COST TO RUN ELECTRIC FURNACE V.S. NATURAL GAS FURNACE

[moonbeambill]

Please help me compute cost to run a 110,000 BTU furnace for one minute so that I can compar this to running a 15,000 watt electric heater. The marginal cost for natural gas is $ 1.79/Therm and the marginal cost for the electricty is $ 0.17806. THANKS FOR YOUR HELP MOON :P

[Guest]

Please help me compute cost to run a 110,000 BTU furnace for one minute so that I can compar this to running a 15,000 watt electric heater. The marginal cost for natural gas is $ 1.79/Therm and the marginal cost for the electricty is $ 0.17806. THANKS FOR YOUR HELP MOON :P

You really need to look at equal amounts of heat, as both presumably have thermostats and cycle on and off to maintain set temperature.

A therm is 100,000 BTU, so your furnace consumes 1.1 therm/hour, and costs $1.97 per hour running continuously (remember it actually cycles).

1 BTU/hr = 0.293071 W, so 110,000 BTU/hr = 32.2378 kW (your electric heater produces less than half the heat, and would run more than twice as much). The cost of consuming 32.2 kW-h is $5.74, not the way to go.

Probably better to look at both as a cost per megajoule.
1 therm = 105.506 MJ, so gas is $1.79/therm x 1 therm/105,506 MJ = $0.016966/MJ

1 kWh = 3.6 MJ, so electricity $0.17806/kWh x 1 kWh/3.6 MJ = $0.04946/MJ.

It would never offset the difference but some of the gas heat goes up the chimney, and the efficiency of the furnace needs to be considered. The electric heat is all delivered to the premises.