What Is An Air Source Heat Pump (How They Work)

Heat pumps have revolutionized energy efficiency as they don’t utilize a fuel source but rather pump heat in or out of the space depending on whether heating or cooling is required.

An air-source heat pump is one of the newer developments in heat pump technology that uses the external air as a heat source and is reversible to allow heating and cooling within a home. This technology is super-efficient and works well in low-temperature environments as well.

To better understand this type of technology, let’s look at some of the key points:

  • How the air source heat pump works
  • How much money an air source heat pump can save
  • The advantages of an air source heat pump
  • Disadvantages of an air source heat pump

Before you spend any money, let’s explore this technology a little more and see whether these are worth the investment.

Air source heat pumps outside a house

How Does An Air Source Heat Pump Work?

The air source heat pump or ASHP transfers heat from the outside air to inside space, like a reverse refrigerator, so here is how the ASHP heating cycle works in three simple steps:

  1. The air outside is moved or blown over a series of tubes filled with liquid refrigerant, which converts the refrigerant to gas and increases its temperature.
  2. The gas then travels through a compressor, which heats it as it moves through the unit, like when you pump your bike tires, and the air hose gets hotter.
  3. The heated gas then passes over a heat exchanger, which removes the heat from the gas and converts the gas back into its original liquid form so the heating cycle can start all over again.
  4. That extracted heat is then pumped into the space in the home to warm it up.

This cycle occurs when heating is required; the cooling cycle is similar, operating in reverse, removing heat from home and providing cool air instead.

What Kinds Of Air Source Heat Pumps Are Available?

There are three types of air-source heat pumps, the air-to-air heat pump, the air-to-water heat pump, and the hybrid heat pump.

The air-to-air heat pump is the system that provides warm or cool air in the home only, while the air-to-water system is designed to provide heating for both air and water.

Using this type of heat pump would provide hot water in the home and further reduce energy costs.

There is also a hybrid heat pump that can combine with an existing boiler and central heating unit, and the existing system would switch on to add a boost of heat when needed or during severe cold snaps.

The real question with air source heat pumps is how much money they can save and how they reduce your energy costs.

How Much More Efficient Is An Air Source Heat Pump?

Right off the bat, heat pumps are more energy-efficient as they pump heat rather than using a fuel source like gas or electricity and convert it to heat, and this means they use a lot less electricity to do so.

The basics of energy conversion in a heat pump show an average of three heat units for every unit of heat produced, unlike electricity which is a one-to-one ratio of energy to heat units.

Heat pumps deliver an energy efficiency rate of 300% or more than a 100% efficiency rate for conventional heating systems.

With conventional heating using electricity, a heater would provide 1kWh of heat for every 1kWh of electricity used, while the heat pump could deliver 3kWh- 3,5 kWH for that same 1kWH of electricity used.

Adding a heat pump to your home would only add about $75 a month in terms of operational costs but would reduce your heating/cooling costs and water heating costs if the heat pump was being used for hot water.

How Much Money Could An Air Source Heat Pump Save Per Year?

Calculating the savings for the heat pump needs to consider the area and average temperatures and whether you are using it for heating and cooling only or including water heating.

As a comparison, let’s look at how much you could save using a heat pump for heating your home.

The US Department of Energy has advised that an average home using electricity for heating can save about 50% or $1000 or more per year by using a heat pump.

Not only that, but this saving equates to reducing your carbon footprint by as much a 4 tons per year as well. Hence, you get to save money and the planet simultaneously, plus many states offer incentives and rebates up to $1000 for homeowners to use more energy-efficient systems.

Let’s compare the savings from a heat pump against other heating sources and see which would save you the most by switching, and we will look at this from the most savings to the least.

Existing Heating SystemSavings With Heat Pump
Baseboard Heaters$1287
Fuel Oil$947
Fuel Oil Boiler$929
Propane Furnace$855
Electric Furnace$815
Natural Gas Boiler$199
Natural Gas Furnace$105
Heating Systems and Savings With Heat Pump

The data in this study was compiled from NREL data to show homeowners how much they could save annually by switching to an air source heat pump.

The top three savings are converting from baseboard heaters or fuel oil sources. Propane and electric furnaces offer the 4th and 5th most savings, respectively, with natural gas proving the most efficient existing systems.

What Are The Factors That Influence Energy Saving In A Home?

Aside from the obvious reduction in fuel and electricity costs, some external factors also influence how much energy the heat pump can save you.

  1. The larger the home, the more you will save.

Larger homes with square footage will use a lot of energy to cool or warm, and by switching to a heat pump, you will save more than you would if your home was smaller.

