Do Your Radiators Need Upgrading for a Heat Pump?

Do my radiators need upgrading for a heat pump?

Many homes now have the chance to heat using alternative methods, especially after the government announced a heat pump grant to assist those considering the transition to carbon-neutral heating. However, many do not realise that heat pump installation can bring other costs, such as upgrading your radiators. This guide explains whether it is necessary to upgrade your radiators when getting a heat pump installed, and when to ask a heating engineer for a professional assessment.

Why radiator performance matters with heat pumps

Radiator output is usually listed assuming the radiators run at around 70°C, which is typical of a conventional boiler. Heat pumps have a minor drawback in that they only operate at certain flow temperatures and are more effective at lower temperatures. The ideal operating temperature for heat pump-powered radiators is around 50°C — and the lower the temperature, the better — so radiators need to deliver the same heat output at these reduced temperatures to keep rooms comfortable.

How radiator size affects output

For heat pumps, particularly in older homes, radiator size is a crucial factor. It not only guarantees that your heat pump operates, but it also makes the single largest contribution to how well it operates. Older radiators with a single panel or without convector fins usually deliver less heat at reduced temperatures and may struggle to meet a room's heat loss when paired with a heat pump.

Working out the radiator size you need

The process to determine this is quite complicated. First, you must complete a thorough room-by-room heat loss analysis, and then use something called conversion factors to determine the size of radiator you are looking for. If a radiator cannot deliver the watts a room requires at, say, 50°C, it will need to be replaced or supplemented.

Checking radiator power: the practical steps

As usual, when it is chilly outside, we must work out how much energy we use in each particular room. To do this, you can use a Heat Loss Calculation Sheet. This is not a substitute for full calculations but gets us close. After determining the number of watts or kW needed in a space, you must work out whether your radiator can generate that number of watts at the new, lower temperature of around 50°C.

There are many types of radiators available, and from the top of your radiator you can see how many panels and convector fins you have — the first number indicates the number of panels. If your radiators do not have convector fins, you should probably update them anyway because of their age, let alone the reduced output they have.

Other factors you need to consider

The above assumes you will not cover your radiators in any way and that they have enough free circulation, such as without a shelf above them. It is also worth noting that while high-temperature heat pumps are available, we always recommend low temperatures since they have significantly lower running costs and provide more comfort.

Speak to a heating engineer

The best way to find out whether you need to upgrade your existing radiators when getting a heat pump installed is by speaking to highly knowledgeable and experienced Gas Safe registered engineers. Our heating engineers across Pulborough, Billingshurst and Storrington specialise in installing heat pumps. If you would like their professional advice, simply get in touch by calling us on 01903 740538 or 07871 725133 and we will be happy to help.

To learn more about our specialist installations, see our air source heat pumps page, or contact us to arrange a home visit.