Best Radiators for Heat Pumps UK 2026

Why Heat Pumps Need Different Radiators

The physics first, because everything else follows from it.

A gas boiler sends water round your radiators at about 70 to 80C. A heat pump runs at 35 to 55C, and the lower end is where it's most efficient. That difference directly affects how much heat your radiators give out.

Radiators are rated at Delta T50: the heat output when the water is, on average, 50C hotter than the room. That's boiler territory. Drop the water temperature and the output falls faster than you'd think. On Stelrad's published correction factors, assuming a 20C room and water cooling by 5C across the radiator, the same radiator gives about 57% of its rating with the heat pump at 55C, and about 35% at 45C.

So Stelrad's 600x1200mm K2, rated 2,078W (7,092 BTU) at Delta T50, gives about 1,183W at 55C and 732W (2,500 BTU) at 45C. If the room needs more than that on a cold day, that radiator is too small for a heat pump.

This isn't a design flaw; it's physics. Heat pumps are efficient because they run at lower temperatures. The trade-off is bigger emitters: bigger radiators, better insulation, or ideally both.

Can You Keep Your Existing Radiators?

Possibly, and if you can, it saves a decent chunk of money. Your installer will do a room-by-room heat loss calculation as part of the design. You can get a rough idea yourself:

• Find the Delta T50 rating of your existing radiator (on a label, or in the maker's catalogue for that size and type). Multiply by 0.57 for a 55C system or 0.35 for 45C. That's roughly its output on a heat pump.
• Compare it with the room's heat loss on a cold day. The checker below works one out.
• If it still covers the room, keep it.

Rooms more likely to have a radiator that's already big enough: small bedrooms, hallways and cloakrooms, where builders fitted a standard size the room never needed. Rooms more likely to need upgrading: big living rooms, open-plan kitchen-diners, and any room with big windows or poor insulation.

Type 11 vs Type 21 vs Type 22: What Do the Numbers Mean?

Radiator type numbers look confusing but they're simple once you know the code. The first digit is the number of panels, the second the number of convector fins.

• Type 11: one panel, one set of fins. The thinnest, with the lowest output. Fine for small rooms with low heat demand.
• Type 21: two panels, one set of fins. On Stelrad's tables a 600x1200mm gives 1,616W, 37% more than the same-size Type 11. A middle ground where wall depth matters.
• Type 22: two panels, two sets of fins. Much more output than a single panel the same size, and what you want for heat pumps. Stelrad's 600x1200mm gives 2,078W against 1,176W for the same-size Type 11, 77% more.
• Type 33: three panels, three sets of fins. Very deep and heavy; only worth it for a big room with little wall width.

For heat pumps, Type 22 is the default. Only drop to Type 11 or 21 in small rooms with genuinely low heat demand, and even then err on the side of bigger. A slightly oversized radiator just lets the water run a degree or two cooler, which makes the heat pump more efficient.

Steel vs Aluminium vs Column Radiators

The material matters more than people think.

Steel panels

The cheapest and the best value for most rooms. They hold more water and take longer to warm up than aluminium, but that suits a heat pump: it runs for long periods at a steady temperature rather than blasting heat for an hour.

Aluminium

Warms up much faster, is lighter and looks more premium. Check the live price on the Reina Casina below against a steel panel of similar output. Worth considering for rooms you heat only now and then, a spare bedroom with smart TRVs for instance. In the main rooms, where the heat pump runs all day, the speed is largely wasted.

Column radiators

Beautiful in period homes, poor value for heat pumps: check the output per size against a Type 22, because you may need a physically bigger one to match. If looks genuinely matter more than budget in a particular room, buy a steel column and check its output table at your flow temperature.

Cast iron

Avoid for heat pumps unless you're prepared to oversize them enormously. Their outputs fall at heat pump temperatures by the same factors as any radiator (about 35% of the rating at 45C), so you'd need a very large one, and they're heavy.

The verdict: steel Type 22 panels for most rooms. Aluminium if you want premium or fast response. Column only where looks matter more than budget. Cast iron: don't.

Our Top Picks

The Stelrad Classic Compact is the everyday steel panel radiator, and Stelrad calls itself the "UK's No.1 Radiator Manufacturer". The range runs from 300mm to 700mm high and 300mm to 3,000mm long, every radiator is tested to BS EN 442, and Stelrad publishes the output for every size. Plumbers know them and merchants stock them, so a replacement later is easy to find.

The 600x1200mm K2 is 2,078W (7,092 BTU) at Delta T50; the 600x1600mm is 2,770W (9,455 BTU). At heat pump temperatures, take 57% of those at 55C or 35% at 45C.

They're not fancy: white powder coat, functional rather than beautiful. But they work, and they're everywhere, which is exactly what you want when you're changing several radiators across a house.

Where to buy it, honestly: a panel radiator is a builders' merchant product, not an Amazon one. Stelrad sells direct: on 23 October 2026 its site had the 600x1200mm K2 at £121.19 on offer (£184.73 normally), with a 10 year warranty. The Amazon button on the card is a search, because there isn't a dependable single listing. Get a merchant price before you order; merchants discount hard.

Henrad is the Stelrad's twin on paper: its Compact tables give the same outputs, size for size. A 600x600mm Type 22 is 1,039W / 3,546 BTU in both catalogues, a 600x1200mm is 2,078W in both, and the 600x1600mm differs by a single watt (2,771W against 2,770W). If anyone tells you one outperforms the other, they haven't read the tables.

