Do I Need New Radiators for a Heat Pump?
Probably not all of them. Heat pumps run at lower flow temperatures than gas boilers, so some radiators may need to be larger. But in most homes, only 2-4 radiators need upgrading — not the whole house.
At a glance
- Typical radiators to upgrade
- 2–4
- Cost per radiator (fitted)
- £200–£400
- Underfloor heating needed?
- No
- Rooms most likely to need upgrade
- Living room, bathroom
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Why radiator size matters
Gas boilers heat water to 60–80°C. Heat pumps work best at 35–50°C. At lower temperatures, each radiator gives off less heat, so some rooms might not get warm enough with their current radiators. The solution is usually to fit larger radiators in those specific rooms — not to replace every radiator in the house.
Which radiators typically need upgrading
The most common rooms needing bigger radiators are the living room (often the largest room) and bathrooms (often have small towel rails). Bedrooms and kitchens usually have adequate radiators already. If you have underfloor heating in any rooms, those are already perfect for heat pumps — no changes needed.
What it costs
A replacement radiator typically costs £200–£400 fitted, including the radiator and labour. If you need 3-4 radiators upgraded, budget £600–£1,600. Some installers include a set number of radiator upgrades in their heat pump quote — always check what's included.
Alternatives to new radiators
Before replacing radiators, your installer should check if running the heat pump at a slightly higher flow temperature (45-50°C) keeps your home warm enough. This reduces efficiency slightly but avoids the cost of new radiators. Adding insulation also reduces the heat output needed from each radiator.
How we calculate estimates
Our estimates use published data from the Energy Saving Trust, Ofgem tariff caps, and MCS installer pricing. We model savings based on your home size, insulation level, and current heating system. All figures are indicative — your actual costs will depend on your installer's survey and quote.