS can be substantial and recur year after year.
Smart Metres
Smart electricity meters can monitor electricity use in various areas such as
lighting, compressed air or air conditioning. Using the information, graphs of
electricity usage can be plotted which allows management to formulate the
optimal electricity usage plan. Once a norm is established, such as electricity
usage per bed-night, the BEMS can be programmed to alert when energy usage
drifts away from the norm.
Similarly, fuel meters, water meters,
heat meters and so on, can be
monitored and analysed against
similar parameters. The data can
also be used to see the effect of
operational changes or energy
saving investments.

Section 3│Technical Design: Water Usage
Due to the new Part L requirements, space
heating is no longer the dominant energy
demand for domestic projects.
Domestic Water is not the principle area
of energy consumption
Domestic Water Usage
• Average Irish usage is 150 litres per
person per day
• 60% of water use in the home is within
the bathroom
• 50% associated with shower’s and
WC’s
• Research by EST in the UK on national
water use per annum:
• 840 billion litres of water used for
showers
• £2.3 billion spent on heating water for
showers
• 740 billion litres of water used to flush
WC’s
• Dishwashers and washing machines
uses 360+ billon litres of water

Section 3│Technical Design: Onsite Renewables
The Renewable Energy Ratio (RER) states that “20% of its energy provided
from onsite or nearby Renewables”. The term ‘nearby renewables’ does not
apply to green energy bought of a local grid but to allow for centralised systems
such as CHP for use in campus or large scale developments.
Section 1.2.4
The use of centralised renewable energy sources contributing to a heat
distribution system serving all new building units other than dwellings on a
campus or part of a development, may prove to be more practicable than
providing separate renewable energy for each building individually.
This means that the potential for renewables technologies must be allowed for
in detailed design drawings. As large arrays of solar panels, banks of heat
pumps or micro wind turbines will all require planning approval.

Section 3│Building Usage + Occupants
Keep it Simple
Building occupants will ignore or override complex controls and systems. And
over time they will forget how to effectively operate a system, typical running
and energy saving or adding to ‘wear and tear’.
People feel more comfortable when they have control over their environment.
So any design must be robust, intuitive and simple.
Reduce Energy demand through Design
The building sector accounts for about 40% of total energy consumption and
38% of the CO2 emissions in the US. And about 27% of the total emissions in
UK are attributed to the buildings
This means that the Design Team is best placed to reduce the initial building
energy requirements through clever space planning and an understanding of
how building services/ systems will be used

Section 4│Construction Stage
Contents
• Workmanship
• Site Compliance
• Setout of Services

nZEB │ 04: Construction Stage
On-Site Quality Control
The importance of commitment from on-
site contractors to the nZEB process
cannot be understated.
Contractors who have successfully
completed low-energy projects have
recommended the used of continuous
onsite inspect and the appointment of an
onsite champion. Areas of concern would
be:
• Airtightness
• Continuity of Insulation
• Integrity of vapour control layers
Suitable clause will need to any contract to
ensure onsite construction quality (with
appropriate awards and damages) and key
dates for inspection will need to be
included in the construction programme
Be prepared for “I have been building
for XX years” arguments
Section 4│ Workmanship

Methods of ensuring On-site
Compliance
• Adopt Design Responsibility Mapping
when key tasks are assign to a
dedicated member of the on-site team
(i.e.. airtightness champion)
• Benchmarking of first installation of key
junctions
• Contract Clauses for Quality Metrics
• Contractor is contractually responsible
for NZEB coordination
• Focus is given to service penetration
coordination
• Engage suppliers who will inspect
workmanship
• Centrally track issues and defects. As
well as remedially actions and items
closed out
• Have workmen send pictures to a
database of completed items. Improves
workmanships and acts as BCAR
evidence
Section 4│ Site Compliance

