BTU to kW metric conversion formula
BTUs to kWs Table Converter
| BTUs (British Thermal Units) | kWs (Kilowatts) |
| 3000 BTUs | 0.88 kWs |
| 5000 BTUs | 1.47 kWs |
| 6000 BTUs | 1.75 kWs |
| 7000 BTUs | 2.05 kWs |
| 8000 BTUs | 2.34 kWs |
| 9000 BTUs | 2.63 kWs |
| 10000 BTUs | 2.93 kWs |
| 11000 BTUs | 3.22 kWs |
| 12000 BTUs | 3.51 kWs |
| 13000 BTUs | 3.80 kWs |
| 14000 BTUs | 4.10 kWs |
| 15000 BTUs | 4.39 kWs |
| 16000 BTUs | 4.68 kWs |
| 17000 BTUs | 4.98 kWs |
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.
