## Different Companies Sometimes State Different Heat Outputs for the Same Radiators, Why?

Calculating your heat output requirement from a radiator and finding the appropriate size of radiator can be confusing.

For example:

However, your plumber tells you that the same radiator, X radiator in white, 600mm high x 1000mm wide but from his supplier, ACME Radiators, only gives out 1000 Watts. How can this be?

To explain, heat outputs can be measured in 2 different ways; the way they are measured is done against the “delta T” or “Δt” of the system.

In the UK, the standard for calculating heat outputs is illustrated by the following example:

• Flow water temperature (on entering the radiator)  keluaran hk  – assumed to be at 90ËC
• Return water temperature (on exiting the radiator) – assumed to be at 70ËC
• This means the average water temperature running through the system is assumed to be 80 ËC
• From this figure, you minus the average room temperature – assumed to be 20 ËC
• This equates to the Δt60 ËC standard.

In Europe, the standard for calculating heat outputs is illustrated by the following example:

• Flow water temperature (on entering the radiator) – assumed to be at 75ËC
• Return water temperature (on exiting the radiator) – assumed to be at 65ËC
• This means the average water temperature running through the system is assumed to be 70 ËC
• From this figure, you minus the average room temperature – assumed to be 20 ËC
• This equates to the Δt50 ËC standard.

To be clear, there is no difference in the radiator, it is just a different way of recording the performance. Like metric versus imperial; the numbers may be different, but they mean the same thing.