Design Rules of Thumb

The design rules below are intended for informational purposes only. They are based on new home construction using the latest technologies and standards. One should have a heat loss calculation done by a professional to insure a proper system is designed.

North Itasca Electric is able to help you in these calculations. If you desire assistance, call 1-800-762-4048 or 218-743-3131 Monday thru Friday 8:00 AM to 4:30 PM (Winter hours) or Monday thru Friday 7:00 AM to 3:30 PM (Summer hours).

Electric boilers:

If you are looking for just a little additional warmth, figure 6 watts per square foot.
If you are looking for 100% space heating on our Dual Fuel program figure 9 to 10 watts per square foot.
If you are looking for 100% space heating with Storage program figure 15 to 17 watts per square foot.

Plenum Heaters:

Plenum heaters can be sized using 8 to 10 watts per square foot with 8 foot ceilings.

Use 15 kW models in structures 1500-2000 square feet.
Use 20 kW models in structures 2000-2500 square feet.

A minimum air flow of 1000 CFM's is needed for 15 kW plenum heaters with proper ductwork installed and about 10 registers.

A minimum air flow of 1200 CFM's is needed for 20 kW plenum heaters with proper ductwork installed and about 12 registers.

Steffes Furnace:

The sizing of brick storage units receiving 8 hours of charge each day:

Square foot Method:

Basements:
Square feet x 8' ceiling x 1.75 = Btu's
First floor:
Square feet x 8' ceiling x 2.75 = Btu's

Cubic foot method:

2.75 Btu's heat loss per cubic foot for the upper level and 1.75 Btu's heat loss per cubic foot for the basement.
Home on slab or crawl space:
3.1 Btu heat loss per cubic foot for all areas.

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