Boiler hub

Fitting, fixing, or replacing a boiler

Whether you're dealing with a broken boiler, comparing brands before a replacement, or trying to decide between a combi and a system boiler, one rule applies to all of it: whoever touches the gas side of the job must be Gas Safe registered, by law.

Our guide on finding and hiring the best boiler fitters covers exactly what to check before anyone starts work, including how to verify a Gas Safe ID card. If your boiler's already broken down, our guide on what to do when you have a broken boiler covers the troubleshooting worth trying before you call anyone out.

Deciding between boiler types? Our comparison of combi boiler vs system boiler covers which suits which kind of home.

The stages of a boiler project

• Work out what's actually gone wrong — see what to do when you have a broken boiler

• Decide on boiler type, if you're replacing rather than repairing — combi boiler vs system boiler and finding the best boiler brands cover the key decisions

• Get an accurate cost estimate — our boiler installation cost calculator gives a free instant estimate

• Hire a Gas Safe registered fitter — see finding and hiring the best boiler fitters for exactly what to check

• Keep the boiler running well afterwards — see how to repressurise a boiler

Looking to find out more about boilers?

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• Why is my Worcester boiler losing pressure but no leak?

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Questions for your boiler fitter

Qualifications and Experience

• Are you Gas Safe registered? Can I see your Gas Safe ID card?

• What type of boiler would you recommend for my home, and why?

Project Specifics

• Whereabouts in my home can the boiler be fitted? (It needs to go on a sturdy wall capable of supporting its weight when filled with water)

• How long will the job take? (A like-for-like swap is typically 4-6 hours; converting a regular boiler to a combi can take 1.5-2 days)

• Will you provide an installation certificate once the work is done?

Quotes and Contracts

• Does the quote separate the cost of the boiler, labour, and any additional pipework or removal of the old unit?

• Will you ask for full payment upfront, or only after the job's complete?

Guarantees and Warranty

• Will the fitted boiler come with a manufacturer warranty, and does it include a regular service?

• What guarantee do you offer on your own workmanship?

• How often should the boiler be serviced to keep any warranty or insurance valid?