Dual fuel is the combination of a fossil fuel furnace, normally gas or oil, with a heat pump. The idea being that during the milder weather the heat pump will transport heat into your home from the outside air cheaper than burning gas or oil. (get a more detailed explanation of how a heat pump works). When it gets very cold, around 35 degrees, also known as the balance point, the heat pump automatically shuts down and the furnace heats the home. This is a great system for certain applications.
The heating system in your home converts fuel into heat. Any type of heat can be measured by using a term called a "BTU" or British Thermal Unit. A BTU is a small unit of heat, comparable to the amount of heat you get from one wooden match. An average Midwest home may use 60 to 80 million BTUs each winter.
To compare different heating fuels and heating systems we need a common unit of measure that applies to all fuels. The "Cost per one Million BTUs" (Cost per MBTUs) is the best way to compare the heating costs associated with different fuels and different heating systems. Each fuel and heating system will have its own Cost per MBTUs based on the efficiency of the system and the price of the fuel.
|Here are some example fuel prices to compare different heating systems:|
|Natural gas||60% efficient||$1.20/CCF(therm)||Cost per MBTUs = $20.00|
|Natural gas||80% efficient||$1.20/CCF(therm)||Cost per MBTUs = $15.00|
|Natural gas||90% efficient||$1.20/CCF(therm)||Cost per MBTUs = $13.33|
|Electric||Furnace||$.06/kWh||Cost per MBTUs = $17.58|
|Electric||12 Seer heat pump||$.06/kWh||Cost per MBTUs = $8.00|
|Propane gas||80% efficient||$1.60/gal.||Cost per MBTUs = $16.67|
As shown in the list above, if you know the type of heating system and the current cost of fuels, you can easily compare different fuels and heating systems. View a quick comparison of most common heating systems. In this file you can find current rates, the cost per Million BTUs, the amount of heat needed for an average size home and the winter heating cost for all the systems listed.