Setout of Services
In order to meet the new TGD Part L - Non-
Domestic (2017), all primary service
distribution routes will need to be insulated,
as well as many secondary services.
For example the heat gains in a large
building from uninsulated domestic hot
water can be substantial, particularly during
summer months and contribute to
overheating. If a ø32mm pipe needs 25mm
insulation, the resulting ø82mm pipe may
increase the width requirements of service
zones and studwork
The setout of pop-up positions to floor slab
and penetrations to external walls will all
need to take account of the requirements
for additional insulation
See Section 5 for further detail
Section 4│ Construction Advice

Section 5│Renewables + Technologies
Contents
• Renewable Energy Ration (RER)
• Site Assessment
• Photovoltaics
• Heat Pumps
• Mechanical Ventilation Heat Recovery (MVHR)
• Combined Heat + Power (CHP)
• Biomass
• Ground Source Heat Pumps
• Domestic Water
• Electrical Controls

nZEB │ 05: Renewables + Technologies
Section 1.2.1
For the purposes of this Section,
“renewable energy technologies” means
technology products or equipment that
supply energy derived from renewable
energy sources, e.g. :
• solar thermal systems,
• on-site solar photovoltaic systems,
• biomass systems,
• systems using biofuels,
• heat pumps,
• combined heat and power,
• aerothermal,
• geothermal,
• hydrothermal,
• wind,
• biomass and biogases;
• and other on-site renewables.
Section 5│ Renewable Energy Ratio (RER)

Appropriate Renewables
In an urban location, most projects will
likely rely on electric based Renewables,
such as PV panels and Heat Pumps
(typical ‘air to water’ or ‘air to air’)
Micro Wind is typical not cost effective in
Ireland and extremely rarely in an urban
location
Note: Micro Wind turbines are designed
to operate at wind speed of 10-12
m/s. Average Irish wind speed at
10m above ground is 4-6m/s (less
in urban environments). The
performance of wind turbines at
these speeds drops significantly
Biofuels maybe be cost effective for rural
development, but is dependant on the
space available for the storage of fuels
Section 5│Site Assessment

A domestic solar PV system consists of a
number of solar panels mounted to your
roof (or in your garden) and connected into
the electrical loads within your building.
The solar panels generate DC (direct
current – like a battery) electricity, which is
then converted in an inverter to AC
(alternating current – like the electricity in
your domestic socket).
Solar PV systems are rated in kilowatts
(kW). A 1kW solar PV system would
require 3 or 4 solar panels on your roof.
On average, a solar PV system can save
between €200-€300 per year on your
domestic electricity bill.
Planning
Generally, you will not need planning
permission for solar panels taking up less
than 50% of the total area of the roof
(approx. a 6-panel system).
Section 5│ Photovoltaics

A solar electric system (PV) is typically
made up of:
• Solar panels on the roof, which
generate DC (direct current – like in a
battery).
• An ‘Inverter’ which converts this to AC
(alternating current – like the electricity
in your house socket).
• Sometimes a battery on larger systems
to save energy for later use.
Solar PV systems generate electricity
during daylight hours only, predominately
around the middle of the day. In Ireland,
around 75% is produced from May to
September. If this electricity is not used in
the home it is exported to the grid.

PV required (kWp) 1.15 1.25 0.90 0 0.60 0
PV required (Panels) 4 5 3 0 1 0

Section 5│ Onyx Solar: Transparent PV Glass

Section 5│ Heat Pumps (Air to Water)

Section 5│Mechanical Ventilation Heat Recovery
Decentralised System
Although MVHR can be installed in any building, there is a rule of thumb that
its use is not justified unless the air permeability of the thermal envelope is at
or below 3 air changes per hour when tested at 50 Pascal (equivalent
approximately to 3 m3/m2.h @ 50 Pa for average dwellings).

