A heat pump transfers heat to a warmer area from an area with cool air. It absorbs the heat that occurs naturally outside and moves it inside. It runs on electricity and can work with existing ductwork or work as a ductless system.
A natural gas furnace supplies heat by heating up natural gas in its burner, the resulting flame then heats up the metal heat exchanger and exhaust out of the flue, the heat is transferred by the heat exchanger into the incoming air, finally the furnace blower forces the heated air into the ductwork and throughout the home. Once the air fills the room, the colder air is drawn into the furnace via the return ducts and the process starts all over.
The rivalry between these two forms of heating has been going on for a while with home owners wondering which is better and cheaper, and there is no definitive answer to this question as there are several factors to consider:
Efficiency: natural gas boilers are considered to be between 50% to 75% efficient, that means only about half of the energy supplied to it is converted into heat, what is left is wasted, but newer generations of boilers can reach efficiency level of 90%. Heat pumps are more efficient as they can reach a level as high as 350% and this is because they absorb thehot air outside.
Space: a heat pump requires a lot of space; this includes its outdoor fan unit which can take up as much space as a washing machine, space for its indoor heat exchanger and a hot water cylinder. This is for an air source heat pump; a ground source heat pump will require double that amount of space. A natural gas boiler requires only an indoor component which does not take up as much space.
Maintenance: gas boilers are required to be checked annually by an HVAC professional, to ensure safety by reducing the risk of carbon monoxide poisoning and explosion as a result of a leak. Heat pumps, on the other hand, are not required to be checked annually, they can operate just as well without annual maintenance.
Environmental Friendliness: a heat pump is eco-friendlier because it does not burn fossil fuel and, even if it were powered by electricity generated from coal, it still would not emit as much carbon as a gas boiler.
A heat pump costs considerably more than a gas boiler, an air source heat pump can cost four times more than a gas boiler, while a ground source heat pump costs about six times more. In places where electricity rates are lower than gas, the running cost of a heat pump will be lower than that of a gas boiler. So, before deciding on which is cheaper, it is better to consider all the factors that have been highlighted above as well as the size of the home and also take into account that a heat pump can provide cool air during summer months.