As the winter season approaches, homeowners may be considering their heating options and weighing the pros and cons of different systems. Two common heating options are propane furnaces and boilers, and air source heat pumps. In this article, we'll compare the efficiency and operating costs of these systems.

Propane Furnace or Boiler

Propane furnaces and boilers are popular heating options, particularly for homeowners in rural areas where natural gas lines may not be available. Propane is a clean-burning fuel that can be used for heating, cooking, and hot water. A.J. LeBlanc Heating installs and services propane furnaces and boilers for homeowners throughout our service area.

The efficiency of a propane furnace or boiler is measured by its COP (Coefficient of Performance). A COP of .96 means that for every unit of energy (in this case, a gallon of propane) that is burned, .96 units of heat are produced. The cost of propane varies depending on location and time of year, but on average, it costs around $3.75 per gallon in New Hampshire. Propane produces 91,333 BTUs per gallon.

Air Source Heat Pump

Air source heat pumps are another popular heating option for homeowners. Heat pumps work by extracting heat from the outside air and transferring it into the home. Because they move heat rather than generating it, heat pumps can be much more efficient than traditional heating systems. A.J. LeBlanc Heating installs and services air source heat pumps for homeowners throughout our service area.

The efficiency of an air source heat pump is also measured by its COP. A COP of 3 means that for every unit of electricity that is used to power the heat pump, 3 units of heat are produced. The cost of electricity varies depending on location and time of year, but on average, it costs around .30 cents per kilowatt-hour (kWh) in New Hampshire. Electricity produces 3,412 BTUs per kWh.

Cost Comparison

The cost of heating your home is determined by both the efficiency of your heating system and the cost of the fuel or electricity that powers it. Let's compare the cost per million BTUs of an propane furnace and an air source heat pump. To calculate the cost per million BTUs, we need to consider the cost of the fuel or electricity, as well as the COP of each heating system. For the propane furnace, we'll assume a fuel cost of $3.75 per gallon, and for the air source heat pump, we'll assume an electricity cost of $0.30 per kWh.

Propane Furnace Cost per Million BTUs

The heat output of a gallon of propane is approximately 91,333 BTUs. To produce 1 million BTUs of heat, a propane furnace would consume:

1,000,000 / 91,333 = 10.95 gallons of propane

At $3.75 per gallon, the cost of 10.95 gallons of propane is:

10.95 x $3.75 = $41.06

However, the propane furnace has a COP of 0.96, which means it only produces 0.96 units of heat for every unit of energy it consumes. To calculate the actual cost per million BTUs, we need to adjust for this:

$41.06 / 0.96 = $42.77

Therefore, the cost per million BTUs for a propane furnace is approximately $42.77

Air Source Heat Pump Cost per Million BTUs

The heat output of 1 kWh of electricity is approximately 3,412 BTUs. To produce 1 million BTUs of heat, an air source heat pump would consume:

1,000,000 / 3,412 = 293.1 kWh

At $0.30 per kWh, the cost of 293.1 kWh of electricity is:

293.1 x $0.30 = $87.93

However, the air source heat pump has a COP of 3.0, which means it produces 3 units of heat for every unit of energy it consumes. To calculate the actual cost per million BTUs, we need to adjust for this:

$87.93 / 3.0 = $29.31

Therefore, the cost per million BTUs for an air source heat pump is approximately $29.31.

Conclusion

Based on these calculations, the cost of producing 1 million BTUs of heat with an air source heat pump is significantly cheaper than the cost of producing 1 million BTUs of heat with a propane furnace or boiler. However, it's important to consider that the efficiency of an air source heat pump can vary depending on the temperature outside. In warmer temperatures, high efficiency heat pumps can have a COP greater than 4.0. In colder temperatures, the COP of an air source heat pump may be lower, which could increase operating costs, at 5 degrees the most efficient heat pumps have a COP of around 2.0. So, at 5 degrees it is more cost effective to run your propane furnace or boiler but at 17 degrees it makes more sense to run your heat pump.