An air source heat pump, or ASHP, is an appliance that takes heat stored within the outside air to help warm your home. You can think of it as a reverse refrigerator for the whole building.
While air source heat pumps have a number of upsides such as using a renewable energy source to generate heat, they can also have a number of downsides such as high initial investment, so can they be considered worth it overall?
An air source heat pump can be worth it in many situations. Heat pumps can be one of the most energy efficient ways to heat or cool a home, and although they aren’t as powerful as traditional heating systems, they have a lower carbon footprint and can be implemented into existing heating systems.
We own and use an air source heat pump to provide central heating and domestic hot water for our home.
Although this heat pump was installed when the house was built in 2017 and didn’t replace any existing heating system such as gas, it has worked fantastically so far, and we would consider that an ASHP would be worth it even if switching over from a traditional heating system.
This article will explain why air source heat pumps can be worth it, discussing air to air and air to water heat pumps, their energy efficiency ratings, and the pros and cons of ASHPs.
Is An Air to Air Heat Pump Worth It?
Air to air heat pumps can be worth it when a heat pump is required for both heating and cooling a home. Many air source heat pumps can be used to both transfer heat into a home from the outside and to also cool down a home by removing heat from it.
Air to air heat pumps, which work by extracting heat energy from outside air and transferring it indoors through blown warm air, can be very energy efficient.
You’ll typically find air to air heat pumps with an efficiency performance rating of 3.0-4.0, meaning that you get 3-4 kW worth of heat energy for every kW of electricity consumed. The greater this number, the more efficient a heat pump can be.
The coefficient of performance (COP) for our own air source heat pump is highlighted below as an example for how efficient modern air source heat pumps can be.
See our articles on air source heat pump COP and air source heat pump efficiency for more information.
An air to air heat pump heats your home by blowing hot air through an air handler unit, vents, and ducts. If you have existing ducting in your home, then it can make the installation of an air to air heat pump more cost effective.
You can think of this device like an AC unit that can both heat and cool your house, by reversing the ASHP in summer to transfer hot air from the house to the outdoors.
This dual heating and cooling function is enough to make air to air heat pumps worth it alone.
Note that air to air heat pumps can’t provide radiating heat. They can only warm the air up.
Air to air heat pumps also can’t be used to provide domestic hot water and so may need to be used alongside a more traditional boiler system to provide hot water for taps etc.
On the one hand, warm air feels good to us and can quickly warm you up. But on the other hand, it won’t heat the room directly, and it takes a long time for warm air to fill larger spaces.
Is An Air to Water Heat Pump Worth It?
Air to water heat pumps can be worth it when you have an existing or new water-based central heating system. An air to water heat pump can be used with a hot water storage tank and underfloor heating and/or radiators, and can also be used to provide domestic hot water.
Air to water heat pumps can be even more efficient than an air to air versions because liquid can be better at holding and transferring heat than air.
Our air source heat pump is the air to water type and transfers heat from the outside air to a hot water tank inside our home through refrigerant in pipes.
It’s from within our utility room cupboard where the hot water cylinder tank and other apparatus is located that water is heated and used for both central heating and domestic hot water.
Our air to water heat pump works with radiators and underfloor heating across our home to deliver the heat. See our articles on using air source heat pumps with radiators and with underfloor heating for more information.
A downside to heat pumps is that the heat isn’t as instantaneous as traditional gas heating systems and so the heat must be extracted and released over a longer period of time to reach the same temperatures.
Air to water heat pumps may not be able to reach the hottest of temperatures desired for domestic hot water and may only be able to reach a maximum temperature of around 131°F (55°C).
Hot water tanks (like ours) used with air source heat pumps are therefore typically fitted with electric immersion heaters to help bring up the water temperatures when demand in the house requires it.
For more information see our articles on using air source heat pumps with hot water tanks and using air source heat pumps for domestic hot water.
Additionally, air to water heat pumps are more effective in homes with a good level of insulation as they need time to release the heat.
See our article comparing air to water and air to air heat pumps for more information.
Are Air Source Heat Pumps Energy Efficient?
Air source heat pumps are one of the most energy efficient ways to heat a house. Air source heat pumps transfer heat from the outside air and don’t just convert electricity into thermal energy, making it more efficient than electric space heaters and fossil fuel heating systems.
An air source heat pump system can completely replace or repurpose your existing HVAC system and can be more power efficient to run an ASHP for both heating and cooling around the house.
Air to water heat pumps can be 3 to 5 times more energy efficient than electric water heaters. Air to air heat pumps may not be as efficient, but they’re still much better than an oil or gas furnace.
We can say that an electric water heater is 100% efficient because it converts all electrical energy into heat. So, how is an air source heat pump more efficient than that?
An air source heat pump doesn’t convert electricity into heat. Instead, it uses the energy for the vapor-compression refrigeration process to power the compressor, coils, and fans.
An air source heat pump extracts heat already present within the outside air, which is in contrast to traditional gas or oil heating systems that need to generate heat from a different energy source.
Pros And Cons Of Air Source Heat Pumps
Since air to air and air to water heat pump systems are different types of air source heat pumps, it’s best to look at each of them separately.
Both have a few unique pros and cons that can help you decide which is best for you.
Pros and Cons of Air to Air Heat Pumps
Air to air heat pumps have several benefits, such as:
- Energy efficiency.
- Can heat the house up quickly.
- Can use existing air ducts and vents.
- Efficient at both heating and cooling.
- Works great for smaller spaces.
- Low maintenance.
- Long lifespan.
Air to air heat pumps also have a few downsides when stacked against air to water heat pumps and traditional furnaces. These include:
- Can’t heat up larger areas effectively.
- Can’t keep you warm during blackouts.
- High installation costs if you don’t have air ducts.
- Fans can get noisy as they age.
Pros and Cons of Air to Water Heat Pumps
Here’s the reasons why you would upgrade to an air to water heat pump:
- Extremely energy efficient.
- Provides radiating heat throughout the house.
- Can be used to provide domestic hot water.
- Long lifespan.
- Can heat up large areas.
- Can be adapted to existing water heating tanks and radiators (in most cases).
However, there are also some downsides you’ll need to consider before making a final decision. These include:
- Requires good thermal insulation for the house.
- May require electric immersion heater to help increase domestic hot water temperatures.
- Fans can get noisy as they age.
- High installation costs.
- Doesn’t work as well in extremely cold weather.
See our main article on the pros and cons of air source heat pumps.
Are Air Source Heat Pumps Worth It?
Air source heat pumps can be worth it when thought of as a long-term investment.
With traditional heating fuels such as gas and oil rising in price and looking to be phased out, an air source heat pump can be worth installing if you’re looking to help save money over the long run and help reduce your carbon footprint.
Air source heat pumps can have their downsides such as not being able to generate instantaneous heat, but these can be solved by a local installer who will help ensure that an air source heat pump can work just as well as any traditional heating system.
Our air source heat pump came with the house but had we replaced a gas heating system with one then it would still have definitely been worth it.
Further Reading
Are Air Source Heat Pumps Cost Effective?
How Long Does An Air Source Heat Pump Last?
How An Air Source Heat Pump Works
Parts Of An Air Source Heat Pump Explained