Gas & Heating

What Does a Gas and Heating Engineer Do?

Gas and heating engineers install, service, and repair gas appliances and central heating systems in domestic properties. This includes boiler installation and replacement, annual boiler servicing, central heating system installation and upgrades, fitting thermostats and smart heating controls, repairing or replacing radiators, and diagnosing faults such as no hot water, cold spots in radiators, or pressure loss. Some engineers also install and maintain unvented hot water cylinders and heat pump systems.

All gas work in the UK must by law be carried out by an engineer registered with the Gas Safe Register — the official list of legally permitted gas engineers. It is illegal for an unregistered person to work on gas appliances, and doing so puts lives at risk. Always check the engineer's Gas Safe ID card before any work begins, and verify it on the Gas Safe Register website.

Typical Costs in the UK

Gas Safe engineers typically charge £50–£90 per hour. An annual boiler service costs between £70 and £120. Replacing a standard combi boiler, including installation and flue, typically ranges from £1,500 to £3,000 depending on the brand and model. A full central heating system installation in a three-bedroom house — including a new boiler, radiators, and pipework — can range from £4,000 to £8,000. Power flushing a system to remove sludge typically costs £300–£600.

How to Choose the Right Engineer

Verify Gas Safe registration before booking — this is non-negotiable. Beyond that, look for engineers accredited by boiler manufacturers (such as Worcester Bosch Accredited Installers or Vaillant Advanced Installers), as accreditation often comes with extended warranty options. Check online reviews and ask whether the quote includes parts, labour, and any required Gas Safe certificates. Reputable engineers will carry out a proper heat loss calculation before recommending a boiler size, rather than simply replacing like-for-like without assessment.