Section 5│ Mechanical Ventilation Heat Recovery
Lunos Systems
The LUNOS decentralised system means that we will be
able to retrofit your home with a highly efficient mechanical
ventilation system with heat recovery (MVHR) with
minimum disruption and often at less cost than a more
traditional centralised system.
• No ducting
• Heat recovery units over 90% efficient
• Less than €5 per annum per unit running costs
• Eliminate high humidity and condensation
• Constant fresh air supply without significant loss of heat
• Re-usable washable filters - dishwasher safe

Centralised System
Units can be both indoor or
outdoor. It is important to
consider plant sizing and
primary ventilation duct
routes during the
Developed Design Stage.
Typical Spec:
• Low SFP with energy
saving EC plug fans
• Low noise
• Thermal efficiency up to
93%
• Direct ducting through
the roof
• Side doors for
maintenance works

Section 5│Combined Heat & Power (CHP)
CHP
• Turbine produces electricity form reclaimed Waste Heat
• Electricity generated is 70-80% efficient vs 40% from
the grid
• Only efficient if using the heating system
• Only suitable to building that have a year round heating
demand (hospitals, hotels, swimming pools)

Section 5│Biomass Boilers
Biomass Boiler
• Needs storage space for pellets and buffer heat cylinder
• Needs regular maintenance and ash removal
• Efficiency approx. 85%
• Fuel relatively inexpensive but can be hard to source
• Recommend automated feed systems

Section 5│Ground Source Heat Pumps
Vertical Loops
Most efficient at flow temp of
40-50°C
• Borehole of 150m will
provide approx. 10kW of
heat
• Works well with
underfloor heating and
low temperature systems
• COP = 4
Horizontal Loops
Most efficient at flow temp of
40-50°C
• Requires approx. 50-80m
of pipework for 1kW of
heat
• Works well with
underfloor heating and
low temperature systems
• COP = 4

Section 5│ Reduce Water Use and DHW Demand

Waster Water Heat Recovery
Uses a heat exchanger to recover heat
from warm waste water to pre-heat the cold
water feed to showers or baths
• Energy recovery depends on the
number of units and plumbing systems
that are installed
Section 5│ Domestic Water Heat Recovery

Section 5│ Wireless Electrical Controls

Section 6│Frequently Asked Questions
Contents
• Airtightness
• Mould Growth
• U-Values
• Thermal Bridging
• Thermal Bridging + Structure

nZEB │ 06: Frequently Asked Questions
Scott Tallon Walker Architects
Airtightness
It is vital to reduce air infiltration in a
structure. The additional costs of air
tightness measures is negligible, but is
entirely reliant on build quality.
TGD Part L Non-Domestic 2017 requires a
minimum of airtightness of 3 ACH.
If a design tam wish to achieve a higher
rated building performance and the 10%
renewable target – A high airtightness
value will be required.
Note: The graph shows the annual heat gains
and losses of two version of a domestic
dwelling, with the only difference being
airtightness.
The first house has a 5 Air change per
hour and the second has the minimum
Passive House requirement of 0.6 ACH.
The result is an energy saving of 40%
thank to a reduce in heat losses.
32.6
7
5
4.9
14.2
14.2
4
3.2
8.2
8.1
7.4
7.4
11.4
7.7
34.6
13.7
22.4
18.3
25.8
20.4
0
10
20
30
40
50
60
70
80
90
5.0 ACH Losses 5.0 ACH Gains 0.6 ACH Losses 0.6ACH Gains
Comparing Airtightness
Ventilation Thermal Bridge Windows Floor
Roof External Walls Non-useful Heat Gains Heat Demand
Internal Heat Gains Solar Heat Gains
Section 5│ Airtightness

Mould Growth
The mould grows over a wide range of
temperatures, but favours
temperatures similar to those inside
building and wall build-ups.
Irish building regulation has a minimum
requirement for surface temperature (fRSI),
the requirement of which have to be
covered by the designer's professional
indemnity insurance.
The surface temperature factor is
established by dividing the measured
surface temperature by the difference in
temperature between the inside and
outside air (20˚C as per ISO standards).
See adjacent table for TGD Part L - Non-
Domestic (2017) fRSI requirements.
Section 5│Mould Growth

