Heat Pump Replacement & Upgrades

Two kinds of replacement

Replacing an old heat pump

Heat pump technology has moved on quickly. A unit fitted ten or more years ago will have a lower seasonal efficiency than a modern equivalent, and parts may be hard to source. If your system is struggling, noisy, or expensive to run, replacing it with a current model often pays back through lower bills. A good installer reuses your existing cylinder, pipework and radiators wherever they are sound, so a like-for-like replacement is usually quicker and cheaper than a first installation.

Converting a boiler to a heat pump

The larger market is homeowners replacing an old gas, oil or LPG boiler. This counts as a first heat pump installation, so it qualifies for the £7,500 Boiler Upgrade Scheme grant, rising to £9,000 for oil and LPG homes from July 2026. The installer removes the old boiler, fits the heat pump and cylinder, and upgrades radiators only where the heat loss survey shows it is needed. See our installation page for the full process.

Signs your heat pump is on the way out

• Running costs creeping up year on year despite stable energy prices.
• The system takes much longer to reach temperature than it used to.
• Repeated fault codes or call-outs.
• Grinding, rattling or louder than normal noise from the outdoor unit.
• Visible ice build-up that does not clear, or signs of a refrigerant leak.
• The unit cannot hold target temperature on the coldest days.

Upgrades short of full replacement

Not every tired system needs replacing. Sometimes the gain comes from better controls, weather compensation, a buffer tank, or correcting an undersized radiator that has always held the system back. During the survey a good installer identifies whether a targeted upgrade will restore performance or whether replacement is the better value decision. The installers we match you with should not push a full replacement where a sensible upgrade will do.

What it costs

Replacing an existing heat pump typically costs less than a first installation because much of the supporting hardware is reused. Boiler-to-heat-pump conversions are priced like a new installation but benefit from the grant. Your chosen installer quotes on survey, with a clear fixed price and any grant deduction shown. For running cost expectations, see our running costs guide.