The Interim NZEB Specification for Public Sector buildings sets out a performance specification for new buildings owned and occupied by Public Authorities after 31st Dec 2018. It is intended that this specification will form the Nearly Zero Energy Buildings requirement in the interim period until the new 2017 Part L for Buildings other than Dwellings takes effect.

1. Nearly Zero Energy Buildings
(NZEB) for Public Sector
Seán Armstrong,
Housing/Building Standards Section,
DHPCLG

2. Todays Objectives
• Explain the Public Sector Interim Nearly
Zero Energy Building Specification
• To learn how to apply it using
NEAP/SBEM
• To gather feedback on Interim NZEB
Public performance requirements

3. Outline
• Implementing the Energy Performance of
Buildings Directive
• What are Nearly Zero Energy Buildings
• How does it apply to Public Sector
• Next Steps

4. Article 9 Requirements include:
• All new buildings to be “Nearly Zero Energy Buildings” by 31st Dec 2020
• New buildings owned and occupied by Public Authorities to be `Nearly
Zero Energy Buildings’ after 31st Dec 2018
• Major Renovations in Building Codes to be at Cost Optimal Level.
Recommendations on NZEB issued by Commission in July 2016
• Member states should take account of “the period of validity of building
permits, the length of construction and completion of building works” to
avoid falling short of the NZEB target dates in the EPBD.
Energy Performance of Buildings Directive (EPBD)

5. Implementation of EPBD
• TGD L Buildings other than Dwellings is currently under review to provide
detailed NZEB guidance and include Major Renovations performance
requirement:
– Public Consultation – 24th February 2017
– Final Publication-Mid 2017
– Application- planned for early 20191
• NZEB Interim Specification for Public Buildings issued 23rd Dec 2016 for
buildings commencing design in early 2017
• SI 4 of 2017 has amended Building Regulations to include the definition
of NZEB
• TGD L Dwellings 2011 has been amended to include NZEB Definition of
an MPEPC of 0.30 and MPCPC of 0.35 for dwellings completed after 31st
Dec 2020
1 Subject to Regulatory Process

6. EPBD Definition- Nearly Zero
Energy Building
‘nearly zero-energy building’ means a building that has a very high energy
performance, as determined in accordance with Annex I. 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;
RTE PV Array

7. Commission Recommendation
for offices-July 2016
• Offices
85-100 kWh/(m2.y) of primary energy use
covered by 45 kWh/(m2.y) met by on-site
renewable sources

8. Public Sector Interim NZEB Specification
• Issued by DHPCLG on 23rd December 2016 to all
Government Departments, Agencies and Local Authorities
• Developed in conjunction with OPW, DES, HSE and SEAI
• Available to download from SEAI website
• Intended to be used until by Public Sector new Part L-
Buildings other than Dwellings applies in early 2019
• Should be used for all buildings owned and occupied by
Public Authorities expected to be completed after 31st Dec
2018
• Detailed guidance on application and Renewables Calculation
tool to be issued in the coming week

9. Key Components of
performance requirement
• Provides an improvement in performance in the
order of 50% to 60% over 2008 TGD L
• Improved Fabric Specification
• Advanced Services and Lighting specification
• Renewable Energy Ratio of 20%
.

10. Performance requirements for Public Sector
Specification Reference Building-Fabric
Parameter Current reference values-TGD
L 2008
Reference values-Public
Sector Specification
Total Floor Area and
Building Volume
Same as actual building Same as actual building
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
Walls U=0.27 W/m2K U=0.18 W/m2K
Roofs U=0.16 W/m2K U=0.15 W/m2K
Floor U=0.25 W/m2K U=0.15 W/m2K
Thermal bridging Add 16% to fabric heat loss Actual Length of Key Junctions x
Advanced psi value
Air Permeability 10m3/(hr.m2) 5m3/(hr.m2) Floor area <250m2
3m3/(hr.m2) Floor area >250m2
Window U Value
Solar energy
transmittance
2.2 W/(m2K)
0.72
1.4 W/(m2K)
0.40

11. Services
Parameter Current reference values-
TGD L 2008
Proposed reference
values-TGD L 2017/Public
Sector Specification
Heating efficiency (heating
and hot water)%
0.73 CoP 91% Gas Boiler
Cooling Seasonal Energy
Efficiency Air conditioned
building
Ratio (SEER)
SEER=1.67 SEER=4.5
Lighting divide the illuminance
by 100, then multiply by 3.75
W/m2 per 100 lux
65 lm/circuit watt
Occupancy Control Local Manual Switching Automated
Daylight Control Local Manual Switching Automated
Central Ventilation SFP 2 (W/(l/s)) 1.8 (W/(l/s))
Variable speed control of
fans
No Yes
Renewable Energy Ratio None 20% using photovoltaics

12. Interim Public Sector Specification-Fabric Backstops
• New Backstops (W/m2K) as for TGD L-Dwellings:
– Pitched Roof 0.16
– Flat roof 0.2
– Walls 0.21
– Floors 0.21
– Windows 1.6
– Curtain walling 0.21
– Vehicle access doors 1.5
• Airtightness Backstop-5m3/(hr.m2)

13. Checking NZEB using NEAP
• Current version of SBEM 3.5 to be used - available on SEAI website
• Calculate the performance of the proposed building in SBEM using
the draft Interim Public Sector Specification for fabric and services.
This must be done manually using “table 1” from the draft interim
specification with same size and shape as actual building. This then
becomes the reference building.
• Calculate the performance of the proposed building in SBEM using
the actual design specification for the building
• Compare the primary energy (kWh/m2/yr) and carbon dioxide
emissions (kgCO2/m2/yr) between the building with the actual
performance specification and the building modelled with the draft
Interim Public Sector performance specification.