Minimal Domestic Part L Requirement Preferred Value
Walls - Insitu Concrete (Brick Finish)
Part L 2017: Table 1 - Maximum Elemental U-value
• Walls: 0.21 W/m²K
Part L 2018: Table 1 - Maximum Elemental U-value
Passive House recommendations
Section 5 │Improved U-Values
Minimal Non-Domestic Part L Requirement
Approx. 580mm Approx. 630mm Approx. 680mm

Thermal Bridges
Thermal bridging occurs in building
envelopes where there are gaps or breaks
in the insulation envelope creating
pathways for heat loss.
Thermal bridging also occurs in building
envelopes when materials with higher
thermal conductivity (such as steel, timber
and concrete) are used. These materials, if
not properly detailed, will create pathways
for heat to bypass the thermal insulation.
Types of Thermal Bridges:
• Linear Thermal Bridges
• Repeating Thermal Bridges
• Non-Repeating Thermal Bridges
• Geometrical Thermal Bridges
Heat always looks for the path
of least resistance
Section 5│Thermal Bridges

Minimising Thermal Bridging
The need for structural integrity, and the
need to allow light and access into a
building leads inevitably to the use of
different materials with different thermal
properties.
Good design of each of these details to
minimise the thermal loss is crucial both to
keep heating demand down and to avoid
cold spots where condensation might form.
Have as much of the structure
as possibly inside the thermal
envelope
No penetrations means no
Thermal Bridges
Retrofit Window Details
1. Solid Block Wal – No Insulation
2. External Insulation to Wall +
Large Thermal Bridge through
existing Concrete Sill
3. External Insulation to Wall, which
Window within the Insulation
Layer

Develop a Library of
Standardised Thermally Modelled
Details
TGD Part L – Non Domestic (2017) will
require all key junction detail to be
Thermally Modelled by an accredited
accessor
The NSAI, have established a national
register of Thermal Modellers (there are
currently on 14 in the country).
The typical cost to thermal model a detail:
• €200-300 for a 2D thermal model
• €300-400 for a 3D thermal model.
• With a 2-3 day turnaround time for each
detail.
It is prudent to develop an internal library of
accredited standard details to minimise
cost and time delays

The majority of worst offending thermal
bridges come from structural elements
entering and exiting the thermal envelope
The best approach is to design such
junctions out and ensure the entirety of the
buildings primary structure remains with
the insulated zone.
Where these junctions do occur, thermal
breaks must be introduced. Ancon, IKO,
Farat and Armatherm produce a number of
products. However the products can add
considerable cost to a projects budget
Section 5│Thermal Break: Structural

The multiple small bridges due to helping
hand brackets for façade systems and
cavity wall tie can amount to a significant
level of thermal bridging
Be aware of this when deciding on a
façade system. Once they are weighted
into a walls U-Value it may make it difficult
to achieve the Part L backstop U-Vales
Section 5│ Thermal Break: Helping Hand Brackets

Thermal breaks in steelwork are simpler
that concrete. A 15mm approx. section of
CompacFoam or similar is bolted in
between two junction places
However if there are multiple steel
elements penetrating the thermal envelope
this approach can become expensive
Recommendations
• Design out any unnecessary steel/
aluminium penetration of the thermal
envelope
• Structural connections for Balconies
are a particularly bad thermal bridge.
Section 5│ Thermal Break: Steel Junctions

This is a complicated junction due to the
structural load requirements and fire/
smoke risk if a fire starts in the lift pit.
Recommendations
• Insulated under the lift slab (120-
200mm of Polyisocyanurate (PIR)
insulation board)
• Shaft wall must be thermally isolated
• Either the base of the lift shaft is
wrapped in isolation at the base as
the shaft walls are warm (as per
image)
• Or the entire lift shaft is wrapped in
external insulation and the lift shaft
becomes thermally untreated space
(cold)
Section 5│ Thermal Break: Lift Shafts

