Heat pump making your lounge feel like the frozen aisle? Your radiators might be the real culprits.
- [1] How Heat Pumps and Radaitors Work Together
- [2] Do You Need Special Radiators for a Heat Pump?
- [3] Best Radiator Types for Heat Pumps
- [4] Sizing Your Radiators for a Heat Pump
- [5] Cost of Upgrading Radiators for a Heat Pump
- [6] Efficiency and Comfort Benefits
- [7] When You Can Keep Your Existing Radiators
Heat pumps are cracking bits of tech - great for slashing carbon emissions and trimming those pesky energy bills - but they’re only as good as the rads they’re working with.
Unlike gas boilers, which churn out water hot enough to brew a cuppa, heat pumps run at lower temperatures.
That means your radiators need to be the right size and style to keep your home properly toasty.
In this guide, we’ll walk you through everything you need to know about heat pump radiators in 2025: the best types, how to size them, what they cost, and when it’s worth an upgrade.
Let’s dive in…
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🔑 Key Takeaways:
Best Radiators for Heat Pumps - Double-panel convector radiators, low-temperature radiators, and fan-assisted models are top choices for maximising heat pump efficiency. Aluminium radiators heat up faster than steel or cast iron.
Size and Surface Area Matter - Heat pumps operate at lower flow temperatures (35-55°C vs. 60-75°C for gas boilers), so radiators need larger surface areas to deliver enough heat.
Average Upgrade Costs - Expect £200-£400 per radiator replacement, with whole-house upgrades ranging from £500-£1,500 depending on the number of radiators.
Efficiency Gains - Properly sized radiators can boost your heat pump’s Seasonal Coefficient of Performance (SCOP) by up to 20%, potentially saving £234 annually on energy bills for a typical gas household with a smart tariff.
[1] How Heat Pumps and Radaitors Work Together
Heat pumps - whether air source or ground source - usually heat water to around 35–55°C.
That’s a fair bit cooler than the 60–75°C you’ll get from a gas boiler. The lower the flow temperature, the harder your radiators need to work to keep rooms cosy.
The fix? Go bigger.
Radiators with more surface area (or ones built for low-temperature systems) can throw out more heat at these gentler temps, helping your home stay snug without the heat pump working overtime.
It’s a bit like brewing tea - a tiny teaspoon will do the job eventually, but a bigger one gets the sugar mixed in faster. For heat pumps, surface area is the secret ingredient.
[2] Do You Need Special Radiators for a Heat Pump?
Not necessarily.
You don’t always need fancy “heat pump radiators” - standard ones can work just fine if they’re sized properly for lower flow temperatures.
The old chestnut that heat pumps only work with underfloor heating? Rubbish. Radiators are perfectly capable, as long as they’ve got enough oomph.
“Oversizing” sounds extreme, but all it really means is giving your radiators enough surface area to make up for the cooler water.
If yours are too small, you’ll end up cold, your heat pump will be grafting harder than it should, and your bills will thank you by going up.
A good heating engineer can run a heat loss calculation to see exactly what you need - no guesswork, no sales fluff.
[3] Best Radiator Types for Heat Pumps
Not all radiators are created equal when it comes to heat pumps.
Here’s the lowdown on the best options:
Double Panel Convector Radiators - these have a larger surface area and fins to boost heat output, making them ideal for heat pumps. They’re efficient and widely available.
Low-Temperature Radiators - designed specifically for heat pumps, these operate efficiently at 35-45°C, like Jaga’s Low-H₂O models, which can be up to 16% more economical than standard steel radiators.
Fan-Assisted Radiators - these use small fans to push heat into the room, perfect for smaller spaces or retrofits where oversized radiators won’t fit. They’re pricier but effective.
Underfloor Heating as an Alternative - Underfloor heating is the gold standard for heat pumps due to its massive heat-emitting surface, but it’s pricier (£2,000-£11,000) and more disruptive to install, especially in existing homes.
Aluminium radiators are also a great shout - they heat up faster and transfer heat more efficiently than steel or cast iron. Avoid decorative column radiators or towel rails, as their small surface areas are less efficient with heat pumps.
[4] Sizing Your Radiators for a Heat Pump
Radiator sizing isn’t a guessing game - it starts with a proper heat loss calculation.
A qualified heating engineer (ideally MCS-accredited) will work out exactly how much heat each room needs.
They’ll factor in insulation, room size, window area, and even where you live in the UK - because keeping a home warm in Aberdeen is a very different job to one in Brighton.
To give you an idea:
A typical living room (4m x 5m) in a moderately insulated home might need a radiator output of 2,000–2,500 watts at a Delta T of 30 - the standard for heat pump flow temperatures.
A smaller bedroom (3m x 3m) could be fine with 1,000–1,500 watts.
Get the sizing right and your heat pump won’t have to break a sweat to keep things cosy.
Here’s a rough guide:
Room Type | Size (m) | Heat Output (Watts ΔT30) |
Living Room | 4m x 5m | 2,000-2,500 |
Bedroom | 3m x 3m | 1,000-1,500 |
Bathroom | 2m x 3m | 800-1,200 |
Always get a professional to confirm exact sizing, as poor calculations can lead to chilly rooms or sky-high bills.
[5] Cost of Upgrading Radiators for a Heat Pump
Upgrading radiators isn’t pocket change, but it’s usually a one-off job that boosts efficiency for years to come.
For standard double-panel convectors, expect £200–£400 each. Low-temperature or fan-assisted models can run £300–£500 a pop.
In a typical three-bedroom home with 5–8 radiators, a full swap could cost £1,000–£3,000 - still far cheaper than underfloor heating (£2,000–£11,000) and much better than living with undersized rads that drive up running costs.
If you’re installing a heat pump under the Boiler Upgrade Scheme, you can bag £7,500 towards the system - and if radiator upgrades are part of the install, that’s a chunk of the cost covered.
[6] Efficiency and Comfort Benefits
Match your heat pump with the right radiators and you’ll feel the difference - both in your home and your energy bills.
Properly sized rads can boost your heat pump’s SCOP (Seasonal Coefficient of Performance) by up to 20%, meaning it uses less electricity to give you the same cosy heat.
For a typical gas household switching to a heat pump on a smart electricity tariff, that could mean saving around £234 a year.
Comfort gets a glow-up, too. You’ll get steadier temperatures, without the on-off blasts you get from a gas boiler. And if you go for low-temperature radiators or underfloor heating, the heat spreads more evenly, so those cold corners finally get the memo.
[7] When You Can Keep Your Existing Radiators
Good news - you might not need to rip out your rads at all. If your home is less than 20 years old, or you’ve had a modern central heating system fitted recently, there’s a decent chance your radiators are already “oversized” for a gas boiler.
That means they could handle a heat pump’s lower flow temperatures without breaking a sweat.
Well-insulated homes (think double glazing, cavity wall insulation, and a snug loft) are also more forgiving, as they hold onto heat for longer.
A heating engineer can give you a definitive answer with a heat loss survey. But if your rads are pushing 30 years old or are weedy single-panel models, an upgrade’s usually the smarter move for comfort and efficiency.
Next Steps For Your Heat Pump Journey:
When planning to install a heat pump for your home, there are several important factors to consider. Make sure to refer to the following guides to help you make informed decisions:
To dive deeper into these topics, head over to our advice section or check out our YouTube channel to learn more.
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