14. Checking NZEB using NEAP
• Where the actual building performance specification has a primary energy
performance equal to, or lower than the primary energy performance
(kWh/m2/yr) of the same building modelled using the draft Interim Public
Sector Specification it achieves the NZEB performance specification for
energy i.e. The Energy Performance Coefficient (EPC) must be equal to or
less than MPEPC =1.0
• Where the actual building performance has a carbon dioxide emissions
performance equal to, or lower than 1.15 times the carbon dioxide
performance (kgCO2/m2/yr) of the building modelled using the draft Interim
Public Sector Specification it achieves the NZEB performance specification
for carbon dioxide emissions. Ie. The Carbon Performance Coeffient (CPC)
Must be equal to or less than MPCPC =1.15
• EPC/CPC Spreadsheet calculation tool to be released on SEAI website in
coming week

15. • Renewables requirement will be included in TGD L Buildings other than
Dwellings as Renewable Energy Ratio (RER)-20%
• It is recognised that in certain confined situations it may not be possible to
achieve the full 20% RER. In these situations Public Sector Authorities
should provide the optimum proportion of energy from renewable energy
sources that is practically possible.
• In all cases the overall energy performance of the building should be
equivalent to the performance of the building as if the 20% RER had been
achieved.
• Renewable energy sources include Photovoltaics, Heat Pumps (Air source
and ground source), Biomass, Solar Thermal ,Primary Energy Savings
from Combined Heat and Power (CHP), Renewable district heating
• Primary Energy Factor for electricity for calculating RER–the same as
residential 2.19 (3 year forward look)
Interim Public Sector Specification RER

16. Costs
• Performance requirements are based on cost optimal
reports published in accordance with EPBD:
http://www.housing.gov.ie/housing/building-
standards/energy-performance-buildings/energy-
performance-buildings
• Table 5.3a of Non Residential Cost Optimal Report
provides Initial Investment Costs for the energy related
costs for different performance levels for 5 buildings.
• Further analysis currently being performed for RIA.
• Consultant appointed for TGD L 2017 and costs will
be available for TGD L Public Consultation-end Feb.

18. Table 5.3a contd.

19. TGD L-Draft Major Renovation
proposal
• Define as “more than 25% of the surface
area of the building envelope undergoes
renovation”
• Provide menu of measures to bring to cost
optimal:
– Upgrade inefficient heating systems
– Upgrade inefficient cooling systems
– Upgrade inefficient lighting systems

20. New Build:
- Walls 0.13 W/m2K
- Windows 0.82W/m2K
- Roof 0.11W/m2K
- Renewables-Pellet boiler
and 938m2 PV
EU Study CT5 Report Selected Examples of NZEB
http://www.epbd-ca.eu/wp-content/uploads/2011/05/CT5_Report_Selected_examples_of_NZEBs-final.pdf

21. Retrofit:
-Walls 0.13 W/m2K
-Windows 0.80W/m2K
-Roof 0.08W/m2K
-Renewables:Photovoltaic
and geothermal heat
pump

22. New Build
-Walls 0.14 W/m2K
-Windows 0.78W/m2K
-Roof 0.10W/m2K
-Renewables:Air source
heat pump

23. Efficiency House Plus with E-mobility in Berlin
Project aim:
This pilot building generates its own energy and makes it available to the users and the electric
vehicles. Excess energy is fed back into the grid or stored in a battery. An annual positive
energy balance is required for primary and final energy use.
Building address: Fasanenstraße 87a, 10623 Berlin
Building type: Residential Non-residential Public New Renovated
X X
Single-family house with 2 floors
Building size: 203 m² useful floor area (AN, with AN=0.32*Vgross), 138 m² living area
Building envelope
construction:
The floor, the walls and the roof are made of timber panels filled with up to 52 cm cellulose insulation. The windows have triple glazing. Thermal bridges
have been minimised. Photovoltaic modules cover the roof and the façade. All house elements can be separated and moved to another location or be
disposed of after the lifetime of the building.
Building envelope
U-values:
Wall 0.11 W/m²K
Window 0.70 W/m²K
Roof/ceiling to the attic 0.11 W/m²K
Cellar ceiling/ground slab 0.11 W/m²K
Building service
systems:
The house is heated by a central heating system with an air-to-water heat pump and floor heating. A
balanced mechanical ventilation system with 80 % heat recovery and a building energy management system
with touch pads are installed. The PV systems on the roof and facades generate electricity that is used by the
building, fed into the grid or stored in a battery. The battery, with a capacity of 40 kWh, is made of 7,250
single second-hand battery cells formerly used in electric cars.

24. Next Steps
• Public Sector Specification
– Public Sector Interim Specification available on SEAI Website
– Detailed guidance and RER calculation tool to be provided in coming
week
– DHPCLG ,OPW,DES ,SEAI and HSE working group to continue to
support specification
• TGD L 2017-Buildings other than dwellings
– Public Consultation of TGD L and Regulatory Impact Assessment by
24th Feb. 2017
– NEAP for TGD L 2017 to go for public consultation simultaneously
– Close of TGD L 2017 Public Consultation Mid-April
– Publication of TGD L by mid 2017
– TGD L 2017 planned to apply by start of 2019 (subject to regulatory
process)

25. http://www.seai.ie/Your_Building/BER/Non_Domestic_buildings/NZEB-
Commercial-and-Public-Sector/Nearly-Zero-Energy-Buildings.html
It is recognised that in certain
confined situations it may not be
possible to achieve the full 20% RER.
In these situations Public Sector
Authorities should provide the
optimum proportion of energy from
renewable energy sources that is
practically possible.
In all cases the overall energy
performance of the building should be
equivalent to the performance of the
building as if the 20% RER had been
achieved.

26. www.housing.gov.ie