Thank You
and Good Luck

Appendix Additional Advice
Contents
• NZEB Advice
• NZEB Examples

nZEB │ Appendix
It is always cheaper to do
the job right the first time
- Phil Crosby
Some basic thing to watch out
for on a nZEB project
Appendix│ NZEB Advice

nZEB │ Appendix
Orientation
Basics: Sun rises in the East and sets
in the West
Obvious as it may seem, it is important to
remember that during winter the sun
actually rises south of east and in the
summer rises north of east.
So in the summer north facing facades will
very briefly be exposes to the sun.
It is important to consider the suns path
when design areas which may develop
micro-climates: sunken or sheltered area,
sun rooms + gardens and atrium spaces.
It is also important to consider the potential
impacts of glare from the low winter sun
when developing BREEAM and LEED
projects.
Appendix│ Design Advice

nZEB │ Appendix
Form Optimisation
Basics: Compact building use less
energy
The greater the surface areas of a building
envelope, the more energy it will loss
through fabric loss, thermal bridges and air
permeability.
A sphere has the smallest surface area by
volume (form factor) of any form. In the
winter a single storey home could use up to
25% more energy compare to a two storey
home of the same floor area
The best form is a slight elongated solar-
orientated form that provides a balance
between solar heat gains and heat losses

nZEB │ Appendix
Rationalise the Layout
Basics: Cold Rooms to the North, Warm
Rooms to the South – use
buffer zones
It is wise to plan a building such that rooms
that require little to no heating or are only
occupied occasionally (toilets, store room,
bedrooms etc) are located on the northern
face with ‘active’ room to the southern face.
This rule is based on the ‘servant and
served’ principle of space planning.

nZEB │ Appendix
Fabric First
A phrase that will become more prevalent
thanks to nZEB. ‘Fabric First’ is the
principle that the majority of a building heat
is lost and gained through its fabric.
Insulation is a barrier to heat flow both
inward and outwards of a structure and is
required to maintain an appropriate level of
thermal comfort.
Basics: The basic rule is to wrap the
buildings external envelope
continuously (including under
the floor slab) with 200 -
300mm of insulation
Significant amount of energy is
also lost due to the infiltration
of external air, mostly through
poor quality construction
junctions which are not airtight.
Insulation is the cheapest and most
effective way to save energy.
Insulation first, then Renewables

nZEB │ Appendix
Overheating
With the increase in U-value requirements
and airtightness under TGD Part L - Non-
Domestic (2017), the potential for
overheating will increase.
There are a number of definitions for
overheating; CIBSE defines it as:
‘internal temperature of 28˚C is surpassed
for over 1% of the time’ and Passive House
as: ‘25˚C is surpassed for over 1% of the
time’. It is recognised that an internal
temperature of above 35˚C will create a
significant danger of heat stress.
The Irish TGD does not define overheating
but the designer should specify what the
indoor comfort they wish to achieve and
perform an overheating assessment.
However, any overheating risk can be
reduced or eliminated thought the
appropriate design decisions

nZEB │ Appendix
Thermal Comfort
Every person has a different opinion on
what is a comfortable internal temperature,
typical a temperature range of 18-22˚C
with a humidity of 40-60% is comfortable
for human being.
Building services typical aim to provide a
internal environment of:
• 20˚C @ 50% RH
Any internal temperature of over 25˚C is
consider to be overheating.
Note: TGD Part L does not have a
requirement to address
overheating in a building.
However, Passive House
requires the number of hours in
a year that exceeds 25°C to be
limited to 10% annually.
+ Keeping cool what should be kept cool
+ Keeping warm what should be kept warm
+ Without energy consumption
= Comfortable Environment

