How to Calculate your Heating and Cooling Requirement


To work out the heating requirement of an area there are several factors you need to consider. First you must determine what type of environment you need to heat.




Workforce Heating

Work out the volume of an area by multiplying the length x width x height in metres

The delta is the heat difference between the ambient temperature (air temperature) and the room temperature.
Ambient Temperature – Room Temperature = Delta

Determine the insulation level of the building requiring heating and attribute a specific number to each insulation level.

  • Well insulated            i = 1.2
  • Average insulation    i = 2.2
  • Poor insulation          i = 3.0
  • No insulation             i = 4.0

BTU duty required
With all this information you will be able to work out the BTU duty your area requires in this formula:
BTU duty required: Volume of area x Delta x Insulation x 4

KW duty required
There is 3412 BTU/hr in a kW, therefore you can work out your required kW duty through this formula:
kW duty required: Volume of area x Delta x Insulation x 4 ÷ 3412



To work out the cooling requirement of an area you require portable air conditioning for, there are also a few factors you must consider.

Find out your area’s volume through multiplying the length x width x height in feet

It is important to determine the number of people that occupy that area due to one person producing approximately 400BTU/hr of heat.

Any PCs or printers you have in a room will also give off heat, therefore it is important to note how many devices you have in a room. One PC/Printer will give approximately 400BTU/hr of heat.

BTU duty required
Use all this information to work out the BTU duty required for an area. To do this, you must use two
C1: Volume in feet x 5
C2: Number of people/PCs/Printers x 400BTU/hr
BTU duty: C1 + C2

kW duty required
kW duty: C1 + C2 ÷ 3412

Calculator functionality
If you do not have the time to work this information out or are having difficulties with the calculation, then have no fear as Cross Rental Services have a calculator which will be able to calculate your heating/cooling requirements automatically.


Heating Calculator