Can Air Source Heat Pumps Heat Radiators?

An engineer installing a radiator in a home in the UK

Posted May 30, 2025

If you’re considering switching to low-carbon heating, you’ve likely asked: Can air source heat pumps heat radiators? It’s a valid concern, especially if you’re a UK homeowner, landlord, or commercial property manager looking to decarbonise heating without replacing your entire heating system.

Air source heat pumps (ASHPs) are growing in popularity across the UK as a sustainable and cost-effective alternative to gas boilers. Yet, many people hesitate because they assume radiators only work well with high-temperature systems.

The good news? Modern heat pumps can absolutely heat radiators effectively if your system is designed and configured properly.

In this expert guide, we’ll break down how air source heat pumps work with radiators, what upgrades may be necessary, and the benefits for homeowners, landlords, and commercial users.

Whether you’re researching your options or ready to install, this article will provide everything you need to make an informed decision.

How Do Air Source Heat Pumps Work with Radiators?

Air source heat pumps can work very effectively with radiators but the setup needs to be properly designed for low-temperature heating. Unlike gas boilers that typically send water through radiators at 70°C or more, heat pumps operate most efficiently between 35°C and 55°C.

This lower temperature means the heat output per radiator is reduced, so the system must be balanced correctly to keep your home warm and comfortable.

Matching radiators to an air source heat pump system

To make this work, your radiators need to release enough heat at these lower temperatures. That usually involves:

Using larger or more efficient radiators that can deliver the same warmth without high temperatures.
Checking your insulation levels. Well-insulated homes lose less heat, making lower-temperature systems more effective.
Carrying out a room-by-room heat loss calculation, which a qualified installer will do to ensure each space gets enough heat without wasting energy.

How big do radiators need to be for an air source heat pump?

Radiators may need to be 1.5 to 2.5 times larger than your existing ones, depending on the size of the room and how well your home is insulated.

For example:

A standard radiator that worked fine with your old boiler may not emit enough heat when paired with a heat pump.
Swapping it for a double panel version or a longer unit can help maintain comfort without turning up the thermostat.

To keep your rooms warm and comfortable, radiators must have a larger surface area to release the same amount of heat. Think of it like this: when the heat is lower, you simply need more of it to fill the space evenly.

Do you need to replace your radiators before installing an air source heat pump?

Not always. In fact, many UK homes already have “oversized” radiators, especially those built before energy efficiency was a priority. These are often more than adequate for use with a heat pump. A heat pump installer will assess:

The size, type, and location of each radiator.
Whether thermal upgrades (like loft or cavity wall insulation) reduce your heating demand.
If you need one or two key radiator upgrades, rather than a full replacement.

What are the signs that your current radiators are compatible?

Radiators stay warm for extended periods
Rooms heat adequately even when your boiler is set below 60°C
You already have double-panel or larger radiators

Pro Tip: Your installer should perform a whole-house heat demand calculation to size radiators accurately.

Do air source heat pumps take longer to heat radiators than gas boilers?

Yes, air source heat pumps typically take longer to heat radiators because they operate at lower temperatures. However, once the system reaches the set temperature, it maintains consistent comfort efficiently.

However, you can expect a different kind of warmth. Instead of short, intense bursts of heat like with a gas boiler, heat pumps deliver a steadier, gentler warmth throughout the day. It feels more consistent and often more comfortable especially when paired with smart thermostats and weather-compensated controls.

Expert Tip: If you’re retrofitting a heat pump into an existing home, consider pairing it with low-temperature radiator models or even underfloor heating in high-use areas. These options make the most of the heat pump’s efficiency without overhauling your entire heating system.

Thinking about switching to a heat pump but not sure if your radiators are up to the job?

At Future Heat, we provide MCS-certified installations across Tyne and Wear, Newcastle, and the wider North East. Our expert team will assess your home, insulation, and radiators to design a system that works efficiently with what you already have. Request your free, no-obligation air source heat pump quote today and find out how warm and energy-efficient your home could be.

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What Are the Benefits of Using Air Source Heat Pumps with Radiators?

Pairing air source heat pumps with radiators offers a balanced mix of cost-efficiency, environmental benefits, and improved property performance. Whether you’re a homeowner aiming to reduce energy bills, a landlord looking to boost EPC ratings, or a business chasing carbon targets, these systems provide long-term value without the need for disruptive renovations.

