What Are the Problems with Air Source Heat Pumps?

Air source heat pumps (ASHPs) have been gaining popularity in the UK as a low-carbon alternative to traditional gas boilers. With the government offering grants under schemes like the Boiler Upgrade Scheme, more households are exploring this renewable technology. But, while heat pumps are often promoted as a key solution to reducing home heating emissions, they’re not without their issues.

They may offer a range of advantages in reducing heat emissions, but they introduce other potential issues, including performance concerns and difficulties relating to installation.

That’s not to say that these things make ASHP a bad option, these are just things that need to be considered before making big changes and investments.

 

Efficiency Drops in Cold Weather

 

One of the biggest criticisms of air source heat pumps is that their efficiency drops as the outdoor temperature falls. While modern heat pumps are much better than earlier models, they still rely on extracting heat from the outside air – and the colder the air, the harder they have to work.

When temperatures drop below freezing, the heat pump has to use more electricity to produce the same amount of heat. This means higher running costs and potentially less comfort indoors. In very cold weather, some systems also need a backup heater (usually electric), which can significantly increase energy bills.

So, while they do work in winter, performance isn’t always as consistent as people might expect, particularly in older, draughty homes that aren’t well insulated.

 

High Upfront Costs

 

Although air source heat pumps can reduce your energy bills over time, the initial cost is often a stumbling block. Installing a heat pump typically costs between £7,000 and £13,000 – and that’s before you factor in any upgrades to your home’s insulation, radiators or underfloor heating system!

Grants like the £7,500 offered through the Boiler Upgrade Scheme can help, but even with this support, many homeowners still find the upfront cost hard to justify, especially if their current boiler is still working well.

There’s also the question of value for money. If the system is not designed or installed properly, it might not deliver the savings or comfort levels promised, leaving homeowners feeling short-changed.

 

 

The Installation Process Can Be Complex

 

Unlike swapping out a boiler, installing an air source heat pump is a more involved process. It typically takes several days and may involve modifying your heating system. For example, heat pumps work best at lower temperatures, which means your radiators might need to be replaced with larger ones, or you might need to install underfloor heating to get the most out of the system.

You’ll also need enough outdoor space for the unit itself – it’s round about the size of a small washing machine and needs to be put in a well-ventilated area. In densely populated areas or flats, this can be a real challenge.

Noise can also be an issue. While newer models are relatively quiet, they do produce a constant low hum when running. This can be pretty annoying if the unit is placed too close to a bedroom window or neighbouring property.

 

Not Suitable for All Homes

 

Heat pumps work best in well-insulated, airtight homes. If your property is poorly insulated or particularly old (like many UK homes), the system will struggle to keep up, and you may find your house never quite reaches the cosy temperatures you’re used to with a gas boiler.

Improving insulation before installing a heat pump is crucial, but that adds to the cost and complexity of the project. For listed buildings or homes in conservation areas, there may be additional planning hurdles as well.

In addition, heat pumps don’t produce hot water as quickly as a combi boiler. If you have a high demand for hot water, you might need a larger hot water cylinder or an additional system to boost capacity.

Limited Installer Expertise

 

As demand for air source heat pumps grows, so does the need for skilled installers. Unfortunately, in some parts of the UK, there’s a shortage of qualified engineers with real experience designing and fitting heat pump systems.

This can lead to poorly designed installations that underperform or fail to meet expectations. A heat pump system needs to be tailored to your specific property – in terms of things like size, insulation levels, heating demand – and not every installer has the experience to get this right.

Always check for installers certified by the Microgeneration Certification Scheme (MCS), and be sure to get more than one quote and a detailed heat loss calculation before going ahead.

 

Slower Heating Times

 

Traditional gas boilers heat a home quickly, delivering near-instant warmth. Heat pumps, on the other hand, operate more slowly and steadily. They’re designed to keep a home at a consistent temperature throughout the day rather than quickly heating a cold house.

This is a different way of thinking about heating, and not everyone gets on with it. If you like to turn your heating on only when you get home, you might find that a heat pump doesn’t heat your rooms fast enough for your liking.

Using a heat pump efficiently often means keeping your home at a steady temperature all day, which can feel counterintuitive to those used to turning heating on and off to save money.

 

So, Yay Or Nay on ASHP?

 

Air source heat pumps can play a big role in reducing our reliance on fossil fuels and cutting carbon emissions from heating. But they’re not a magic bullet. As we’ve seen, they come with a number of potential drawbacks – from high costs and installation challenges to lower performance in cold weather.

That doesn’t mean they’re a bad choice – far from it, in fact! But it does mean they’re not right for every home or every household. If you’re thinking of installing one, it’s essential to get expert advice, consider the suitability of your property, and weigh up the costs and benefits carefully.

Like any big home improvement decision, the key is to go in with your eyes open and realistic expectations.