Heating measures introduction

For any heating system the performance obtained (in terms of running costs) will depend upon a number of parameters. The main parameters, and how they influence running costs, are tabulated below.

For fossil fuel boilers the above parameters will affect the overall operating efficiency to different extents. Therefore, in order to allow different boilers to be compared, an index - SEDBUK - has been developed under the Government's Energy Efficiency Best Practice Programme with the co-operation of boiler manufacturers, and provides a basis for fair comparison of the energy performance of different boilers.

SEDBUK is the average annual efficiency achieved in typical domestic conditions, making reasonable assumptions about pattern of usage, climate, control, and other influences. It is calculated from the results of standard laboratory tests together with other important factors such as boiler type, ignition arrangement, internal store size, fuel used, and knowledge of the UK climate and typical domestic usage patterns.

For estimating annual fuel costs SEDBUK is a better guide than laboratory test results alone. It can be applied to most gas and oil domestic boilers for which data is available from tests conducted to the relevant European standards. The SEDBUK method is used in SAP.

Because of these factors, it is not possible to give a single value for the running cost or carbon emissions. However, in order to gain some understanding of how different heating systems compare, the table below has been prepared. The values in this table have been calculated using the BREDEM 12 (BRE Domestic Energy Model), which is the basis for the SAP energy rating method. A typical heating pattern was used, with the whole house heated to a good standard. Then for both the cash and the carbon emissions, two figures have been caluculated, representing the running cost and carbon emissions that would typically result if the house were insulated to different standards as follows:

Lower figure - insulated cavity walls (U=0.47), 270mm loft insulation (U=0.16) and a 75mm hot water tank jacket.

Higher figure - no loft insulation (U=2.3), solid walls (U=2.1), no hot water tank insulation

Source BRE

The running costs and Carbon emissions from these technologies is included here for comparative purposes - the technologies are considered in more detail in the section on Renewable Technologies.

Technical guidance available

GIL31 - Building Research Establishment Domestic Energy Model (BREDEM)

General guidance for choosing heating systems is found in:

CE11 'Benefits of Best Practice: Heating and Insulation'
CE29 'Domestic heating by oil: boiler systems'
CE30 'Domestic heating by gas: boiler systems'
CE47 'Domestic heating by solid fuel: boiler systems'
CE52 / GIL74 'Domestic Condensing Boilers - The Benefits and the Myths'
CE54 'Whole House Boiler Sizing Method for Houses and Flats'
CE51 / GIL59 'Central Heating System Specifications (CHESS) - year 2008'
GPG345 'Domestic heating by electricity'