Boilers: How we assess boilers
Buying a new boiler is expensive and can be intimidating - how do you know what boiler you need and which one is best? Even worse, the cost of the boiler is often eclipsed by the price of installation – plus there are safety issues to consider - so it’s crucial that you make the right choice for both the product and the service.
Does Which? test boilers?
We used to, but we no longer do. These are the reasons why:
A boiler is sized to suit your home's hot water demands
Boiler performance depends on your central heating system
A boiler is an unusual product; unlike the majority of other home appliances you can buy, its performance is not entirely dictated by the product itself - it's heavily influenced by the heating system that you connect it to; if the system is poorly designed or has inadequate controls the boiler will not perform as well as it could.
Every home should be individually assessed for its heat and hot water requirements. The type of performance tests that we could conduct in a lab a would not give us the answer to the main question that you want answered; 'Which is the best boiler for my home?'.
Boiler efficiency is tightly controlled
Improving the energy efficiency of the UK's homes is a major target for the government, and as part of its efforts it has imposed strict regulations on the energy efficiency of new boilers. The new boilers installed must be 88% or more efficient to comply with Building Regulations.
But there's a limit to how efficient a gas or oil boiler can be, giving most people little choice between the most and least efficient boiler. Efficiencies typically range from 88.3% to 89.7% across all gas combination boilers. This range is so narrow that you wouldn't expect to see a difference in your gas or oil consumption if you were to choose the most over the least efficient.
Claimed efficiencies for new boilers are generally accurate
Our previous tests of boilers showed that the efficiency claims made by manufacturers, which are tested by an independent lab according to a strict standard protocol, are generally accurate (within the limits of the testing method).
Feedback from you
Feedback from our members indicates that what you really want to know is whether a boiler is reliable and which brands to consider.
How does Which? research gas boiler satisfaction and reliability?
To help you choose a boiler, we got the lowdown on popular boiler brands by asking 5,758 owners – all Which? members - about their experiences of their boilers.
In May and June 2011, we asked about the gas and oil boilers Which? connect online panel members had installed within the previous six years.
The Which? boiler brands reliability score
We asked Which? members about their brand of gas or oil condensing boiler, and to tell us the faults they'd experienced and whether they had ever had a repair.
The Which? reliability score is based on the proportion of boilers that have had repairs, adjusted by age to ensure that all brands are compared on an equal basis.
We need at least 50 responses per brand to calculate a reliability score.
The reliability scores include the brands of gas boilers owned by more than 85% of the gas boilers and two thirds of the oil boilers owned by our members; it covers all of the major brands. Only brands with less than 2% of market share are too small to be included in our reliability survey.
The Which? boiler brands customer score
We also asked them to assess how satisfied they were and how likely they would be to recommend their brand of gas condensing boiler (regardless of their experience of getting the boiler installed). These two questions form the basis of the Which? customer satisfaction score
Choosing Best Buys
Only boiler brands that are above average for both customer score and reliability can qualify to be a Which? Best Buy.
Trial Which? today to find out which boilers we rated as Best Buys, or log in if you already have member access.