  1. The local climate

Heat pumps work from coast to coast and from the warmest to the coolest climates across the US. Still, where there are concentrations of homes – especially in the East and Southeastern USA, that currently use inefficient fuel sources like fuel oil, electricity, and propane, the savings will be much greater.

  1. The level and quality of insulation

Insulation plays a massive role in energy efficiency in your home. If you don’t have double-glazed windows and good roof insulation, then a lot of your heat, energy, and money is going to disappear through your roof and windows.

It is vital to have good quality and effective insulation on your roof. Where possible, use double-glazed or specialized glass that delivers better insulation than existing plate glass windows.

If you live in very hot or cold environments, investing in proper insulation will reduce your energy usage and increase savings even if you don’t install an air source heat pump.

  1. What heating system you are using to heat your home

From the table above, if your heating system is one of the less efficient ones – outside of natural gas – then switching to an air source heat pump will save you money and reduce your energy costs and carbon footprint.

Remember that an investment in an air source heat pump is just that. Making sure your home is optimally suited to benefits from the investment is a proven strategy for a good long-term return on investment.

How Much Do Air Source Heat Pumps Cost?

To supply and install a heat pump would cost about $10 000 on average, but it can range between $2500 and $15000, which makes it cheaper than solar, but, like solar, you need to be sure you have it installed properly.

Poor installations can result in further costs to fix leaking pipes or similar problems, so make sure you use an accredited installer and do your due diligence before appointing a service provider.

If you take the average cost of around $10 000 and then the savings of $1000 per year, you would be looking at a ten-year break-even point, but that doesn’t take into account annual increases in energy costs either, so realistically, this is probably closer to an eight-year ROI than ten years.

Your Existing System Could Save You Money Too

Depending on your existing system, the installation could be lower as the installer could utilize the existing infrastructures like ducting and piping of you will be using air-to-water in your home.

This is why it is critical to have a reputable installer to examine the existing systems and determine what they can use to reduce the costs and connections.

Linking your heat pump with existing underfloor heating and piping will prevent the need for excessive work like drilling to lay ducts and other conducting infrastructure.

How Can A Heat Pump Be Utilized For Hot Water?

You can get stand-alone heat pumps that will work solely to heat water and reduce the cost of your existing boiler. These systems stand vertically and look like a big cylinder, almost like something out of a sci-fi movie.

Installed and connected to the existing water supply system, these heat pumps effectively produce hot water. They can even be linked to underfloor heating as they produce lower temperatures than electric systems.

The best thing about these types of water heaters is that they can hold about the same volume of water as conventional boilers and are extremely cost-effective as they can supply a family of four with hot water for about $15 a month!

Other Advantages Of Air Source Heat Pumps

Outside of the energy savings, there are some additional benefits to installing a heat pump in your home.

  1. Heat pumps are healthier as they don’t use fossil fuels that could contaminate the air in your home should there be a leak, and studies have shown a link between asthma and other respiratory diseases and the use of gas or fossil fuels in the home.
  2. Using an electric heat pump eliminates the risk of fire or explosion, which is a potentially serious problem in a fire in the home or a fuel leak.
  3. Heat pumps require less maintenance than fuel oil systems, which will also contribute to the overall cost saving over a year.
  4. Heat pumps have a long lifespan of around 20 years, which means that after the initial recovery on the investment period, you would be getting back another $10 000 in savings.
  5. They can be linked to solar PV systems and increase the savings further.PV systems can power the heat pump if there is enough capacity.
  6. There is no need for fuel storage in the basement or home.

Disadvantages Of An Air Source Heat Pump

No technology is without its drawbacks, and heat pumps do have a few to consider.

  1. Heat pumps have higher upfront costs, but this is offset against savings and government energy incentives.
  2. Heat pumps are noisy and need to be installed outdoors and away from home. The noise level is equivalent to light or medium rain. Many heat pump manufacturers are working continuously to reduce the noise levels.
  3. They lose efficiency in sub-zero temperatures as this very cold air affects their ability to draw heat from the outside air, and very cold temperatures can cause them to stop working.
  4. There is an additional cost to install underfloor heating if you don’t have an existing system installed.
  5. It has a lower heating temperature than other systems, so larger radiating surfaces may be required.
  6. Heat pumps take longer to heat water, so if you want a quick bath, you may have to wait a little bit before you can have one.
  7. They depend on electrical supply, and if you live in an area where electrical supply disruptions are common, you may need to reconsider using a heat pump.

It’s abundantly clear that the advantages of the air source heat pumps outweigh the disadvantages by some margin.

Provided your home is properly set up with insulation and you get a reputable installer, adding an air source heat pump will certainly save you money, reduce your dependency on fossil fuels, and ultimately reduce your impact on the environment.


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