A Gas Safe heating engineer servicing a wall-mounted combi boiler

Cost guide

How much does a gas / heating engineer cost?

Boiler and heating work is priced per installation. Only a Gas Safe registered engineer may legally work on gas appliances.

Typical day rate
£300£450
Smallest job
from £80
Priced jobs
5

Estimate your job

Pick what you need — we'll price it at current gas / heating engineer rates.

What needs doing
  • Swap a combi boiler like-for-like

    £1,800£3,000 per boiler · Includes boiler, flue, filter and a power flush.

  • Convert system to combi

    £3,000£4,800 per system · Removing the cylinder and tanks frees up a cupboard and loft.

  • Annual boiler service

    £80£140 per service · Landlords also need a CP12 gas safety certificate.

  • Power flush the system

    £400£800 per system · Priced by the number of radiators, typically £45–£70 each.

  • Fit a smart thermostat

    £120£280 per thermostat · Wireless models avoid running new cable through the house.

What each job costs

JobUnitTypical price
Swap a combi boiler like-for-likeIncludes boiler, flue, filter and a power flush.per boiler£1,800£3,000
Convert system to combiRemoving the cylinder and tanks frees up a cupboard and loft.per system£3,000£4,800
Annual boiler serviceLandlords also need a CP12 gas safety certificate.per service£80£140
Power flush the systemPriced by the number of radiators, typically £45–£70 each.per system£400£800
Fit a smart thermostatWireless models avoid running new cable through the house.per thermostat£120£280

Ex VAT. South East baseline — the calculator adjusts for your region.

Keeping the cost down

  • Check the engineer's Gas Safe ID card on site — the number is verifiable.
  • Register the boiler for its warranty within 30 days of installation.
  • Quotes in autumn are usually higher; book replacements in spring.

Common questions

How long does a boiler swap take?
One day for a like-for-like combi swap, two to three days for a system conversion.
Is a magnetic filter worth it?
Yes — most manufacturers now require one for the warranty to stand.

Ready for real numbers?

Describe the job once and vetted gas / heating engineers come back to you with priced quotes. Free, and no obligation.