So you're choosing on finish and price. Where to buy it: not Amazon. Henrad sells through merchants and publishes list prices on henrad.co.uk: £259.35 excluding VAT for the 600x1200mm Type 22, and nobody pays list. The Amazon button here is a search and will mostly turn up other brands.

If you want radiators that warm up fast and look genuinely good, aluminium is the way, and the Reina Casina is the one we link to. Aluminium radiators are light and quick to warm up, which suits rooms with smart TRVs doing zoned heating.

The catch is price: you pay considerably more than a steel panel for comparable output, which adds up fast across a house. For most people, one or two aluminium radiators in the main living spaces, with steel panels everywhere else, is the smart move. Check the output table for the size you're buying, at your flow temperature, before you order.

One practical note: fast-responding radiators on the same circuit as slow steel ones need the system balancing properly, so your installer should set the lockshield valves. Not a big deal, but worth flagging.

Columns, Verticals, Towel Rails and Budget Panels

Earlier versions of this guide picked a specific column radiator, vertical panel, budget Type 22 and towel rail. We couldn't find those models on their makers' sites any more, so here's how to choose rather than a model to buy.

• Column radiators (period homes): buy steel, not cast iron, and go tall where you can. Compare the column's Delta T50 output with a Type 22 of the same wall space, then apply the 57% or 35% above.
• Vertical panels (narrow walls in kitchens and hallways): Stelrad and Henrad both make vertical versions of their Compact panels. Expect to pay more than for a horizontal panel of the same output.
• Budget panels: any reputable Type 22 with a published BS EN 442 output does the job. Buy on the output table and the merchant's price, not the brand.
• Towel rails: a towel rail's Delta T50 output shrinks just like a radiator's, so a typical ladder rail gives only about 35% of its rating at 45C. In anything bigger than a small en-suite, plan on a small panel radiator to heat the room and a towel rail to dry the towels.

Side-by-Side

What a Full House Costs

On our estimates a radiator costs about £150 to £400 supplied and fitted: the lower end for a small one swapped onto the existing pipework, the top end for a large one or one in a new position. That's a sense-check against trade prices, not a quote, and it's the same figure our radiators for heat pumps guide uses.

Aluminium or column radiators in the main rooms push the top end up. Ask whether your heat pump installer will include radiator upgrades in the same heat pump quote, and compare that with a separate plumber.

One thing to be clear about: the Boiler Upgrade Scheme is not a radiator grant. It's a fixed £7,500 towards the heat pump, taken off the installer's total, so if the radiators are inside that quote the grant softens the whole job. Nobody hands you £7,500 for radiators on their own.

What You Don't Need

The radiator market is full of products that sound great in marketing copy but aren't worth the money on a heat pump.

Cast iron radiators. Beautiful, but designed for boiler temperatures. Unless you're prepared to oversize them enormously, avoid them.

Fan convectors everywhere. Myson pitches its fan convectors at low-temperature and heat pump systems, which makes them worth asking about for one hard-to-heat room. But they have a fan, so they make some noise, and if a big enough panel fits, the panel is the simpler answer.

"Heat pump" branded radiators at premium prices. Any Type 22 panel works at low temperatures; it just needs to be big enough. Compare the published output at your flow temperature, not the label on the box.

Underfloor heating everywhere. It spreads its heat across a huge surface, so it can run at the low flow temperatures a heat pump wants. But retrofitting it means taking up floors, insulating and screeding, which costs far more than radiators. It makes sense in new extensions, in ground-floor renovations where the floor is coming up anyway, and in new builds.

Room-by-Room Strategy

Here's how to approach each room. Think of it as the priority order for your budget.

Living room: upgrade first. Usually the biggest room with the highest heat demand. Fit the largest Type 22 that'll physically fit. If it's open-plan or has big windows, two radiators on separate walls can spread the heat better than one huge one. This is also where column or aluminium makes the most sense if you want to spend extra.

Kitchen/diner. Wall space is often limited by units. A vertical panel can fill a narrow gap; otherwise fit the widest Type 22 you can manage.

Bedrooms. Type 22 panels by default. Check whether the existing radiator is already big enough; in a small bedroom it may be.

Bathroom. Don't rely on a towel rail alone in anything bigger than a small en-suite: fit a small Type 22 panel to heat the room as well.

Hallway. Limited wall space; a vertical panel or a small Type 22 works. Hallways also benefit from fewer draughts, so if the front door is the main heat loss, fix that first.

And consider smart TRVs for per-room control. Drayton cites independent BEAMA testing that found TRVs and smart TRVs work with air source heat pumps and save 6 to 8%.

Installation Notes

Can you reuse the pipework? Usually, for like-for-like panel swaps in the same position. If you're upsizing a lot, your installer may want bigger pipes on some runs to keep the flow rate up. Let them assess it.

Clean the system. Old systems can collect magnetite sludge, which you don't want circulating through a new heat pump. Ask your installer to flush the system before the new radiators go on, and to fit a magnetic filter on the return pipe; ask whether both are in the heat pump quote.

DIY or professional? Swapping a panel onto existing valves is doable if you're handy: drain down, remove, hang the new one, reconnect, refill, bleed. If you're changing pipe sizes, moving radiators or fitting new valves, get a professional. Mistakes with heating systems mean leaks.

One final tip: ask your heat pump installer to quote for the radiators as part of the same job. The heat pump savings calculator can help you work out the overall costs.