The pros and cons of air source heat pumps

With the UK striving for “Net Zero” carbon emissions by 2050, it’s time to turn to other ways of heating our homes. In this blog, we explore air source heat pump pros and cons

According to the Climate Change Committee (CCC), a staggering 85% of UK homes are heated by gas boilers. Worryingly, this makes heating one of the largest carbon contributors to carbon emissions at home.

To reach our national Net Zero carbon emissions target by 2050, almost all our homes need to switch to low carbon heating. But with low carbon heating in just 5% of UK homes, it’ll take us around 700 years to reach our commitment to achieve net-zero emissions.

Nevertheless, change is coming. The Committee on Climate Change stated that from 2025 at the latest, “no new homes should be connected to the gas grid”.

This powerful pledge is creating a surge in demand for air source heat pumps. The question is, should you be following suit? Here’s everything you need to know about air source heat pump pros and cons.

What is an air source heat pump?

An air source heat pump (ASHP) is an alternative way to heat your home or commercial premises. It enables you to generate your own renewable heat and potentially save money on your energy bills.

How does an air source heat pump work?

An air source heat pump takes heat from the air and boosts it to a higher temperature using a compressor. It then transfers the heat to the heating system in your home. Heat pumps work similarly to a refrigerator by absorbing heat and transferring it to another medium.

Certain air source heat pumps can also work as a cooling system in the summer months. Most commonly, they are placed outside of a building where there is adequate space for the installation.

There are two main types of air source heat pumps:

  • Air to air heat pumps, which absorb heat from the outside air and then transfer it directly into your premises to heat a room.
  • Air to water heat pumps, which absorb heat from the outside air and then transfer it via your central heating system to provide hot water, radiator, or underfloor heating in an indoor space (or all three).

But before you make the switch, there are various air source heat pump pros and cons for you to delve into.

10 benefits of air source heat pumps

There are numerous benefits to using air source heat pumps. Here are ten of the best.

Low carbon footprint

Air source heat pumps are a form of low carbon heating, as they use the outside air to heat or cool your property. If you are switching from a coal or electricity-based heating system, you can significantly reduce your carbon emissions.

Installing an air source heat pump could cut your carbon emissions by more than 23 tonnes of CO2 over 10 years. That’s the same as 30 return plane flights between Heathrow and Madrid. And with the global push to reduce our collective carbon footprint, an air source heat pump is a great starting point.

Eligible for RHI

By swapping over to a domestic heat pump, you could receive payments by generating your own heat through the Renewable Heat Incentive (RHI). By utilising this green energy grant, you can save even more on your energy bills.

Air-to-water heat pumps are eligible for the domestic RHI, and the scheme has been extended until March 2022. This means, if you install your air source heat pump within that deadline, you’ll receive payments for each unit of heat generated for 7 years.

The domestic RHI payments are calculated based on the current RHI tariffs, your heat pump’s high Seasonal Coefficient of Performance (SCOP) and your energy demands.

You can find out more about this great scheme at GOV.UK.

Suitable for domestic and commercial use

Air source heat pumps are the ideal solution for both domestic and commercial premises. For businesses, this method of heating can significantly reduce costs and increase your organisation’s green credentials.

The low-level constant heat will create a better working environment for employees too. You’ll also be shielded long term from the volatility in fossil fuel prices, which, when rising, can generate a considerable extra cost to a business.

High Seasonal Coefficient of Performance (SCOP)

Air source heat pumps are efficient both in the winter and summer, thanks to an outstanding SCOP (Seasonal Coefficient of Performance). The COP of a heat pump is a way to measure its efficiency by comparing the power input needed to produce heat to the amount of heat output. A ‘seasonal COP’ figure is adjusted to seasonality.

For example, a typical air source heat pump runs at a COP 3.2 when the outside temperature is above 7°C. This means that the heat pump is 320% efficient. Therefore, for each 1kW of electricity used by the fans and the compressor, 3.2 kW of heat is generated. The higher the COP, the better.

When considering an air source heat pump’s COP versus outside temperature, you will find that despite some slight fluctuations, they can run efficiently all year round. To be able to compare heat pumps based on how much they are affected by these efficiency changes, the seasonal COP is used.

Low maintenance

Servicing and maintenance should be done by a trusted technician once every 2 years as a minimum. As such, air source heat pumps are quite low maintenance.

Nevertheless, there are a few things you can do to ensure optimal performance of your heat pump, including:

  • Cleaning filters
  • Removing dust
  • Clearing leaves
  • Checking for system leaks refrigerant levels

For more technical tasks, you should contact a certified installer.

Save money on energy bills

By switching to air source heat pumps, you can reduce your energy bills as you’ll be using the outside air for your heating and cooling needs. Your savings will be more significant if you are going from an electric or coal-based system. Although the upfront cost is fairly high, you’ll be eligible to receive a significant portion of your investment back from RHI payments.