nZEB │ Appendix
Limiting Heat Gains
Guidance is provided in DEAP for carrying out overheating assessment.
Reasonable provision to limit heat gains can be demonstrated by showing through the DEAP calculation that the dwelling does
not have a risk of high internal temperatures. (revised DEAP methodology to be published).
Where an overheating risk is indicated in DEAP, further guidance is provided in CIBSE TM 59 to ensure overheating is avoided
for normally occupied naturally ventilated
spaces.
CIBSE TM 37 provides the following
recommendations and further guidance to reduce or avoid solar overheating:
a) Layout: planning the layout and orientation of buildings and rooms to maximise the benefits of sunlight and minimise the
disadvantages.
b) Solar shading: this may include external, internal or mid-pane shading devices, or solar control glazing.
c) Thermal mass: an exposed heavyweight structure, with a long response time, will tend to absorb heat, resulting in lower
peak temperatures on hot days. Night-time venting and acoustic requirements should also be considered.
d) Good ventilation: a reasonable level of ventilation will always be required in buildings to maintain indoor air quality. The
ability to switch to a much higher air change rate can be a very effective way to control solar overheating, e.g. cross
ventilation, stack ventilation or mechanical ventilation.
e) Reducing internal gains: by the use of e.g. energy efficient equipment, lamps, luminaires and controls.

nZEB │ Appendix
Solar Shading
As designers there are a range of solutions
for solar shading and prevent unwanted
solar gains
External shading devices preform better
than internal methods as they completely
prevent the sun’s rays from entering the
building. Internal blinds, while prevent solar
glare, will not prevent overheating
Basics: Southern solar shading should
be horizontal due to high angle
of the summer sun.
East or West shading should
be vertical to shade against the
low angle of sun.
Sothern Shading East/ West Shading

nZEB │ Appendix
Thermal Mass
High thermal mass building elements will
absorb heat slowly and store it. The store
heat will then be released slowly into the
building
In buildings with high thermal mass, the
highest indoor temperatures will occur in
the early hours of the morning, typically a
number of hours after the highest outdoor
temperatures have been reached.. This
slow response time is know as the
‘Thermal Flywheel Effect’
Note: In highly insulated building with
a stable internal temperature
the benefits of thermal mass
can be limited. Without internal
temperature flocculation the
stabilising effect of thermal
mass is irrelevant.

nZEB │ Appendix
Lightweight Structures
Lightweight structures with a low thermal
mass are better suited to building with a
intermittent use, which need to be heated
quickly or are less sensitive to thermal
comfort requirements.
These buildings need to be well insulated
and benefit for a quick response heating
systems.
Heavyweight Structures
Heavyweight structure favour building
which are in constant use as internal
temperature swings are naturally
dampened and the heat gains are retained.
It is important to plan for the time lag
between the maximum internal and
external temperatures to prevent potential
overheating in the summer or valuable heat
energy being flushed away by the
ventilation system or night cooling

nZEB │ Appendix
Real Collaboration
Due to the added complexity of achieving
the nZEB energy standard, a collaboration
between the construction team is essential.
Full buy-in from the design team is
required. Primary and secondary structures
are the principal causes of thermal bridging
and the oversizing of mechanical service is
a major source of additional cost.
Most important the main and sub-
contractors need to be fully aware of the
requirements and the additional pressure
they put on on-site quality control.
nZEB cannot be delivered with a
‘business as usual’ attitude
Appendix│ Construction Advice

nZEB │ Appendix
Tender + Fear Factor
A substantial upskilling of onsite contractor
is required in order to meet the nZEB
standards. While there are a number of
programmes nationally aim at this, they
have not seen widespread adoption by the
construction industry.
The need to educate key onsite member
will inevitably effect tender prices and
construction programmes. There is also the
prospect of contractors applying a ‘fear
factor’ sum - overpricing works which they
are unsure or unfamiliar with.
When drawing up tender documentation,
clarity must be provided on
• The high level of construction quality
• The additional level of inspections
(recommended multiply airtightness
test to ensure a consistent
performance)
• Any additional foreman responsibilities
• All damages or bonuses associated
with meeting key requirements

nZEB │ Appendix
Buying Design Risks
The majority of cost-saving measures
regarding the implementation of nZEB are
made at both the initial design and design
development stages of the project
programme.
Combined with the TGD Part L - Non-
Domestic (2017) implementation date of
early 2019, presents a potential risk when
bidding for projects at Construction stage
only.
There will be significant manhours and cost
in upgrading a substantively completed
design to the new TGD Part L - Non-
Domestic (2017) standards.

