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Delta T 50° and Delta T 60° - What's the Difference?

 

Delta T, also written ΔT, represents the difference between two temperatures - e.g. between a radiator and a room.

 

For example, if a room is at 15°C and the radiator is at 65°C the ΔT is (65°-15°) = 50°C.

The vast majority of radiator sellers show radiator output in terms of ΔT 50°. This is because ΔT 50° is the current European testing standard for modern boilers such as condensation boilers which have lower flow and return temperatures than older boiler systems  which use ΔT 60°. So, in order to avoid radiators being incorrectly sized, it is important to know the heating system's temperatures and take them into consideration. It is also extremely important when calculating your rooms' requirements to know what basis you are using - for example, if your calculation is based on ΔT 50° and you choose radiators whose output is based on ΔT 60°, then the output of your radiators will be too low.

 So, when comparing radiator outputs and prices be sure to check which ΔT is being quoted. You can use the following table to compare radiator outputs:

 
 
 
 
 
 
 
 
 
 
 
 
ΔT at 60°C
Correction Factor
 
ΔT at 50°C
Conversion Factor
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
60°
1.000
 
60°
1.280
 
 
 
 
 
55°
0.901
 
55°
1.154
 
 
 
 
 
50°
0.781
 
50°
1.000
 
 
 
 
 
45°
0.699
 
45°
0.895
 
 
 
 
 
40°
0.599
 
40°
0.767
 
 
 
 
 
35°
0.513
 
35°
0.657
 
 
 
 
 
30°
0.424
 
30°
0.543
 
 
 
 
 
25°
0.338
 
25°
0.433
 
 
 
 
 
20°
0.256
 
20°
0.328
 
 
 
 
 
15°
0.179
 
15°
0.229
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Example:  Let's assume we have a radiator that gives 2000 Watts at ΔT (delta T) = 60°.
 
At ΔT (delta T) = 40°, the output would be 2000 x 0.599 (from the table above) = 1198 Watts,
 
At ΔT (delta T) = 20°, the output would be just (2000 x 0.256) = 512 Watts. 
           
                   
   

 

© Budget Radiators (UK) Ltd