Boiler reviews: FAQs

Buying a new boiler is an expensive process

Buying a new boiler may include paying for new gas and water pipes, boiler controls and boiler installation costs

How much will I pay for a new boiler?

Boiler prices range from £500 for a basic gas model up to £2,200 for a large external oil boiler. But you'll also need to pay for installation. 

You can use our interactive boiler finder to compare the price of new boilers.

The English Boiler Scrappage scheme recorded the cost of more than 118,000 new boiler installations carried out in England in 2010. The average cost of getting a new boiler installed was £2,459. You might expect that to be equivalent to £2,582 now that VAT is at 20%. 

Boilers installed by energy suppliers cost the most (£3,169) and boilers installed by small local companies the least (£2,347). The average boiler installation price was higher in London and the south of England and lower in the Midlands and north of England.

How reliable are boilers?

In our 2012 survey of boiler owners, we discovered that two thirds who'd bought a boiler since April 2005 have experienced some kind of fault, which meant their boiler didn't heat their hot water or radiators. 

Not all of these faults needed repairing, but 32% of boiler owners have had a visit from a boiler repairer. 

Discover which brands make the most reliable boilers gas and oil boilers to avoid these inconvenient visits.

The most frequent problem, a frozen condensate drainage pipe, experienced by 11% of owners, is caused by poor installation (see below).

Boilers back of an envelope

You can work out how much you could save on your gas bill by comparing the efficiency of your new and old boilers

Could I save money on my fuel bill?

This depends on how efficient your current boiler is and how much you currently spend on fuel.

It's estimated that the average efficiency of boilers in UK homes is about 60%. This means they waste up to 40% of the heat they generate in the form of hot flue gases. 

If you swap a boiler that is 60% efficient for one that is 90% efficient you might expect to cut the amount of gas you use by up to 30%.

You'll need to use the figures from your current fuel bills to find how much gas or oil you use and what it costs.

Visit the Sedbuk website to find out how efficient your existing gas or oil boiler is. If it's not on there you can assume it's old enough for you to save a lot on fuel by upgrading.

sedbukchart

Sebuk ratings are now presented as a percentage - here's how the new percentages match up to the old-style ratings

What does the Sedbuk efficiency rating mean?

Sedbuk stands for 'seasonal efficiency of a domestic boiler in the UK' and is given as a percentage score. 

This score is an estimate of efficiency when the boiler is installed under typical conditions in Britain, taking into account climate, housing conditions, occupancy patterns, and boiler or heating controls. You'll see it stated as 'SAP 2005' or 'SAP 2009' depending on which standard assessment procedure was used to calculate the efficiency.

This score, which was developed under the UK Government's Energy Efficiency Best Practice Programme (with the help of boiler manufacturers) lets you compare the efficiency of different boiler models.

Traditionally, conventional boilers ranged from around 66% to 81% efficient, while condensing boilers are between 85% and 91% efficient (SAP 2005). 

Building regulations now require all newly installed boilers to be at least 88% efficient (SAP 2009). Boilers with a score below 88% are still being sold but these will disappear over time as new models come to the market.

We include the efficiency rating as part of our boiler reviews.

What happened to A-D boiler energy labels?

The Sedbuk efficiency rating is now a percentage score and this score has replaced the old A-D labels for boilers. The letter labels have been withdrawn to avoid confusion with the European energy labels, which use similar ratings but are based on different principles. 

You can find the Sedbuk efficiency rating of all current boilers on the government's boiler efficiency database.

My boiler's condensate pipe has frozen. What can I do?

To prevent freezing, boilers retain condensate water and then let it out in a gush. However, particularly cold weather can still cause the water in the condensate pipe to freeze. This is especially true if the condensate pipe is external. 

If your condensate pipe is frozen, your boiler will probably switch itself off - exactly the opposite of what you need in freezing weather. To get your boiler going again, try the following steps.

  • Use warm, but not boiling, water to unfreeze the pipe's contents. This is only a temporary fix if the weather remains cold. 
  • Lag the pipe with insulating material.
  • If the pipe is at a shallow angle or very narrow, it may need to be reinstalled. The larger and more vertical the pipe is, the better. 

More on this...

Which? works for you © Which?