Which Radiators Give Out the Most Heat?

The amount of heat given off by any radiator is largely determined by its surface area, the time it takes to warm up and cool down affects the way in which we use each type of radiator.

Radiators are usually made from 3 material types; Aluminium, Steel and cast iron.

Aluminium has the property of being able to heat up and cool down quickly making it easy to control and requires a lower water content to operate making it more cost-effective. However, it has some restrictions on the designs that can be made with it.

Steel radiators are the most popular in the UK and have been used for many years, standard panel rads often have additional fins to create more surface area whilst designer models use one two or even three sets of tubes to achieve a similar result. This allows us to get more heat from the same size radiator as one with just one set of tubes or no fins.

Cast Iron radiators hold heat for a long time giving even and steady heat distribution, but they take longer to heat up in the first place and require larger volumes of water to be heated to fill the system.

Usually vertical or horizontal formats do not influence the amount of heat released, they simply make the best use of your space. Any radiator you buy should have an output listed and tested to a standard called EN442 in an approved laboratory, this means you can rely on the radiator to deliver the heat you need. Outputs are tested with set water temperatures that replicate a typical heating system, so you can compare each option equally, this formula gives what we call the Delta T number, the UK standard Delta T for heating systems is T50.

Today some systems use lower temperature flow (from heat pumps for example) this creates different delta T results and you can do a conversion calculation to find out how much heat is delivered by the same radiator using these lower temperatures.