Data should be entered as accurately as possible, although it is unnecessary to go beyond three significant figures (and some product data may only be available to lesser precision). In some cases, there are a limited number of data entry options available. Unless otherwise stated in SEAI guidance, the most prevalent option should be chosen. As an example, where a dwelling has 100m2 solid ground floor and 75m2 suspended ground floor, ’No‘ is selected under the entry “Is there a suspended wooden ground floor?”.
BER assessors are required to adhere to the BER assessor’s Code of Practice when publishing BER assessments on the National Administration System (NAS). Reference data tables are provided for use when specific product or system performance information is not available. Specific performance information, as outlined below, should be used in preference to data from the tables, particularly for new dwellings. BER Assessors are expected to make reasonable efforts to ascertain non-default values rather than opting for default values. The use of defaults in New Final BERs is limited. Appropriate certification and supporting documentary evidence is required to account for energy performance characteristics in the BER in cases where defaults do not apply.
While there are a number of readily available sources for performance data entered into DEAP (such as HARP or other suitable databases), assessors may occasionally need to use other sources to substantiate DEAP data entries. The acceptable data sources often depend on the product or appliance and are detailed in relevant sections throughout this document. Further guidance on the following sources of performance data is available in the DEAP Survey Guide:
U-values – walls, floors, roofs
U-values should be calculated on the basis of the actual construction for new and existing dwellings. Section 2 details the relevant standards and requirements for U-value calculations and supporting evidence.
Window data
Window U-values and g-values (total solar energy transmittance) should be obtained from certified data or calculated to standards outlined in Section 2. Both U-values and g-values are needed when supplying non default data. For light transmittance, only the values in Table 2.31 are to be used. The frame factors (representing the glazed fraction of the window) should be taken from test certificates. If frame factors are not available on test certificates, then the defaults in Table 2.32 are used. Section 2 details the requirements for assessment of curtain walling for DEAP assessments.
Thermal bridging - linear thermal transmittance
There are a number of options for including the effect of linear thermal bridging in DEAP:
Internal heat capacity
Internal heat capacity of the dwelling is estimated on the basis of the extent of thermally heavy construction relative to total floor area. Thermal mass categories should be determined in accordance with Section 2 using Table 2.41 or Table 2.43. The dwelling thermal mass is applied to the space heating and cooling demand calculation.
Boiler efficiency – gas and oil
Boiler efficiency should be preferably sourced from the Home-Heating Appliance Register of Performance (HARP) database, or alternatively from certified data as described here. Default values from Table 4.5 must be used if data is not available from these sources.
Boiler efficiency – solid fuel
Boiler efficiency should be preferably taken from the HARP database, or alternatively from certified data. Default values from Table 4.4 may also be used as specified in Section 4.
Heat pump efficiency
The heat pump efficiency is calculated in DEAP, based on data taken from the HARP database, EcoDesign data & declarations5, or certified test data. Default values from Table 4.4 may be used in the absence of non-default. Section 4 provides further detail on input data for heat pumps.
5 Additional evidence may be required for non-default data not covered in Ecodesign Product Information requirements
Efficiency of gas/oil/solid fuel fires and room heaters
Efficiency should be taken from the HARP database or accredited data as specified here (gas, oil, and solid fuel). Default values from Table 4.4 may also be used. Efficiency for solid fuel room heaters may also be sourced from the EPREL database.
Air leakage - pressure test (also called permeability test) result
Air leakage pressure test results can be used instead of the default air infiltration calculation. All New Final BERs require an air pressure test.
An air permeability design value may be used for new dwelling provisional BERs, subject to verification when the dwelling is built:
Standing loss – cylinders, thermal stores and CPSUs (includes both gas and electric CPSUs)
The manufacturer's declared loss, obtained in accordance with an applicable Irish or British Standard, expressed in kWh/day can be used instead of the calculated storage loss. Section 5 provides background on the hot water storage losses calculated in DEAP. The manufacturer’s declared storage loss may also be sourced from the EPREL database.
Solar collector performance
The zero-loss collector efficiency and the collector's linear heat loss coefficient can be used if obtained from the HARP database or test results as outlined in Section 8. Defaults are also available there.
Specific fan power
Specific fan power for the following mechanical ventilation systems may be used in place of the default values in Table 3.7, subject to the guidance in Section 3:
Technical specifications
A reference to a technical specification is to the latest edition (including any amendments, supplements, or addenda) current at the date of publication of this document. However, if this version of the technical specification is subsequently revised or updated by the issuing body, the new version may be used as a source of guidance provided it continues to address the relevant requirements of the regulations.
Where a European Commission regulation or communication for that regulation references a specific standard, that version of the standard should be used until such time as any future communication refers to an alternate, or a harmonised standard is developed.
Cooling Seasonal Energy Efficiency Ratio (SEER)
The cooling SEER is relevant where a fixed cooling system is installed (that is air conditioning or a heat pump system). SEER values and sources are defined in Section 6. Cooling demand is only calculated in DEAP where a fixed cooling system is installed.
Default values may be used when assessing existing dwellings subject to the guidance in Section 2. Non-default values must be used when sufficient substantiating evidence is available.
BER assessors are required to complete a site survey in accordance with the DEAP survey guide for existing and ’New-final’ BERs. BER assessors are required to visit the dwelling to collect the data for the assessment and may also review plans and specifications for new or existing buildings. Plans and specifications are particularly useful in providing supplementary information not available from the site survey.
The energy performance of buildings is typically expressed as an asset rating, based on calculated energy use under standardised occupancy conditions or an operational rating, based on metered energy. DEAP uses the building fabric and heating and cooling system details to calculate the dwelling energy use and is therefore an asset rating. DEAP assumes the dwelling is used by standard, notional or typical occupants and is not affected by the current occupants, for example the heating system operating hours and temperature set points are fixed.
The dwelling forms or types identified in DEAP are:
The classification of a house as detached, semi-detached, or terraced depends on how it adjoins the neighbouring buildings. A side is considered attached if more than half of its area adjoins a heated space. Otherwise, it is not attached for the purposes of identifying dwelling type.
For the purpose of a DEAP assessment, a maisonette is a dwelling on two or more storeys, forming part of a larger building, and located below or above another building unit. A maisonette has its own direct entrance from outside the building.
DEAP allows the BER assessor, with guidance from the client, to record the reason(s) the BER assessment is carried out. The options under this ’Purpose of rating‘ category are:
DEAP enables users to calculate the following results, both total and per m2 of total floor area. All of these relate to the assumed standard occupancy; the energy consumption patterns of real occupants vary widely.
DEAP automatically calculates the standardised number of occupants in the dwelling (N) as follows:
TFA is the total floor area [m2].
Delivered energy, in kWh/year: This corresponds to the energy consumption that normally appears on the energy bills for the assumed standardised occupancy and end uses considered.
Primary energy, in kWh/year: This includes delivered energy, plus an allowance for the energy ’overhead‘ incurred in extracting, processing, and transporting a fuel or other energy carrier to the dwelling. The generation efficiency of power stations is included.
Carbon dioxide emissions, in kg CO2 per year: Emissions are calculated on the basis of primary energy consumption; emissions at power stations associated with the dwelling’s electricity use are included.
Costs: Current fuel costs may be calculated using the delivered energy for each fuel type in the ‘Results’ tab along with up-to-date domestic fuel cost, from the SEAI Domestic Fuel Cost Comparison available on the SEAI Website.