How to Size Unit Heaters

Unit heaters are a very basic and affordable way to provide heat to spaces that might not be heated otherwise. Garages, barns, shops, greenhouses, etc. are all examples spaces that can benefit from the versatility of a unit heater.

Figuring out how large of a unit heater you need is quite simple. (This is really the bare bones version of BTU equations. These numbers are good for estimating but are not exact.)

Formula:

Cubic Footage x Insulation Factor = BTU required

Cubic footage is simply Length x Width x Height.

The insulation factors are as follows:

4.0 - good insulation

5.0 - average insulation

7.0 - poor insulation

Generally it’s better to ere on the side of caution and oversize a unit heater for your particular space. Also, be sure to account for large windows or doors that don’t have matching insulation values.

EXAMPLE:

A pole barn with the following dimensions and insulation

Length 60’

Width 40’

Ceiling height 12’

Insulation – Average

The BTU to heat this building would be as follows:

60 x 40 x 12 x 5.0 = 144,000 (BTU required)

The best unit heater for this space would be a UH-140 (158,000 BTU).

Be sure to check out the new Hawken Energy Store to find the unit heater that’s right for you. Contact your local Factory Rep for distributor direct pricing!