Creating Low Energy Buildings, Energy at Home Event on Sustainable Buildings, Folly Farm Centre, 18th March 2015

creating low energy buildings
Colin Powell BA(Hons) DipArch Msc RIBA
gcp : architecture : energy : sustainable design

Content
• Energy – understanding the numbers
• Low energy design – step by step
• Going further – PassivHaus introduction
• Challenges for the designer
• Challenges for the builder
• Q & A

gcp
architecture : energy : sustainable design
Effective sustainable design
requires a detailed knowledge
of building science, technology
and construction
Our core skills as architects
provides our clients with a
depth of understanding that
informs our advice on energy
and sustainability
Our consulting business
provides the specialised
knowledge of sustainable and
low energy design needed to
help our clients achieve their
ambitions
i n t r o d u c t i o n

gcp
Being comfortable in our
home uses energy, for
heating, lighting, hot water
and appliances
To design low energy
homes the first thing we
need to understand is
where the energy all goes
to
Its all a matter of balance!
u n d e r s t a n d i n g e n e r g y i n b u i l d i n g s

gcp
The energy we use is
affected by different
factors
• Age of the building
E n e r g y i n b u i l d i n g s
62%
19%
13%
3%
3%
Home Energy
Heating
Hot Water
Appliances
Lighting
Cooking
Energy use – average all UK homes

gcp
The energy we use is
affected by different
factors
• Age of the building
• Lifestyle
• Purchasing decisions
E n e r g y i n b u i l d i n g s
32%
22%
29%
9% 8%
Home Energy
Heating
Hot Water
Appliances
Lighting
Cooking
Energy use – new home to current regulations

gcp
Heat loss from the
building has to be
balanced with energy
(heat) in to maintain
comfort
We can calculate where
this heat is lost by
modelling
S o w h e r e d o e s a l l t h e e n e r g y g o ?

gcp
Heat loss from the
building has to be
balanced with energy
(heat) in to maintain
comfort
We can calculate where
this heat is lost by
modelling
S o w h e r e d o e s a l l t h e e n e r g y g o ?
walls
13.2
roof
9.2
floor
4.0
windows
24.2
ventilation
48.0
Current Regs - elemental energy loss – kWh / m2
Therm.
bridges
2.7

gcp
s t e p s t o l o w e n e r g y d e s i g n
HANDOVER
ORIENTATION - SHADING - SHELTER - SUN
FORM - INTERNAL LAYOUT - SERVICES
INSULATION - AIRTIGHTNESS - THERMAL BRIDGES
THERMAL MASS
APPROPRIATE - EFFICIENT - SIMPLE
CONTROLLABLE
PERFORMANCE - INSTALLATION
OPERATION - UNDERSTANDING - CONTROL
COMMISIONING
RENEWABLES
SERVICES &
CONTROLS
BUILDING FABRIC
LAYOUT DESIGN
SITE

gcp
s t e p s t o l o w e n e r g y d e s i g n
SITE
LAYOUT DESIGN
BUILDING FABRIC
SERVICES &
CONTROLS
RENEWABLES
COMMISIONING
HANDOVER
ORIENTATION - SHADING - SHELTER - SUN
FORM - INTERNAL LAYOUT - SERVICES
INSULATION - AIRTIGHTNESS - THERMAL BRIDGES
THERMAL MASS
CONTROLLABLE
PERFORMANCE - INSTALLATION
OPERATION - UNDERSTANDING - CONTROL

gcp
H a c k n e s s F a r m – E a s t H u n t s p i l l
access access
mid-day
sun
• south-facing for passive solar gain
• Internal house layouts adapt to changing
entrance positions

gcp
• Internal layout: all main
rooms oriented to
south
• Ability to enter house
from north or south
• Larger windows to
south
• Smaller windows to
north
• Large south facing roof
for solar
• Simple (electric)
heating through fabric
efficiency

gcp
Traditional
construction
• Understood by
contractor, but tends
to greater complexity
• Challenges for
achieving airtightness
• Additional supervision
to maintain high
quality
• Importance of
controlling changes

gcp

gcp
Govt. Agenda for Carbon
Reduction – Climate
Change Act
35% Reduction in CO2 by
2020
Increasing energy costs
and prospect of increasing
energy instability
D o w e s t i l l n e e d t o w o r r y ?
DECC – monthly retail price indices
0
20
40
60
80
100
120
140
160
180
200
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
Fuel price indices in the domestic sector in real
terms 1992 to 2012
Coal and
smokeless fuels
Electricity
Gas

gcp
PassivHaus is a design
standard for producing
buildings with very low
energy demand
Developed in Germany in
1991, now being used
around the world as a tried
and tested standard
Market for PassivHaus in
Europe is huge. Market in
the UK is developing with
growing speed
C a n w e d o b e t t e r ?

