Boiler advice for UK homeowners

Good boiler advice starts with four questions: which type of boiler suits your home, what it should cost fitted, who is allowed to fit it and what to do when it goes wrong. This boiler advice page answers each one in turn and sends you to the guide or tool that goes deeper. It is written for homeowners in the UK, and each page it links to shows its sources.

Boiler advice on choosing a type

Start with your hot water, because that is what separates the types. A combi makes hot water on demand and needs no cylinder, so it suits a flat or a house with one or two bathrooms. A system boiler stores hot water in a cylinder, which suits a busy household with several taps in use at once. A regular boiler works with a cylinder and a loft tank. It often replaces an older open-vented system. Homes with no gas supply look at electric or oil instead.

Our boiler types page puts all of these side by side, with what each costs fitted, who it suits and what a quote should include. If you already know you want a combi, the gas combi boilers page is the place to start.

Boiler advice on brands and models

Once you know the type, the next choice is a make and a range. The brand matters less than the range, because every major maker sells cheaper ranges with shorter warranties and dearer ones with longer cover. Our boiler brands guide compares the main makes, shows the warranty lengths and explains the questions to put to any installer. If you are leaning towards one maker, the Vaillant boilers guide goes through that range in detail.

For individual models, the combi boiler models page shows what each popular model costs fitted.

Boiler advice on what a boiler costs fitted

Prices vary with the type, the make, the output and the job. A like-for-like swap is the cheapest. Moving the boiler or changing type adds pipework and labour. Our combi boiler prices page shows every type and model, including VAT, and the boiler installers pages show how the price changes from region to region.

If you want to spread the cost, our finance tool works out the monthly payments on an amount and a rate you choose, and it names no lender. Our VAT guide explains the rate that applies to a gas boiler.

Boiler advice on grants and help with the cost

Grants for a new gas boiler are rare. The Boiler Upgrade Scheme pays towards heat pumps, not gas boilers, and help with a gas boiler comes mainly through means-tested schemes. Our boiler grants guide explains what each scheme covers and who it is for, with a section for each of England, Wales, Scotland and Northern Ireland.

Boiler advice on who can fit your boiler

Gas work has to be done by a Gas Safe registered engineer, and you should check before anyone starts. Our Gas Safe Register guide shows how to read the ID card, what the back of it means and how to check an engineer online. When you ask for quotes, compare them on the same footing: the make and model, the warranty, what is included and who registers the installation.

Use the compare tool to put quotes side by side and the quote checker to see what each one leaves out. If you want installers to come to you, get free quotes from Gas Safe engineers who cover your postcode.

When your boiler shows a fault code

A fault code is the boiler telling you something has stopped it working. The first step is always to read the code, find your make and model and look up the code in your manual. Our guide to boiler fault codes explains how to do that and which checks are safe. We also cover the commonest codes in detail: Vaillant F22 and Ideal F1 for low pressure, and Vaillant F28 and Ideal L2 for flame and ignition faults.

If you ever smell gas, leave the property and call the National Gas Emergency Service. The fault code guides give the number.

When to think about replacing a boiler

A single fault isn’t a reason to replace a boiler. Several faults in a winter, parts that are hard to find or repair quotes that approach the price of a new boiler are. When that point comes, price it before you decide. A like-for-like swap is the cheapest option, and the prices page shows what to expect. Ask an engineer for a written quote that names the make, model and output, and ask what they make of the old boiler’s faults. That gives you something to set against our prices.

Official sources worth bookmarking

When the stakes are a gas appliance or a grant, go to the original. The Gas Safe Register lets you find and check an engineer. The GOV.UK Boiler Upgrade Scheme page lists what that scheme pays, and Ofgem’s ECO page covers the scheme for low income households. For fault codes, use your own maker’s pages, such as Vaillant’s fault code page and Ideal’s fault code FAQ, and your manual.

How we keep this boiler advice honest

Every guide is written from the manufacturer’s or an official page that we read before writing, and it links to it so that you can check. Prices come from published UK sources and are shown with VAT. Our pricing method explains how, and you can report a price that doesn’t match a quote you have had. The site is published by Leads Do Work Ltd, and our disclosure page says how it is paid for.

This page is general advice and not a substitute for a survey by a Gas Safe engineer.