Heat pump vs. gas furnace efficiency

Heat pump vs. gas furnace

Before we talk about what is better, what makes more economy and the stuff, we have to take a close look at what a heat pump and a gas furnace are.

A heat pump is a mechanical device that was designed to heat up your house in the opposite way as the refrigerator does. The fridge takes heat from inside its cabin and throws it in the outer air thus making your foods stay frosty. While heat pump takes heat from the outside (street) and drags it inside (house), working contrariwise. It does not produce heat, it only transfers it. Doing so, it surely uses some energy to operate, but the Coefficient Of Performance (COP) in any heat pump starts from 2.5 and gets up to 5.0.

Gas furnace and any other furnace produces its own heat while making combustion of some fossil fuel, eliminating it. It has COP no more than 97% in the best case (for condensed fuel) or up to 65% for conventional fuel (see the table below for more information).

Heat pump vs. gas furnace efficiency

Table 1. Different COPs of different furnaces.

Now let’s have a look at costs of yearly maintenance of furnaces with different fuels in pounds, average. On the top right, we have located indicator for an air-source heat pump to make a vivid comparison.

Chart 1. Annual costs per heating system, pounds sterling per year per one average system

The table and a chart above indicate that heat pumps, especially air-source ones, are the most efficient if to consider the pure money spent every average year. In the other types of furnaces, you have to purchase their fuel that can be hard to get in your particular location, you know. For instance, you may reside in an area that will not have a free access to natural gas or some particular type of the fuel will be costlier or cheaper at your local market (you have to consider that sometimes difference may be so high depending on local market conditions and a season that Chart 1 above will completely change in your region) simply because of lack of demanded infrastructure. The same is for any other type – but the only thing is for sure – it is hard to imagine that you may reside somewhere where there is no electricity (the only thing required to operate a heat pump). If you are afraid of interruptions in the supply, then allocate solar panels on your roof with a home accumulator and the problem will irregular electricity be solved forever. And – which is very important – this will additionally lower your yearly bill.

Heat pump vs. gas furnace cost

As it is seen from Chart 1, the decrease of your bill is 1.4-2.1 times when you install a heat pump as the main heating system for your dwelling. But what about its pros and cons? As not only the cost of running influences your decision on installation. In addition to unavailability of gas or other fuel, as we have already mentioned above, there may be the case when your weather is too mild – and you will actually lose from having a gas burner or electric heater.

Table 2. Comparison of heat pump gas furnace cost .

Indicator

Heat Pump

Gas Burner

Works at any weather and temperature

*

+

Leakage of any working liquid is safe

+

Does not affect air in your dwelling because

of combustion products

+


May be installed in any dwelling

+


* if to consider the normal average temperature in the UK generally, then heat pumps will most likely to operate at any weather conditions.

If you plan heat pumps as an alternative option to your current gas furnace, think twice if you reside in a very cold region (with temperatures drop below -10 °C) – maybe you will not receive the heating bill decrease through a year along, only in warmer months. On contrary, if your yearly temperature is over 0 °C, there may be no doubts about obligatoriness of installation of an air heat pump instead of a gas burner or electric heater.

However, there is a combined decision. You may use a heat pump to decrease your heating bill during a year if you will use a pump in the warmest months of a year to heat up a house (or maybe even to heat up sanitary water) – judging from the Chart 1, it makes perfect sense. You can switch on the gas heater only in the coldest months if you feel the temperature of your premise is too low for a comfortable living. Such a combination will boost your energy efficiency for sure.

In addition, there is an interesting decision: by doing an upgrade of your heat pump, you may spend a little more electricity to receive a vividly better heating performance by adding an electric heating spiral to the inner module of your one-to-air heat pump. However, this applies only to models that heat up your inner air as a conditioner does, through an established internal module, and will not be applicable for one-to-water heaters, that heat up water in your pipes.

All figures and numbers are approximate and stated for information only. Figures for your property may vary. Subject to survey.

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