gcp
Standard applicable to all building typesPassivHaus focusses on
building energy calculated
through a rigorous
calculation method
Not only applicable to
housing, it can be used for
large and small buildings
EnerPHit standard applies
PassivHaus principles to
refurbishment and retrofit
offices
schools
housing
student residence
q u i c k o u t l i n e

gcp
0
50
100
150
200
250
UK average
Part L 2010
PassivHaus
• Low carbon buildings are
not necessarily low energy
buildings!
• Focus on creating
buildings with energy use
significantly lower than
current normal practice
• Low Energy buildings =
Low Carbon buildings
- without the plug-in
technology fixes!
W h y P a s s i v H a u s ?
Specific heating demand – kWh / m2

gcp
Exeter City Council
Hastoe Housing Group
Interserve
University of East Anglia
Leicester City Council
Circle Housing
Gentoo
Diocese of Worcester
University of Bradford
London Borough of Tower Hamlets
Carmarthenshire Council
East Midlands Housing Association
Raynsway Properties
Estimated over 500 completed projects
by end 2013 a rate of growth
consistent with Germany 20 years ago
(NHBC Foundation July 2012)
W h y P a s s i v H a u s ?
“healthy
buildings”
“addresses
fuel poverty”
“reduced
management &
maintenance”
“future
proof”
“not eco-
bling”
“demonstrates
CSR”
“fabric first”
“massive cost
saving”
“tried &
tested”
“opportunity
for higher
revenue”
“right thing
to do”

gcp
• Exceptionally high thermal
insulation
• High performance triple
glazed windows
• Thermal-bridge-free
construction
• Very low air permeability –
airtight building envelope
• Comfort ventilation with
highly efficient heat
recovery
continuous thermal insulation
typically >300mm thick
larger windows to the south for
beneficial solar gains
continuous air barrier
To prevent air leakage
ventilation system delivers
fresh air to main activity
spaces
ventilation with
Heat recover to
save energy
F i v e p r i n c i p l e s

gcp
R e m i n d e r – w h e r e w e a r e n o w.
walls
13.2
roof
9.2
floor
4.0
windows
24.2
ventilation
48.0
Current Regs - elemental energy loss – kWh / m2
Therm.
bridges
2.7

gcp
• There are over 37,000
completed PassivHaus
projects in Europe and
around the world
• There are approximately
46 completed PassivHaus
schemes in the UK
I t i s p o s s i b l e t o g o m u c h f u r t h e r !
walls
8.4
roof
5.2
floor
3.3
windows
13.7
ventilation
5.6
Therm.
bridges
0.0
PassivHaus - elemental energy loss – kWh / m2

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• Increased cost for
construction is invested
in the building fabric and
insulation
• Typically 5-10% more
expensive
(recent studies show
this reducing)
• Payback period around
20 years
(but energy costs
increasing)
• Protection against
fluctuating fuel costs and
future uncertainty
C o s t s a n d b e n e f i t s
Illustration of energy cost savings for a 3-bed detached house

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• Stable internal
temperatures without cold
surfaces or draughts
• Reduced risk of overheating
• Controlled ventilation can
reduce the risks of
respiratory disease
• Thermal performance and
air-tightness through
rigorous quality control at
design and construction
stage
Image courtesy of International PassivHaus Association
I t s n o t j u s t a b o u t m o n e y “We think each person lifted out of fuel
poverty will save the health service about
£250 a year. Data suggests there are 20%
more deaths in Oldham in winter than in
summer because of extra respiratory
illnesses and heart problems [linked to cold
homes]. If you get a cold winter and people
cannot heat their homes, you get more
people suffering and turning up in A&E”
(Guardian Nov.13 – ‘Actively cutting energy bills
in Oldham – Welcome to the Passivhauses’)

gcp
• What is important?
• Building form is a
crucial factor that
should be understood
as early as possible in
the design process
• Easier to achieve PH
standards with larger
buildings with more
efficient form factor
• Simpler building form is more efficient
• Relationship between building volume to surface
area will affect fabric insulation - and cost
t h e d e s i g n c h a l l e n g e

gcp
Goose Chase
• 200 sqm PassivHaus
• Site not ideal
• Overheating risk to
design out
• Simple form and
construction for ease of
build

gcp
Goose Chase
• ICF construction
• Fast and easy to build
• Highly insulated
• First air test 0.45 AC/H

gcp
• Simpler PassivHaus
buildings are more efficient
and easier to realise
• For designers early
understanding of the
necessary parameters is
vital
• Easier to build
• Easier to manage quality
• Easier to certify
• Reducing costs through
optimised solutions
Develop construction strategy at design stage

gcp
• Airtight construction
• Interior space enclosed in
a continuous barrier to
reduce uncontrolled
ventilation
• Materials and methods of
construction and jointing
• Position and protection
• Junctions and sealing
• Site control to achieve
continuity and avoid
damage
• Planning service installation to protect air barriers
t h e c o n s t r u c t i o n c h a l l e n g e

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• Thermal bypass can reduce the effectiveness of
insulation by as much as 70%
Thermal bridge-free
• Thermal bridges are
created by fixings or
structural connections that
pass through insulation
• Thermal bridges can also
be formed by ‘thermal
bypass’ i.e. gaps in or
around the insulation
• PassivHaus aim is to have
zero thermal bridging
• Site control to ensure
careful installation and
sealing of insulation

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Materials innovation
• Increased technical
requirements of
construction
• Prefabrication enables
quality control and ease
of construction
• Speedier construction
• Recycled content

gcp
• PassivHaus is a proven
standard based on
rigorous building physics
• Needs to be a target from
the outset
• All design decisions made
in the context of energy
implications
• For clients with on-going
responsibility for building
running costs PassivHaus
can offer ‘fixed’ energy
costs and early return on
investment
s u m m a r y
Fox Barn Hampshire – Jackson Planning
Student housing Dublin – Kavanagh Tuite Architects
Wimbish – Parsons + Whitley Architects

thank you
www.gcparch.co.uk
colin.powell@gcparch.co.uk
gcp: delivering effective low-energy buildings
• Collaborative
• Supportive
• Creative
• Pragmatic
• Professional

Creating Low Energy Buildings, Energy at Home Event on Sustainable Buildings, Folly Farm Centre, 18th March 2015

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Creating Low Energy Buildings, Energy at Home Event on Sustainable Buildings, Folly Farm Centre, 18th March 2015