British Thermal Unit per hour is the standard measurement used to state the amount of output of any heat generating device.

Type 11

Also known as Type K1, is a type of radiator with 1 radiator panel and 1 set of convection fins.

Type 22

Also known as Type K2, is a type of radiator with 2 radiator panels and 2 sets of convection fins.


ΔT50 is the UK standard, however Henrad also quote at lower levels for lower water temperature systems.


The warranty covers any defect that is attributable to a manufacturing, assembly or material fault, further details available on request.


Refers to which position the pipes are connected to the radiator, OE means opposite end i.e. 1 pipe on each side, TB is top bottom i.e. 1 pipe is connected to the top and 1 to the bottom, B is both pipes connected to the bottom.


A European wide colour matching system.

The CE marking is the manufacturers declaration that the product meets the requirements of the applicable EC directive. This is applicable to all Henrad products.


Is another measurement for heat output, 1 watt is equivalent to 3.412 Btu/hr.

Type 21

Also known as Type P+, is a type of radiator with 2 radiator panels and 1 set of convection fins.


Refers to the difference in temperature between the water circulating in the central heating system and that of the ambient temperature. It is important to use the correct Δt when selecting your radiators, as the same radiator will have different outputs at different water temperatures.

Heat loss

Is the amount of heat a room loses, it is therefore an important calculation when determining what size radiator is required to heat a room to the correct level.

Is a set of International regulations related to quality management systems.

EN 442 is the European standard which defines the manufacturing standards for radiators and convectors which operate at temperatures of less than 120°C. The standard defines the type of steel which must be used, the type of pressure testing which must be carried out and the accuracy of the heat outputs quoted in the literature.


British Standard Piping.