The Disadvantages of Air Source Heat Pumps

Written-by

Janet Richardson

Reviewed-by

Richard Burdett

Updated on

Dec 31, 2025

The Disadvantages of Air Source Heat Pumps

Air source heat pumps can be a fantastic way to generate heat for your home but there are some caveats. Heat pumps are often better for the environment and cost effective; delivering significantly lower direct emissions at the point of use and cost savings. While they come with a wide range of benefits, everything has a set of disadvantages – and air source heat pumps are no exception. Make sure you take some time to read through the disadvantages here before you decide if a heat pump is right for you. 

Maintenance

Generally, you will find that heat pumps will come with manufacturer’s parts warranty that typically lasts between 2 and 7 years, depending on the brand. You can also get workmanship warranties, which tend to last for up to ten years through schemes such as QANW (Quality Assured National Warranties). You may also have the option to extend your warranty, a feature that many manufacturers will offer at an additional cost. Generally speaking, these can be extended for up to 10-12 years, but they will require regularly scheduled maintenance. This will normally consist of an annual professional service.

Your installer should leave you with clear written details that note any maintenance checks that you will be expected to undertake at any given point during your ownership. This will ensure that things run smoothly and consistently throughout its lifetime. You should always make a point of speaking to your supplier for the exact maintenance requirements before you decide to commit to the purchase of a heat pump. It is highly likely that you will be asked to carry out yearly checks on things like the air inlet grill and evaporator, just to ensure that they are free from leaves and debris. You will also need to remove any plant life that has started growing there.

Your installer may take steps to advise you about checking the central heating pressure gauge in your home from time to time. If this is the case, you should be shown how to do this, so make sure you ensure your installer follows through. This is to prevent damage caused by low system pressure or freezing conditions, rather than directly preventing freezing through antifreeze alone. Most domestic ASHP systems use antifreeze in the external circuit, which is checked during annual servicing by a qualified engineer. If your heat pump has external refrigeration pipes (rare in modern domestic systems), they will require an annual service from a refrigeration engineer. 

The Cost of Air Source Heat Pumps

It is important to understand the cost of an air source heat pump before you get too involved. Like many heat pumps, they can be a little pricey to purchase and have installed. For a typical pump, you are looking at the price ranging from £7,000 to £13,000, and prices can go up to £15,000 to £18,000 for more complex installations or larger properties.

When it comes to the running costs, these will tend to vary depending on things like the size of your home as well as the amount of insulation. The latter of these is an essential aspect when it comes to the costs and overall efficiency of the system.

The Disadvantages of Air Source Heat Pumps

The main disadvantages associated with air source heat pumps are listed below:

• Lower heat supply compared to oil and gas boilers, as they operate at lower flow temperatures, so larger radiators could be needed (heat pumps do not produce less heat, but deliver heat at lower temperatures over longer periods)
  Generally, if radiators are doubles and the pipework is 15mm not microbore, the CH system may not need many changes. 
• They perform better with underfloor heating or warm air heating and work more efficiently when coupled with larger radiators
• They can take quite some time to heat up
  Heat pumps are designed to be on most of the time, to create an ambient temperature. Due to this, starting one up from cold will take longer to heat the property than a standard combustion boiler. 
• Air source heat pumps may not lower your heating bill if you're on gas mains
  Although ASHP systems are up to 3-4x more efficient (in terms of COP) than gas boilers, gas is typically 3-4x cheaper per kWh, so the potential savings of switching to an ASHP from a modern gas boiler may not be that much without good insulation or smart tariffs.
• They need electricity to be powered if there is no access to solar energy or wind power
  As stated above, electricity is expensive. Make sure you understand the running costs when looking to install an ASHP. 
• You would need a highly insulated home to reap the high energy savings benefits.
  Heat pumps are suitable for both modern and older properties, but although there are now high temperature heat pumps, you will often need to improve your home’s energy efficiency for a heat pump to work effectively.
• Noisy like an air conditioner when it is running.
  Some ASHP systems are louder than others, there are now 'whisper quiet' systems that make virtually no noise at all. Modern ASHPs must comply with UK noise regulations, and many systems operate at 40–50 dB at 1 metre, though some are quieter than others.
• Need to run constantly during the winter, which increases electricity usage but not necessarily inefficiency.
• Less efficient in winter due to lower ambient air temperatures reducing Coefficient of Performance (COP).
• The cost of installing an air source heat pump is usually between £7,000- £13,000 before grants. 
  Even with the Government's Boiler Upgrade Scheme grant of £7500, an ASHP can cost more upfront than less green alternatives. 
• To have a high return in terms of saving from purchasing and using an air source heat pump, it is important to have a well-insulated home. 

How does an ASHP Compare to a Gas Boiler?

Electricity Tariffs and Smart Controls

The running cost of an air source heat pump is heavily influenced by the electricity tariff and control system used. Unlike gas boilers, which typically operate in short bursts, heat pumps are designed to run for longer periods at lower temperatures. This makes them particularly well suited to time-of-use electricity tariffs, where electricity is cheaper during off-peak hours.

By using smart tariffs and heating controls, homeowners can significantly reduce running costs. Weather compensation controls automatically adjust the heat pump’s output based on outdoor temperatures, improving efficiency and comfort. Smart thermostats and zoning controls allow different areas of the home to be heated independently, preventing unnecessary energy use.

Households with solar PV systems may also benefit from using self-generated electricity to power their heat pump, further reducing reliance on grid electricity. Without suitable tariffs or smart controls, running costs can be higher, so it is important to consider these factors when assessing the overall affordability of an air source heat pump system.

Want to Know More?

Have you found yourself interested in air source heat pumps? If you want to know more then click the 'Further Reading' links on the right. If you're ready to move forward, check out our directory of approved installation companies, or simply give us a ring using the number at the top of this page and have a chat.