The terms ΔT50 (Delta T50) and ΔT30 (Delta T30) describe the temperature difference between the radiator’s average surface temperature and the room temperature. For example, a ΔT50 radiator will operate at a higher temperature than a ΔT30 radiator. A lower water temperature means you will need a larger radiator to emit the same amount of heat.
Most radiators manufacturers & suppliers will quote ΔT50 heat output of their radiators as this has historically been the most common type of heating system. As more and more households move to heat pumps, ΔT30 radiators will become more common.
