This document discusses the requirements for Near Zero Energy Commercial Buildings (NZEB). It outlines that NZEB buildings must have a high performance thermal envelope to limit heat loss and solar heat gains, requiring stringent insulation standards. Buildings must also utilize high energy efficient systems for heating, ventilation, air conditioning, lighting and renewables to meet energy targets. The standards apply to new buildings and major renovations starting in 2019, with some transitional arrangements allowing use of older standards if planning or substantial construction was completed by set deadlines.

1. NZEB – Near Zero Energy Commercial Buildings
Henry J Lyons

2. NZEB in a NUTSHELL
+ + =

3. High Performance Thermal Envelope
Limit the heat loss through the fabric of the
building
Limit Solar Heat Gains – Reduce need for
mechanical cooling. Where such systems are
required, ensure they are energy efficient.

4. FABRIC FIRST – Thermal Performance of Building Elements
Limit the heat loss through the fabric of the building
Back Stop U-Values (Part L – 2008 Figures in Red)
0.27 W/m²K
0.25 W/m²K
0.25 W/m²K
0.27 W/m²K
Unheated Space
0.22 W/m²K
0.16 W/m²K
0.27 W/m²K
0.20 W/m²K
0.25 W/m²K
2.2 W/m²K

5. FABRIC FIRST – Thermal Bridging Calculations
Limit the heat loss through the fabric of the building
Back Stop U-Values (Part L – 2008 Figures in Red)
0.12 W/mK
0.16 W/mK
0.09 W/mK
0.07 W/mK
0.30 W/mK
0.04 W/mK
0.05 W/mK
0.12 W/mK
0.16 W/mK
0.09 W/mK
0.07 W/mK
0.30 W/mK
0.04 W/mK
0.05 W/mK

6. FABRIC FIRST – Reduce Solar Heat Gain
Limit Solar Heat Gains – Reduce need for mechanical
cooling. Where such systems are required, ensure they
are energy efficient.

7. FABRIC FIRST – Reduce Solar Heat Gain

9. FABRIC FIRST – Air Permeability
Limit the heat loss through the fabric of the building
Back Stop Value of 5m³/hr/m² (Part L 2008 - 10m³/hr/m²)

10. High Energy Efficient Systems
Heating Plant:
• Heating Plant Efficiency
• Controls for Space Heating and Hot
Water
Mechanical Ventilation and Air-
Conditioning
• Specific Fan Power
• Cooling Plant Efficiency
• Controls – Reference case has Demand
Controlled Ventilation
Artificial Lighting
• Luminaire Efficacy – Lumens per Circuit
Watt
• Controls – Manual Switching /
Daylighting /
Presence Detection

11. On Site Renewables
Renewable Energy Ratio:
There are 2 routes to achieve compliance
with the renewable energy target:
Route 1 – if the BER target of A3 is achieved
with no tolerance (0% margin), 20% of the
building energy must be provided by
onsite/near site renewable technologies
Route 2 – if the BER target of A3 is achieved
with a minimum of 10% margin, then 10% of
the building energy used must be provided by
onsite / near site renewable technologies
• Solar PV
• Combined Heat & Power (CHP)
• Heat Pumps
• District Heating
• On Site Wind Generation

12. Transitional Arrangements
In general, these requirements applies to
works, or buildings in which a material
alteration or change of use or major renovation
takes place, where the work, material
alteration or the change of use commences or
takes place, as the case may be, on or after 1st
January 2019.
However, the 2008 standard may continue to
be used in the case of buildings:
• Where the work, material alteration or the
change of use commences or takes place, as
the case may be, on or before 31st
December 2018,
or
• Where planning approval or permission for
buildings has been applied for on or before
31st December 2018, and substantial work
has been completed by 1st January 2020.
“Substantial work has been completed” means
that the structure of the external walls has
been erected.
CSO Figures

20. pat.kirwan@hjlyons.com
@patkirwan