Do You Need Bigger Radiators for a Heat Pump? | EcoSphere Energy
Installation Guide · Heat Pump Efficiency
Do You Need Bigger Radiators for a Heat Pump?
Heat pumps run at lower flow temperatures than gas boilers. In some homes, existing radiators are fine; in others, some upgrades are needed to maintain comfort. Here’s what you need to know.
How Heat Pumps Differ from Gas Boilers
Understanding flow temperatures is the key to knowing whether your radiators need upgrading.
Gas Boiler: 70–80°C
Gas boilers typically heat water to 70–80°C. Radiators sized for these temperatures will be undersized at heat pump flow temperatures, resulting in a colder room.
Heat Pump: 35–55°C
Air source heat pumps work most efficiently at 35–45°C. They can go higher (up to 55–60°C) but every 5°C increase reduces efficiency by around 8–10%.
The Solution
Either upgrade radiators to larger ones, add more radiators, or add underfloor heating in key rooms. Our heat loss survey identifies exactly what your home needs.
Which Rooms Typically Need Upgrading?
Not every room will need a radiator change. Our heat loss survey identifies the specific rooms where upgrades will make a difference.
Living Rooms
Often have the biggest heat demand. Lounge radiators are commonly undersized for heat pump temperatures and may need upgrading to double-panel double-convector (K2) or larger single panels.
Bathrooms
Towel rails are often fine — they can run at 50–55°C without efficiency loss. A bathroom with a small panel radiator may benefit from an upgrade, but towel rails rarely need replacing.
Bedrooms
Bedrooms have lower heat demand and are often the easiest rooms to serve. Existing single-panel radiators may be sufficient, especially in newer or well-insulated homes.
The Role of a Heat Loss Survey
A proper MCS heat loss survey tells you exactly which radiators need upgrading — and which do not.
Room-by-Room Calculation
We calculate the heat demand of every room in your home based on floor area, insulation, window area, and orientation. This gives us the radiator output needed for each room at heat pump temperatures.
Existing Radiator Check
We compare the output of your existing radiators at heat pump flow temperatures (using BS EN 442 data) against the room heat demand. Only rooms where there’s a shortfall need upgrading.
Targeted Upgrades
Many homes need only 1–3 radiator changes. Some need none. A heat loss survey prevents unnecessary spending and ensures your heat pump performs as expected.
Radiator Upgrades & BUS Grant
Radiator Costs Can Be Grant-Funded
The Boiler Upgrade Scheme grant covers the full heat pump installation, including necessary radiator upgrades as part of a system design. Oil and LPG homes can receive up to £9,000 to cover all costs.
Check your eligibilityGet a Free Heat Pump Quote — Radiators Included
Our quote includes a full heat loss survey, radiator assessment, system design, and grant check. No surprise costs at installation.