The following section details the approach to deriving the correct efficiency for solid fuel appliances based on fuel type and efficiency data available for the appliance.
1) If the appliance fuel type as per guidance here matches the test data fuel type then the gross efficiency is used if it is shown on the test certificate or on HARP.
Example 1:
2) If the appliance fuel type as per guidance here matches the test certificate fuel type but the test certificate only shows the net efficiency then the net/gross conversion described in Appendix E must be applied (see Table 4.32).
Example 2:
3) If the appliance fuel type is solid multifuel then the Assessor should consider the average efficiency from available solid fuel test data. This may be a single efficiency for a single fuel type or multiple efficiencies for multiple fuel types. The data could be from HARP or from other accredited sources. If the test data specifies gross efficiencies, such as on HARP, then the average of these can be used in DEAP. If the test data efficiencies are net, then these are averaged and the solid fuel net/gross conversion of 0.94 set out in table 4.32 must be applied.
Example 3:
This appendix sets out the method to be used to determine the gross seasonal efficiency for gas, oil, or solid fuel room heaters. BER assessors are encouraged to source efficiency data for these room heaters from the HARP database. Declared seasonal efficiencies acceptable for UK SAP calculations are also acceptable for DEAP calculations provided suitable substantiating evidence (such as a test certificate) is supplied.
The EPREL database may be used as a source of efficiency for solid fuel room heaters.
Test results obtained by one of the recognised methods given in Table 4.29, Table 4.30 and Table 4.31 may be used to establish a seasonal efficiency for DEAP calculations.
| Test Standard | Description |
|---|---|
| IS EN 613:2000 | Independent gas-fired convection heaters |
| I.S. EN 613:2021 | Independent closed-fronted gas-fired type B11, type C11, type C31 and type C91 heaters |
| IS EN 13278:2013 | Open-fronted gas-fired independent space heaters |
| IS EN 1266:2002 | Independent gas-fired convection heaters incorporating a fan to assist transportation of combustion air and/or flue gases |
| BS 7977-1:2009 | Specification for safety and rational use of energy of gas domestic appliances. Part 1: Radiant/convectors |
| BS 7977-2:2003 | Specification for safety and rational use of energy of gas domestic appliances. Part 2: Combined appliances: Gas fire/back boiler |
| Test Standard | Description |
|---|---|
| OFS A102:2004 | Oil fired room heaters with atomising or vaporising burners with or without boilers, heat output up to 25 kW |
| Test Standard | Description |
|---|---|
| I.S. EN 16510-1 | Residential solid fuel burning appliances - Part 1: General requirements and test methods |
| I.S. EN 16510-2-1 | Residential solid fuel burning appliances - Part 2-1: Roomheaters |
| EN 13229 | Inset appliances including open fires fired by solid fuels - Requirements and test methods |
| EN 13240 | Roomheaters fired by solid fuel - Requirements and test methods |
| I.S. EN 14785:2006 | Residential space heating appliances fired by wood pellets - Requirements and test methods |
| EN 16510-2-6 | Residential solid fuel burning appliances - Part 2-6: Mechanically by wood pellets fed roomheaters, inset appliances and cookers |
Efficiency test results are normally calculated using the net calorific value of fuel. Before a declaration can be made, conversion to gross must be carried out by multiplying the efficiency by the appropriate conversion factor given in Table 4.32 below if test results are not based on the gross calorific values of the relevant fuel.
| Fuel | Net-to-gross conversion factor Description |
|---|---|
| Natural gas | 0.901 |
| LPG (propane or butane) | 0.921 |
| Oil (kerosene or gas oil) | 0.937 |
| Biodiesel or bioethanol | 0.937 |
| Coal | 0.97 |
| Anthracite or manufactured smokeless fuels | 0.98 |
| Wood fuels | 0.91 |
| Solid multi-fuel | 0.94 |
Manufacturers’ declarations so calculated should be accompanied by the following wording and should be accompanied by the associated test certificates from an accredited laboratory.
“The gross seasonal efficiency of this appliance has been measured as specified in [insert appropriate entry from Table 4.29 or Table 4.30 or Table 4.31] and the result is [x]%. The gross calorific value of the fuel has been used for this efficiency calculation. The test data was certified by [insert name and/or identification of notified body]. The efficiency value may be used in the Irish Government’s Dwelling Energy Assessment Procedure (DEAP) for energy rating of dwellings.”
Where net efficiencies are identified from test data, they must be converted to gross efficiencies before use in DEAP assessments.
The efficiency of solid fuel room heaters may be sourced from the EPREL database. The useful energy efficiency (at nominal heat output) must be converted to the gross calorific value for entry in DEAP. The datasheet from EPREL should be downloaded from the database and uploaded to DEAP in the evidence file.
The preferred source of efficiency data is HARP and certified data may also be used. However, efficiencies for solid fuel heaters without boilers can be sourced from the HETAS listing. Use the gross efficiency if listed, or else use table 4.32 to convert to a gross efficiency from net efficiency. Apply rules from the efficiency data for solid fuel appliances section to identify the correct efficiency dependent on fuel type. Do not use HETAS to source efficiencies for DEAP for boilers or appliances with back boilers.