Homeowners: How can this upgrade save you money?

For UK homeowners, air source heat pumps can significantly cut energy bills and increase property value:

Lower running costs: When paired with well-insulated homes, ASHPs can cut heating costs by up to £500 per year (Energy Saving Trust).
Grants available: Access the Boiler Upgrade Scheme (BUS) offering up to £7,500 off the cost of installation.
Higher EPC ratings: Improves your Energy Performance Certificate, a key metric in home resale value.

Landlords: Why do air source heat pumps matter for rental properties?

Landlords are under pressure to future-proof properties ahead of evolving EPC regulations:

EPC compliance: From 2025, new tenancies may require minimum EPC C ratings.
Tenant retention: Tenants increasingly prefer energy-efficient homes with lower heating costs.
Long-term ROI: Energy upgrades like heat pumps can increase rental appeal and reduce void periods.

Tip: Combine ASHPs with smart thermostats and zone controls for added tenant comfort.

Commercial: What’s the ROI for businesses and large buildings?

Commercial property owners can benefit from:

Lower operating costs: Reduce reliance on gas and manage energy volatility.
Carbon footprint reduction: Helps meet Net Zero and ESG goals.
Government incentives: Claim capital allowances through schemes like the Enhanced Capital Allowance (ECA) or use the Smart Export Guarantee if paired with solar.

What Type of Radiators Work Best with Heat Pumps?

Not all radiators are created equal when it comes to compatibility with heat pumps. Since air source heat pumps produce lower water temperatures, radiators need to be efficient enough to heat rooms effectively. In many cases, existing radiators can remain in use, but some may need resizing or upgrading for optimal performance.

Should you switch to low-temperature or high-efficiency radiators?

For the best results with your heat pump, consider the following options:

Low-temperature radiators: Specifically designed to perform well at flow temperatures between 35°C and 45°C, providing consistent heat across the room.
Fan-assisted radiators (fan convectors): These radiators use small built-in fans to circulate warm air more effectively, allowing them to deliver higher heat output from a smaller unit size.
Aluminium radiators: These radiators are ideal for air source heat pump systems because aluminium is an excellent heat conductor. It heats up quickly and transfers warmth into the room faster than traditional materials like steel or cast iron.
This makes aluminium radiators highly efficient even at lower water temperatures, helping to improve responsiveness and reduce energy use.

What Installation Considerations Should You Be Aware Of?

Installing an air source heat pump is more than just a boiler swap, it requires a holistic approach that includes insulation, radiator sizing, and system design.

Proper preparation ensures the system operates efficiently and comfortably year-round, especially in colder months. An MCS-accredited installer is essential for quality assurance and grant eligibility to make sure your heat pump works in winter.

How to prepare your property for an ASHP?

Insulation first: Air source heat pumps work best in well-insulated homes.
Upgrade radiators if needed: Swap undersized radiators in key rooms.
Check EPC rating: Aim for at least EPC band D to qualify for some funding schemes.

Can I use existing pipework with an air source heat pump and radiators?

In many cases, yes. Existing pipework can be reused if it’s in good condition and suitably sized. Your installer will assess whether any sections need upgrading to support the system’s flow rate.

Who can install it?

Choose MCS-certified installers like Future Heat for quality assurance and to be eligible for grants like the Boiler Upgrade Scheme. Use the MCS Installer Search to find local experts.

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Cost, Funding and Payback Time: What Can You Expect?

While the upfront cost of installing an air source heat pump and upgrading radiators can be a concern, various government grants and long-term energy savings make it a financially sound investment.

Understanding your eligibility for schemes like the Boiler Upgrade Scheme can significantly reduce the burden and improve your return on investment.

What does it cost to upgrade radiators for a heat pump?

Per radiator: £150–£300 (depending on size and type)
Full system upgrade: £1,000–£2,000 for a typical UK home

What funding can help?

Boiler Upgrade Scheme: Up to £7,500 off the installation of an air source heat pump.
Green Home Finance Accelerator: Supports retrofit measures.
ECO4 Scheme: For eligible low-income households.

How long is the payback period for an air source heat pump?

The payback period for an air source heat pump depends on several factors, including your property size, insulation levels, current heating system, and eligibility for government funding.

In general, UK homeowners can expect a payback period of 6 to 10 years, thanks to lower running costs compared to gas or oil boilers, especially when paired with smart controls and efficient radiators.

