Air source heat pumps extract heat energy from the outside air for use inside and can even be used for cooling where heat is expelled from indoors.
Heat pumps extract and deliver this heat more slowly compared to other traditional forms of heating such as gas boilers, and so typically need to be operating for longer periods of time to get the same heating effect.
Whether an air source heat pump runs all the time can depend on factors such as outside temperatures. In very cold climates, an air source heat pump can be running all the time because less heat energy is available in the air. In milder climates, heat pumps can run intermittently.
We live in a milder climate (UK) where temperatures aren’t too extreme. As a result, our air source heat pump doesn’t run all the time as it doesn’t need to.
It does however run more frequently in colder months, but still not continuously.
We discuss in more detail below about why some air source heat pumps may need to run all the time, what factors affect how often and long a heat pump operates for, and more about what they are and how they work.
Does An Air Source Heat Pump Run All The Time?
Just like your refrigerator has more work to do in hot weather, and for the same reason that cold water takes longer to boil than hot water does, a heat pump doesn’t need to work as much when there isn’t a huge difference between indoor and outdoor temperatures.
When there’s less of a temperature difference, an air source heat pump doesn’t need to work as hard to extract heat and therefore won’t need to be running all the time.
Furthermore, an air source heat pump (ASHP) produces a lower volume of warmth than a gas furnace or boiler system.
When put together, these things mean that the colder it is outside, the longer your heat pump will have to run to keep your home warm at your preferred temperature.
As we live in a milder climate where the temperature difference between the outside and indoor air is never too great, our air source heat pump doesn’t need to run continuously.
We do however find that our ASHP runs for longer when:
- Temperatures are colder outside, such as throughout the winter months.
- We raise the desired indoor temperatures using the thermostats.
- There is a higher demand for hot water and heating.
If an air source heat pump is running all the time even when temperatures outside aren’t too cold, the indoor temperature isn’t set to high or there is little water demand then a technician may need to take a look at it to diagnose any issues.
Downsides Of Air Source Heat Pumps Running All The Time
Downsides to heat pumps revolve around the difference in indoor and outdoor temperatures. The colder it gets outside, the less efficiently your heat pump will perform because there’s less heat energy within the air.
Air source heat pumps only run on electricity and so if electrical energy prices are high in your local area then you could be looking at an increased energy bill if it’s running all the time.
In colder climates, homeowners may even need another additional heating system for those times of the year where temperatures reach lower than what a heat pump can operate at
Temperatures even colder (-15° F) can cause the heat pump to shut off completely. For example, our own heat pumps only works down to -20° C.
Air source heat pumps can also be relatively noisy.
If an ASHP needs to run all the time due to cold weather, then it can mean a continuous noise created by the fans and the compressor.
Therefore, external heat pump units are ideally located in a more secluded outside area of a home, such as down the side of the house, where there aren’t any windows nearby, and is located further enough away from neighboring properties.
See our articles on air source heat pump noise and where to install an air source heat pump for more information.
What An Air Source Heat Pump Is
At its most basic, a heat pump can be a way to heat your home more efficiently than with a furnace or electric heating unit.
By using the warmth stored naturally in outside air and moving it indoors, an air source heat pump is able to transfer heat from a renewable energy source to be used inside properties for space heating and also domestic hot water if required.
How An Air Source Heat Pump Works
An air source heat pump forces air over refrigerant flowing through the unit for heat energy to be captured and sent indoors for use.
- Fans force air over a heat sink-like series of tubes where the refrigerant is flowing through.
- The liquid refrigerant warms up and evaporates into gas form.
- The gas refrigerant moves to a compressor, which raises the pressure. As pressure increases, so does temperature.
- The now-heated gas gets routed to a heat exchanger, which transfers (or exchanges) the heat from the gas to the air or water.
- The warmed air moves out into your home and raises the temperature in your living room.
- The gas returns to a liquid as temperatures and pressures lower and the cycle is repeated.
This transfer process is much more efficient than converting heat from fuel such as a gas boiler.
Further, a heat pump can deliver at least two times more heat energy than the electrical energy it uses to do so.
That means not only fewer greenhouse gas emissions in relation to the amount of heat generated in a home than a gas furnace or electric heating system, but also potential energy savings when it comes to heating costs.
See our article on what an air source heat pump is and how air source heat pumps work for more information.
Should An Air Source Heat Pump Be On All the Time?
An air source heat pump is designed to run constantly when required.
Unless there’s an issue with a heat pump, it can be common for a heat pump to run continuously where outside temperatures are low and/or demand for heating and/or hot water is always high.
Does An Air Source Heat Pump Run All The Time?
Air source heat pumps extract heat from the outside and the greater the temperature difference between inside and outside, the longer it will need to run for.
In very cold climates, or where there is a high demand for heating and/or hot water, an air source heat pump can be running all the time if it needs to, but this shouldn’t be a cause for concern.
Further Reading
Air Source Heat Pump Enclosures
Can You Cover An Air Source Heat Pump?