Fuel for Thought
All boilers are given a rating for energy efficiency.
Boiler efficiency tests are subject to a degree of measurement uncertainty. Consequently, small differences in the efficiency values calculated from them are not significant and should not be relied on when comparing boilers. Statistical analysis suggests that if two boilers have SEDBUK values 3 percentage points apart then there is 95% confidence that the boiler with the higher value is more efficient.
The table below shows the effect of variation in boiler efficiency on annual running costs for typical domestic properties in the UK with central heating and a gas boiler. Although the costs in the table are typical for the type of property, there will always be wide variations in individual cases due to climate, exposure, occupancy patterns, heating controls, insulation, and other factors.
Typical Annual Fuel Costs |
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| Seasonal efficiency | Flat | Bungalow | Terraced | Semi-detached | Detached | |
| Old boiler (heavy weight) | 55% | £267 | £341 | £354 | £397 | £550 |
| Old boiler (light weight) | 65% | £231 | £293 | £304 | £340 | £470 |
| New boiler (non-condensing) | 78% | £197 | £249 | £258 | £289 | £396 |
| New boiler (condensing) | 88% | £178 | £224 | £232 | £259 | £355 |
Visit www.boilers.org.uk to find ratings for current boilers.