2. Building Energy Rating
Construction Studies
An introduction to
Building Energy Rating

3. Building Energy Rating
Building Energy Rating (BER) grades the energy efficiency of a building
A Dwelling with a high rating will save the owner/ occupier money in energy costs.

4. Important dates for the BER
BER required for:
New dwellings that apply for planning permission on/after
1st. January 2007.
All existing buildings offered for sale or rent from 1st. January 2009.

5. Building standards & energy use
Typical for Building Regs Part L 2005
Building Regulations
2007/08
Primary Energy kWh/ m2 per year
Low/ Zero Carbon
Irish construction standard/year

6. Main factors effecting BER
Thermal insulation of the building envelope.
Heat gains through glazed openings.
Ventilation and air permeability.
Domestic hot water system and control.
Space heating control and energy required.
Lighting and internal heat gains. 6

7. 1 kWh of electricity costs 18 cent
What does BER measure?
The BER measures energy use per square meter (floor area) of the dwelling per year.
Measurement Unit
kWh/m2/yr
1 kWh of electricity costs 18 cent
Kilo watt / hour

8. Energy labelling informs the consumer of costs.
Domestic Appliances
Energy labelling informs the consumer of costs.

9. What is Building Energy Rating?
BER rating
Calculated using DEAP software.
DEAP – Dwelling Energy Assessment Procedure
BER scale (kWh/m2/yr) A1,A2,A3,B1,B2,B3 etc.
CO2 indicator (kg/m2/yr)

10. Building Energy Rating (BER) Label
Each full band is 75 kWh/m2/y and is indicated by a change of colour on the label.
FULL
BAND
Each small band is indicated by a change in the grade. Example:
A1 to A2 to A3

11. Energy Costs and BER
Cost comparasions based on average energy costs for 2007 in a 250m2 dwelling

12. Current Building Regulations
A dwelling built to the 2007/08 building regulations should achieve a:
B or C rating

13. Building Energy Rating (BER) ?
No obligatory minimum standard applies.
BER must be produced by a registered BER Assessor.
BER is valid for 10 years unless changes are made to the building.
The BER is independant of how the occupants behave in the building.
An advisory report must accompany a BER certificate 13

14. Accompanying Advisory Report
New build:
To advise owners on how to use the features in the building to maximise energy efficiency
Existing buildings:
To advise owners on the options for upgrading of building to maximise its energy efficiency

15. DEAP Computer Software
Calculating the BER
DEAP Computer Software
Download from:

16. Information required for DEAP
45 individual inputs are needed to do a BER assessment on a dwelling on DEAP
Energy used for light
Wall Heat Loss
Dwelling
Reference
Living Area
Heated to 21°
Heat gains and losses through windows
Door heat loss
Construction type
Central Heating Details
Domestic Hot Water Details
Ventilation
Heat loss through thermal bridges
Roof Heat Loss
Floor Heat Loss

17. Information required for DEAP
1. Dimensions:
The internal dimensions of the building envelope.
New dwellings can be measured from the plans.
Existing buildings may need to be surveyed.

18. Information required for DEAP
Number of chimneys/flues
2. Ventilation Details
Number of sheltered sides
Number of fans and vents
Presence of a draught lobby or porch.
Method of ventilation:
Natural or Mechanical

19. Information required for DEAP
3. Air Permeability
Sealing of the building envelope.
Blower door testing required on new dwellings.
Required to be 10 m3/(h.m2) for new 50 pa.

20. Information required for DEAP
4. Building elements (fabric heat losses)
Ceiling/Roof U-Value
Wall U-Value
Floor U-Value
Door & Window U-Values
Thermal bridging factor typical 0.11 W/m2K

21. Information required for DEAP
5. Glazed area heat losses and gains
Glazed area sizes.
Orientation.
Glazed unit U-Values
- Glazing
- Frame
Solar transmittance.

22. Information required for DEAP
6. Details of the hot water system
Level of Insulation on storage cylinder
Instant or storage system.
Insulation on pipe work.
Temperature and time controls.

23. Information required for DEAP
7. Boiler and space heating details
Boiler efficiency %
Heating controls
Radiator’s or under floor heating
Fuel used

24. Information required for DEAP
7. Boiler and space heating details contd.
Insulation on pipe work.
Temperature and time controls.
Weather compensation controls.

25. Information required for DEAP
8. Renewable energy used, e.g.
Solar Water heating
Solar photovoltaic
Geothermal energy
Wind power

26. Information required for DEAP
9. Lighting provision in the dwelling.
The percentage of energy efficient light fittings in the dwelling.

27. Information required for DEAP
10. Net space heat demand.
The heating requirements for the dwelling will depend on:
The total volume.
The living area %.
Living area is assumed to be heated to 21oC and the rest of the dwelling heated to 18oC.

28. Information required for DEAP
11. Thermal mass category of the building ranging from:
Thermally light construction e.g. timber frame
Thermally massive construction. e.g.
concrete block with hollowcore.

29. Energy rating worked example
Download the DEAP software from:
Install the software as per instructions.
Use the software to do a sample rating on the sample dwelling using the data supplied.
Vary the inputs to improve the rating.