An electric plenum heater can convert your existing natural gas, propane or oil furnace into a "dual fuel" heating system. An electric plenum heater gives you the ability to take advantage of the low-cost dual fuel electric rate and the flexibility to use the most cost-effective heating source at any time. The plenum heater is inserted into the plenum of your fossil fuel furnace, which is the duct work just above the furnace, and uses your existing furnace fan to move air across the plenum heater elements to heat your home. Both your fossil fuel furnace and the electric plenum heater utilize the same thermostat and ductwork. An electric plenum heater can be installed in conjunction with a central air conditioner. When installed with an air source heat pump it will deliver even greater savings.

Electric Resistance Heat vs. Fossil Fuels Cost Comparison

Type of Electric Heat

Efficiency

Cost/kWh

Propane/gal

Fuel Oil/gal

Natural Gas/therm

Electric Resistance Heat

100%

4.9-cents

$1.21

$1.41

$1.32

 
For an example, if you currently heat with propane, you would have to buy propane at $1.21 per gallon to equal the cost of heating with electric resistance heat at the dual fuel rate of 4.9-cents per kwh.