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## BTUs to kWs Table Converter

To calculate BTU’s transferred to the other side of the roof you need to know also Thermal resistance of the roof assembly (R).

• 3412.142 BTU hours = 1 kW hour
• 1000 BTUs = 0.293 kW
• 1 kW = 1000 watts

The formula looks like this:

(T1 – T2)/ R or if R = (R1+R2+R3+R4…Rn) formula looks like this: (T1- T2)/ (R1+R2+R3+R4…Rn);

Formula is in the American (Imperial) units so all data we need to transform to American units:

• 40C=104F; current roof temperature
• 30C=86F; reduced roof temperature with Super Therm
• 25C=77F; ambient air temperature
• 3,000m2=32,290ft2; area of the envelope of building
• R=11.18BTU/hr ft2 F; R-value for the roof could be any (assuming insulation installed)

So, here are the results for a heat transferred with the data entered:

(104F-86F)/11.18BTU/hr ft2 F = 1.61BTU/hr ft2;

For 32,292ft2 roof: 1.61BTU/hr ft2 F * 32,292ft2 = 51,990.12 BTU/hr;

51,990BTU/hr = 15.24 kW;

kW per m2 is 15.24 kW/3000m2=0.0051kW/m2.

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