Construction Studies
An introduction to
Building Energy Rating
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.
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.
Building standards & energy use
Primary Energy kWh/ m2 per year
400
350
Typical for Building
Regs Part L 2005
300
250
Building
Regulations
2007/08
200
150
Low/ Zero
Carbon
100
50
0
1972
1979
1982
1992
2002
Current
Regs
2010 ?
Irish construction standard/year
2016 ?
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.
What does BER measure?
• The BER measures energy use per
square meter (floor area) of the
dwelling per year.
• Measurement Unit
kWh/m2/yr
Kilo watt / hour
1 kWh of
electricity
costs 18 cent
Energy Labelling
Domestic Appliances
Energy labelling informs the consumer of costs.
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)
Building Energy Rating (BER) Label
• Each full band is 75
kWh/m2/y and is
indicated by a change
of colour on the label.
• Each small band is
indicated by a
change in the grade.
Example:
A1 to A2 to A3
FULL
BAND
Energy Costs and BER
• Cost comparasions based on average
energy costs for 2007 in a 250m2 dwelling
Current Building Regulations
• A dwelling built to the 2007/08 building
regulations should achieve a:
• B or C rating
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
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
Calculating the BER
DEAP Computer Software
Download from:
http://www.sei.ie/index.asp?docID=1073
Information required for DEAP
45 individual inputs are needed to do a BER
assessment on a dwelling on DEAP
Property address
MPRN (electricity
meter number)
Planning reference
number
#
Chimneys
# Permanent vents
# flues
# fluleless gas fires
# Sheltered sides
Draught lobby
Structure type
Draughtstripping
Ventilation method
Floor Area
W all Area
W all U-value
Door Area
Door U-value
Factor for thermal bridging
W indow Area
W indow Description
W indow Frame Material
W indow Orientation
W indow Overshading
Heat
loss through
W ater storage type
thermal
bridges
W
ater storage
volume
Insulation type
Solar water heating
Low energy lighting %
Living area %
Thermal mass category
Heating
controls
Heat
gains and
Heat emitter
losses
# Central heating pumps
through
Boiler interlock
Space heating
fuel
windows
Main space heating
system efficiency
2nd space heating fuel
2nd space heating
efficiency
W ater heating system
fuel
Energy used Dwelling
Wall Heat
Loss for light
Reference
Domestic Hot
Ventilation
Water Details
Construction
type
Living
Area
Roof Heat
Door
heat
loss to 21°
Heated
Loss
Central
Heating
Details
Floor Heat
Floor U-value
Insulation on primary
Loss
Roof Area
Roof U-value
pipework
Thermostat on cylinder
W ater heating system
efficiency
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.
Information required for DEAP
2. Ventilation Details
Number of chimneys/flues
Number of fans and vents
Number of sheltered sides
Presence of a draught lobby or porch.
Method of ventilation:
Natural or Mechanical
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
dwellings @ 50 pa.
Information required for DEAP
4. Building elements (fabric heat losses)
• Wall U-Value
• Ceiling/Roof U-Value
• Floor U-Value
• Door & Window U-Values
• Thermal bridging factor typical 0.11 W/m2K
Information required for DEAP
5. Glazed area heat losses and gains
• Glazed area sizes.
• Orientation.
• Glazed unit U-Values
- Glazing
- Frame
• Solar transmittance.
Information required for DEAP
6. Details of the hot water system
Instant or storage system.
Level of Insulation on storage cylinder
Insulation on pipe work.
Temperature and time controls.
Information required for DEAP
7. Boiler and space heating details
Boiler efficiency %
Fuel used
Heating controls
Radiator’s or under floor
heating
Information required for DEAP
7. Boiler and space heating details contd.
Insulation on pipe work.
Temperature and time controls.
Weather compensation controls.
Information required for DEAP
8. Renewable energy used, e.g.
• Solar Water heating
• Solar photovoltaic
• Geothermal energy
• Wind power
Information required for DEAP
9. Lighting provision in the dwelling.
• The percentage of energy efficient light
fittings in the dwelling.
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.
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.
Energy rating worked example
• Download the DEAP software from:
http://www.sei.ie/index.asp?docID=1073
• 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.