How to Model Electric Resistance Heating

Last Updated: 

Thursday, September 14, 2017

Software/Versions Affected:

• RESFEN›5
• RESFEN›6

RESFEN 5 does not model electric resistance heating. To get a rough estimate of the energy consumption for electric resistance heating, it is possible to model the building with a gas furnace/air conditioner, and then convert the gas consumption to electricity at an efficiency of 0.70 for existing construction and 0.78 for new construction.

To convert gas furnace heating results in MBtus to kWh, multiply the results in MBtu for heating by:

205.1 for existing construction

228.50 for new construction

Background:

Conversion for Btu to Watt-hours (W-h)

1 Btu = 0.293 W-h

1 MBtu = 1,000,000 Btu

= 293,000 W-h/MBtu

= 293 kWh/MBtu

Taking into account the furnace efficiencies of 0.70 for existing construction and 0.78 for new construction:

Existing Construction:

293 kWh/MBtu * 0.70

= 205.1 kWh/MBtu

New Construction:

293 kWh/MBtu * 0.78

= 228.50 kWh/MBtu

Example calculation:

If the Whole House Totals for Heating are as follows (for a gas furnace):

Heating = 55.12 MBtu

Calculate:

55.12 MBtu * 205 kWh/MBtu

= 11299.6 kWh