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How to Buy the Best Boiler

By Matthew Knight

Expert advice on how to find the best boiler for your home. Once you are clued up, take a look at our boiler reviews to make sure you get a reliable Best Buy.

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Boiler video buying guide

A new boiler is likely to be one of the most expensive household purchases you'll make - so it's important to choose the best new boiler for your home, at the right price. Watch our video, above, to get top tips on buying the best boiler for you.

Use our independent reviews to find out which new models we recommend as Best Buy boilers. Our Best Buy boilers are decided after feedback from people who own them and expert heating engineers. 

New boiler checklist

First, you need to decide which type of new boiler to go for. Here's what you should consider:

Fuel type

Most UK households have a gas heating system equipped with a gas boiler. But if you're one of the the estimated 4.3m households not connected to the UK's gas network, there are alternatives. These include fitting an oil boiler, liquid petroleum gas or LPG boiler, or a wood-burning stove fitted with a back boiler. 

See our home heating systems guide or heating oil guide for more information. 

Boiler type

If you have a gas heating system with a gas boiler, you need to choose between:

  • a combination (or combi) boiler, which provides heat for your radiators and domestic hot water on demand 
  • or a heat-only boiler, which is connected to a hot water storage system. 

Our combi boiler guide will help you decide which type of boiler is best for you. Alternatively, ask a professional installer for their opinion.

Boiler efficiency 

If you have gas central heating, your boiler will account for around 60% of your home's CO2 emissions, according to the Energy Saving Trust. This makes your choice of boiler a key priority if you're looking to cut your energy bills and carbon footprint.

Boiler efficiency is an integral part of our independent boiler reviews. You can filter our boiler reviews by efficiency rating using the box on the left of our boiler reviews.

Heating controls

Heating controls let you take charge of when, where and at what temperature your heating is operating. It’s a good way of managing your heating costs, as you can ensure that your heating is only on certain rooms at certain times. 

When you come to replace your boiler, it may be a good time to install a heating control system. Find out more with our guide to the best boiler controls.

Boiler installation 

Don't attempt to install a replacement boiler yourself - leave it to the professionals. Find a competent heating engineer on the Gas Safe Register (the gas registration scheme previously run by Corgi) to do the work for you. To be sure of a tradesperson's credentials, ask to see their Gas Safe Register ID card or run a check on the Gas Safe Register website.

Which? Trusted Traders,  is the best place to start to find a high quality Which? endorsed heating engineer for your installation. Always get at least three quotes for boiler installation and make sure they include all costs including any call-out fees. Don't be taken in by any headline discount figures - look at the total price of the boiler and labour charges.

You may find that some installation companies, including services offered through British Gas and other energy companies, will suggest a replacement boiler for you rather than allowing you to choose your preferred model. This is because many heating engineers are incentivised to install particular brands. 

So it's vital that you check your heating engineer's recommendation against the views of their peers - which is where we can help. We surveyed 179 Which? Trusted Trader heating engineers to find out what they really think of the different boiler brands on the market. You can use our research to make sure you pick the best boiler brand for your home. Check out the best boiler brands, then make your wishes clear to the installer from the outset.


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