The running costs of heat pumps depend on a few factors, from the efficiency to the amount of heat needed and the temperature of the heat source. While they use electricity, air source heat pumps can be combined with renewable energy sources for clean electricity.

Used for heating and cooling

Air source heat pumps can be used for both heating and cooling purposes. Depending on the model, they can provide cooling in the summer and heating in the winter. All you need to check is that the COP of your air source heat pump is above 0.7 for cooling.

In addition, air source heat pumps work very well with underfloor heating. So, if you want to get the most out of your system, you should strongly consider installing underfloor heating.

Used for space heating and hot water

Many air source heat pumps can be used to heat your water, depending on the temperature of the water in the heating system (also known as ‘flow temperature’). To heat water, the flow temperature needs to be approximately 55°C. If your system is only designed for space heating, the flow temperature will be 35°.

If you’re looking for both space heating and water heating, then opting for an air source heat pump that has a flow temperature of 55°C is needed. Again, linking the heat pump to a renewable energy source is a great method of saving energy and reducing your carbon footprint.

Easy installation process

Installing an air source heat pump can take as little as two days and is quite simple as there’s no need for extensive groundwork. A domestic air source heat pump typically doesn’t require planning permission, but it is always advised to check with the local authority before you start the process.

It’s an ideal option for both retrofits and new builds. If you combine air source heat pump installation with other building work, you can bring the cost of installation down.

A long lifespan

Another pro of an air source heat pump is its lifespan. With proper maintenance, they can be operational for up to 20 years. Most air source heat pumps have multiple year warranties too, for complete peace of mind.

With several technological developments, modern heat pumps can work efficiently for close to 25 years before needing replacing. It’s quite astonishing when you consider a gas-fired boiler needs replacing at about the 10-year mark.

6 negatives of air source heat pumps

Like any piece of tech or equipment, there are some cons to consider too. After all, you need to be 100% sure this is the correct system for you! Here are six air source heat pump disadvantages you need to know.

Lower heat supply than boilers

Air source heat pumps offer a lower heat supply compared to traditional systems such as oil and gas boilers, which can get you water temperature up to 75-80°C. On average, an air source heat pump will produce water temperatures of around 45°C in comparison to 75-80°C temperatures generated by oil and gas boilers. This means that air source heat pumps are not suitable for all properties.

Lower efficiency below 0°C

Although air source heat pumps can work at temperatures as low as -20°C, they do lose efficiency below 0°C. This is because they exclusively depend on outside air, and as the temperature drops, so do the overall heat output the pump can produce.

The colder the air gets, the harder the pump has to operate. When this happens, you could well see your bills go up. Luckily in the UK, we don’t regularly see temperatures drop that low!

Air source heat pumps can be noisy

If you enjoy absolute peace and quiet, then you may want to reconsider getting an air source heat pump. While the newest models are getting quieter, most will still make a humming noise. If you are concerned, you could always ask the technician to install the unit away from bedrooms and main living areas. However, this may harm system efficiency.

Your premise must be well-insulated already

To reap the full benefits of an air source heat pump, you’ll need a well-insulated premise to begin with. Although, this minimum requirement applies to any heating system.

If heat can easily escape from your home through windows, doors or walls, then you’ll need more energy to keep the space warm. Therefore, ensure your home is well insulated and draughts are kept to a minimum to reap the full energy-saving benefits.

Extra spending to install underfloor heating

Underfloor heating is a great partner to an air source heat pump. The efficiency of an air source heat pump increases as the required flow temperature decreases. Put simply, this means that the cooler you can run the system, the less it costs to operate.

If properly designed and installed, underfloor heating can run at very low temperatures. This makes underfloor heating and air source heat pumps a perfect combination for UK households. But this will mean that your installation costs may be higher if you do not already have an underfloor heating system installed.

Higher running costs

If you have an A-rated gas boiler, that is relatively new and regularly maintained and serviced, you may find there is little (if any) difference in your overall heating bills. However, the future of the UK is focusing on increasing heat pump installations significantly and you can expect to have more low carbon incentives to make the switch.

Should you switch to an air source heat pump?

Now you know t air source heat pump pros and cons, it’s up to you to make the all-important decision. If there is one thing to take away from this, it’s that this green form of energy is not perfectly suited for every building.

But if you have the space, are planning a new build or have the right central heating system already in place, then an air source heat pump could save you money, keep you warm and reduce your carbon footprint. And that certainly makes this renewable energy source worth considering!

If you are ready to invest in an air source heat pump or need some guidance on choosing one, we are here to help. Contact Mid-Tech today. In the meantime, follow our journey on LinkedInFacebook and Instagram for more handy insights.

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