nZEB │ Appendix
Fixed Design at Construction
The TGD Part L – Non-Domestic (2017)
requirements for thermal modelling of all
details in addition to the complications of
NEAP software and the Renewables
requirements. This will result in any change
to the building strategy during construction
being onerous and potentially costly.
For example, if a Contractor changes the
specified wall insulation material with a
similar product with a different U-value and
thermal bridging properties (y-factor). Then
a new thermal model will have to be
produced and the building energy
requirements reassessed.
There is considerable risk related to
undeveloped details or service strategies
being issued for tender.
If you haven’t drawn it - You
haven’t thought about it

nZEB │ Appendix
Appendix| Typology
Key Question
What will an
nZEB look like?
Vandermaelen
Development,
Brussels
nZEB │ Appendix

nZEB │ Appendix
nZEB | Domestic Example
Silken Park
Location: Citywest, Co. Dublin
Completion: April 2018
BER: A2 (47-49.6 kWh/m²/yr)
Passive House Certified
Developer: Durkan Residential
Architect: BBA Architecture
Building type:
•Phase 3 of a private development,
consisting of a mix of terrace, semi-
detached and detached houses.
•Twenty-four 2-bed terraced/ semi-
detached houses (84m²),
• Twenty-nine 3-bed terraced/semi-
detached houses (109m²),
• Five 4-bed semi-detached houses
(120m²)
• One 4-bed detached (126m²)
• All 59 houses will come pre-wired for EV
charge points
• Roofs are designed to take the weight of
a solar PV system covering the whole roof

nZEB │ Appendix
Scott Tallon Walker Architects
nZEB | Apartment Example
Roebuck Student Residences
Location: UCD
Size: 3097m2
Completion: 2010
BER: A3
Heat Demand: 12kWh/m²/yr
Primary Energy: 114kWh/m²/yr
PH Certified
Architect: Kavanagh Tuite Architects
Building Info:
• 6 storeys high, housing 300 students
• Residence style accommodation with en-
suite student rooms, kitchenette and
living on either side of a spine corridor
• External walls formed in structural
concrete, cast with permanent magnetizes
formwork requiring decoration finish only
Roof: 0.150 W/(m2K)
Walls: 0.170 W/(m²K)
Floor: 0.150 W/(m2K)
Glazing: 0.800 W/(m2K)
Curtain Wall: 1.200 W/(m2K)
Air Permeability: 0.600 ACH
nZEB │ Appendix

nZEB │ Appendix
nZEB | Office Example
Enexis Regional Office
Location: Maastricht, Netherlands
Size: 5912 m2
Completion: 2013
Cost: €6,715,500
Primary Energy: 34.7kWh/m²/y
Architect: Kent Pedersen Architects
Building Info:
• BREEAM excellent
• First Energy-Neutral design certificate in
the Netherlands
• The building has energy-efficient
lighting, daylight control, presence
detection
• PV cells on the roof
Climate Control: Demand Controlled
Solar Water Heater: 13.3m²
PV: 1406m²
Cooling: Free Cooling
Ventilation: Balanced
nZEB │ Appendix

nZEB │ Appendix
nZEB | Office Example
GouweZone
Location: Gouda, South Holland
Size: 2747 m2
Completion: 2012
% of Renewables: 74%
Architect: EGM Architects
Building Info:
• A energy-neutral office development
• Completely CO2 neutral and uses 70%
less energy than typical office buildings
• All electric
• Tenants offered a multi-year contract
with a fixed all-in price in terms of
energy costs.
Heating: Electric Heat Pump
Delivery: Underfloor Heating and
Concrete Core Activation
PV: 620m²
Cooling: Free
Ventilation: Balanced
nZEB │ Appendix

