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BTU Calculator

1How many cubic feet do you want to heat?
multiplication multiplication equality
width length height number of ft3
2What is the temperature difference needed between the outside temperature and the desired inside temperature?
substraction equality
outside temperature temperature wanted inside difference in degrees
3Establish the DIFFERENCE factor
Establish the BTU factor using the temperature difference in step 2:
Difference of between the outside temperature and the temperature wanted inside Factor
4What is the insulation or "R" factor?
Well insulated = Factor 2
Enclosed area with windows and walls installed.
Partly insulated = Factor 4
Walls installed, no insulation.
Doors and windows covered with tarps.
Poorly insulated = Factor 7
Most walls installed.
Not insulated = Factor 8,5
Main walls not installed, area enclosed by tarps.
5Calculate the required BTUS:
multiplication multiplication equality
number of ft3 Difference factor "R" factor Number of BTUs needed

Propane consuption guide

 Here is a simple way of calculating your fuel needs when using a propane heater:

The basic rule:
At -17°C one 100 lb tank provides 64,000 BTU
At -7°C one 100 lb tank provides 94,000 BTU

Just divide your BTU needs by 64,000 or 94,000.

Example: A 300,000 BTU heater, temperature where the cylinders are located is -17°C
300,000 BTU/64,000 BTU = 4,69 cylinders

Since the law prohibits connecting more than 4 tanks of propane to a single piece of equipment, using 100 lbs tanks is not recommended to get maximum output.