How Radiators can heat low carbon homes
Many people think that heat pumps can only be used with underfloor heating because their temperature output is not as high as traditional gas boilers. It is believed that radiators are not big enough to deliver enough heat around the house. However, this is not true. You can use an air source heat pump to power radiators, and for many homes, the existing radiators are suitable.
Although gas boilers can output very high temperatures, they usually run no higher than 65°C. Any hotter and radiators pose a burn risk. Some heat pumps can reach the same high temperatures, but they tend to be relatively inefficient when outputting heat this high. Instead, they usually output temperatures of around 40°C to 45°C to ensure that they offer good efficiency and adequate heating for the home.
Most radiators found in UK homes are oversized for a gas boiler system running at 60°C to 65°C. This is because it is safer to install bigger radiators than to risk having smaller radiators which may not keep a home warm. As a result, even if an air source heat pump outputs just 40°C, the oversized radiators in most homes are actually the right size required for an air source heat pump.
Aluminium radiators are an excellent choice to use with heat pumps. Aluminium is a highly effective conductor, and aluminium radiators heat up very quickly and transmit their heat into the room much more rapidly than steel or cast iron radiators. As the heat pump's water temperature is lower compared to a gas boiler, it is necessary to conduct as much of this heat as possible quickly through the home. Aluminium is the perfect material for this job.