nZEB │ Appendix
nZEB | Education Example
CREST
Centre for Renewable Energy & Sustainable
Technologies
Location: Enniskillen
Size: 455 m2
Completion: 2014
PH Certified
Architect: Paul McAlister, The Barn Studio
Building Info:
•Large areas of glazing to the south assist
with solar gain and allows natural light to
penetrate deep into the floor plan
• Reduces the amount of artificial light
required to the exhibition spaces.
• Utilises air to water heat pump, with
underfloor distribution
Roof: 0.160 W/(m2K)

nZEB │ Appendix
Plein Oost School
Location: Haarlem, Noord-Holland
Size: 2521 m2
Completion: 2014
% of Renewables: 92%
Architect: Kristinsson
Building info:
• The school is energy-neutral
• Building houses two schools with
outdoor space and gym, a playgroup and
an after-school care centre
• Solar panels are installed with an east-
west orientation at an angle of 10
degrees
• The school board signed an agreement
with the municipality to finance the extra
investment , this is earned back through
lower energy and maintenance costs
PV: 672m²
Cooling: Heat Pump 27 MJ /m²
Ventilation:Balanced
nZEB │ Appendix

nZEB │ Appendix
Centre for Medicine
Location: University of Leicester
Size: 9863 m2
Completion: 2014
Cost: £42,000,000
PH Certified
Architect: Associated Architects
Building Info:
• BREEAM Excellent
• Reduced annual energy bills by 80%.
• Heating from local district heating
• Minor cooling from pipes in slabs
• Hot water from local electric heaters,
successfully avoided distribution losses
• Largest green wall in the UK outside of
London
Roof: 0.122 W/(m2K)

nZEB │ Appendix
nZEB | Sport Hall Example
Södra Climate Arena
Location: Växjö, Sweden
Size: 3589 m2
Completion: 2012
PH Certified
Architect: Kent Pedersen Architects
Building Info:
• Tennis hall with four tennis courts, a
cafe, conference rooms, a gym,
changing rooms and technical facilities
• The hall is heated by air, the rest of the
rooms have radiators
• The entire system is demand-controlled
Roof: 0.068 W/(m2K)

nZEB │ Appendix
nZEB | Retail Example
Tesco
Location: Tramore, Waterford
Size: 3970 m2
Completion: 2008
Primary Energy: 758 kWh/m²/yr
PH Certified
Architect: Joseph Doyle Architects
Building Info:
•First certified Passive House supermarket
in the world
•Waste heat of refrigeration plant
connected with ventilation system
• Uses 45% less energy than a
supermarket of a similar size saving 420
tonnes of carbon dioxide per annum
Roof: 0.15 W/(m2K)
Floor: 3.68 W/(m2K)
Perimeter insulation only - Ground below
building acts as a heat storage

nZEB │ Appendix
nZEB | Retail Example
Quirke’s Pharmacy
Location: Clonmel, Tipperary
Size: 229m2
Completion: 2014
BER: A2 (46.75 kWh/m²/yr)
Heat Demand: 12 kWh/m²/yr
Primary Energy: 150 kWh/m²/yr
PH Certified
Architect: PassivHaus Architecture
Building info:
•Combined pharmacy at the ground level
and an apartment above
•Third non-residential passive house
building in Ireland
•Original building was over 200 years old,
and in poor condition before renovation
•Came in on budget, and opened a month
ahead of schedule
Roof: 0.097 W/(m2K)
nZEB │ Appendix

nZEB │ Appendix
Appendix | Databases
Passive House Project Database
http://www.passivhausprojekte.de
Netherlands Enterprise Agency
Energy Efficient Construction Database
https://www.rvo.nl/initiatieven/overzicht/27008

STW Sustainable/ NZEB Design Presentation - Nov 2019

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