When considering whether to move to a heat pump system, you may wonder how heat pumps work, whether radiators are a suitable option to distribute that heat around your home, or if you can use your existing radiators.

The simple answer is that radiators can be paired with a heat pump system; in some cases, you can use your existing radiators with a heat pump. However, they would need to be adequately sized to operate at a lower flow temperature than they usually would with a gas boiler.

If your radiators are  small, they can be easily replaced with bigger radiators that function at the correct flow temperature for a heat pump. An alternative might be to consider underfloor heating when installing an air- or ground-source heat pump system, though we appreciate this may not always be practicable. 

If you want to reduce your energy bills, consider a government-backed free air source heat pump grant ECO4 scheme, which aims to help low-income households in the UK. Air source heat pumps can save money and provide an efficient and cost-effective way to heat your home compared to traditional heating systems. This article outlines all you need to know about air source heat pumps and combining them with radiators, whether newly fitted or existing radiators.

What Is An Air Source Heat Pump? 

An air-source heat pump requires electricity to power it. It absorbs heat from the air around a building and then converts that cold air into warm air that can be used to warm a home or other space. This is meant to be a better way to heat your home for the environment than a regular gas heater. The pump is generally put next to a wall on the outside. It looks like an air conditioner. It is buried in the ground and has lines that carry hot water connected to it. 

How Does An Air Source Heat Pump Work?

The air entering the pump is pushed over tubes filled with refrigerant, raising the fluid's temperature and turning it into a gas. The gas is then pushed through a compressor, which raises the pressure and heat. A heat exchanger with cool air or water around it moves this hot gas. The refrigerant then heats the air or water around it before circulating it through the house to heat pipes, heat the floors, and provide hot water. 

Air source heat pumps are installed outside your house. It's best to place them somewhere that gets full sunlight so the pump doesn't have to work too hard to heat the air around them. This advice isn't necessary, though, because the pumps are made to heat air even when it's below freezing outside. So, you can be sure that a heat pump will work no matter where it is placed or how cold it is outside. 

Heat Pumps With Radiators

Heat pumps work better when cooler than gas boiler-fed radiators, which work best when the flow temperature is higher. Because the flow temperatures are lower (usually between 40°C and 50°C compared to 65°C to 70°C with a gas boiler), the heat emitting surface for a heat pump system needs to be bigger than for a boiler heating distribution system. This is why underfloor heating should be considered when installing a heat pump system.

But underfloor heating isn't always possible, especially on upper floors or with raised flooring. In these cases, radiators are a good option. Radiators can be used with air and ground-source heat pumps to heat the whole house; in some cases, the radiators you already have may work. However, they will need to be the right size for them to work well.

Can Heat Pumps Use My Existing Radiators?

Your radiators should work with a heat pump as long as they are big enough to be set to a lower base temperature. Even though radiators work at higher temperatures, this method works because switches in central heating systems often turn them on and off. You won't feel a change in the heat in your home because a heat pump that works at a lower temperature can keep going to provide the same amount of heat as a gas-powered heater. 

There are times when the heaters in your home are already big enough to heat the same amount of space as a heat pump. They work well with various radiators, such as steel panels and cast iron radiators.

A plumber or heating tech can measure the heat from your radiators to find the best setting for the new heat pump to work at the same rate. This will tell you if your old radiators are suitable for the new heat pump system.

A heating engineer must ensure the system is well-cleaned when using existing radiators before installing a heat pump. This prevents particles from getting stuck in the pump's filter. 

Summary

However, it's now clear that radiators can often be combined with an air-source heat pump system to heat your home. In some instances, you may be able to connect your existing radiators with a new heat pump system.

While underfloor heating, where practicable, would be considered a better option due to its larger heat-emitting surface, radiators (of the right size for the system) will nonetheless perform suitably well. This can be easily done if you need to replace your existing radiators as part of an overhaul of your heating system.