Key factors that influence payback time:

Energy Bill Savings: Air source heat pumps can reduce annual heating bills by up to 40–60% when replacing electric, oil, or LPG systems.
Property Type and Usage: Larger, well-insulated homes with higher energy demands tend to see quicker returns, especially if switching from expensive fuel types.

Typical payback periods:

Standard UK Home (Replacing Gas Boiler): 8–10 years
Home Replacing Oil or Electric Heating: 6–8 years
Commercial Buildings or High-Use Sites: 3–5 years

Boosting your ROI:

To maximise your return on investment:

Upgrade to correctly sized radiators that work efficiently with the lower flow temperatures of heat pumps.
Improve insulation to reduce heat loss and lower your system’s workload.
Use smart thermostats and zoning to reduce energy waste.

Are There Alternatives to Radiators with Heat Pumps?

Yes, if radiators aren’t ideal for your property, several alternative heat distribution options are available.

Underfloor heating (UFH)

Excellent for new builds or major renovations. Underfloor heating is particularly popular in new builds, while hybrid systems allow a phased approach to replacing traditional gas heating. The choice depends on your property’s layout, budget, and long-term energy goals.

To better understand the benefits and setup, take a look at our guide on how air source heat pumps work with underfloor heating.

Hybrid systems

A hybrid heating system combines an air source heat pump with a traditional gas or oil boiler, allowing the two to work together based on efficiency and demand.

Typically, the heat pump handles the majority of the heating needs, especially for lower-temperature requirements like background heating and hot water.

The boiler kicks in only during peak demand periods, such as during extreme cold spells or for rapid heating.

This setup is ideal for properties that aren’t fully insulated or where a full heat pump retrofit isn’t yet practical. It also helps reduce upfront costs, since you can retain your existing boiler while gradually shifting to a low-carbon system.

Hybrid systems can be a stepping stone for households aiming to reduce emissions and fuel bills without committing to a complete system overhaul right away.

Heat pump-ready radiators

These are modern, high-efficiency radiators specifically designed to work with the lower flow temperatures (typically 35°C–55°C) of air source heat pumps.

They feature larger surface areas or improved heat transfer technology, which allows them to emit the same amount of heat as older radiators running at higher temperatures, without needing to be physically oversized.

They’re often slimmer, more stylish, and better suited for contemporary homes or low-carbon retrofit projects. Many models also offer quick response times and integrate well with smart heating controls, helping to improve comfort and energy efficiency.

Frequently Asked Questions (FAQs)

Yes, running a heat pump at a steady, low temperature is more efficient than frequently switching it on and off. This approach works well with radiators sized for lower flow temperatures.

Radiators won’t feel as hot to the touch because heat pumps use lower temperatures, but rooms can still reach the same comfortable ambient temperature if the system is designed properly.

In the UK, eligibility for a heat pump grant typically depends on the specific government scheme you’re applying under—such as the Boiler Upgrade Scheme (BUS) or ECO4. Homeowners and private landlords can usually apply if the property is in England or Wales, has a valid Energy Performance Certificate (EPC), and meets minimum insulation requirements. The home must also be replacing a fossil fuel heating system, such as oil, gas, or electric. Social housing and new builds are generally excluded unless under specific circumstances.

Yes, heat pumps are generally cheaper to run than electric radiators. This is because heat pumps are far more energy-efficient—they use a small amount of electricity to extract heat from the air or ground, providing more heat energy than they consume. In contrast, electric radiators convert electricity directly into heat, typically resulting in higher running costs. Over time, the lower running costs of a heat pump can lead to significant savings on energy bills.

BTechnically, yes.You can use electric radiators alongside a heat pump, but it’s not usually necessary or efficient. Heat pumps are designed to provide consistent heating throughout your home and are most effective when paired with low-temperature heat emitters like underfloor heating or larger radiators. Using electric radiators as a supplementary heating source may increase your energy bills and reduce the overall efficiency of your system. It’s best to optimise your heating system around the heat pump for maximum savings and comfort.

Our Verdict

Switching to a low-carbon heating solution doesn’t mean compromising on comfort or performance. Air source heat pumps can work effectively with radiators when properly configured, offering a future-ready alternative to traditional gas boilers.

For homeowners, landlords, and commercial property owners in the UK, this is an opportunity to reduce energy bills, improve EPC ratings, and contribute to sustainability targets.