The following data is from the EERE site: http://www.eere.energy.gov/consumerinfo/factsheets/cb5.html
Bear in mind that this is the efficiency of the furnace itself. It does not include any heat losses from the duct system that may pass through your attic, crawl space or other unheated area. These losses can be surprisingly high as detailed here: http://oikos.com/esb/28/duct_losses.html
Fuel Type - Heating Equipment | Efficiency (%) |
---|---|
Coal (bituminous) | |
Central heating, hand-fired | 45.0 |
Central heating, stoker-fired | 60.0 |
Water heating, pot stove (50 gal.) | 14.5 |
Oil | |
High efficiency central heating | 89.0 |
Typical central heating | 80.0 |
Water heater (50 gal.) | 59.5 |
Gas | |
High efficiency central furnace | 97.0 |
Typical central boiler | 85.0 |
Minimum efficiency central furnace | 78.0 |
Room heater, unvented | 99.0 |
Room heater, vented | 65.0 |
Water heater (50 gal.) | 62.0 |
Electricity | |
Baseboard, resistance | 99.0 |
Central heating, forced air | 97.0 |
Central heating, heat pump | 200+ |
Ground source heat pump | 300+ |
Water heaters (50 gal.) | 97.0 |
Wood & Pellets | |
Franklin stoves | 30.0 - 40.0 |
Stoves with circulating fans | 40.0 - 70.0 |
Catalytic stoves | 65.0 - 75.0 |
Pellet stoves | 85.0 - 90.0 |