The UK will have to decarbonise domestic heating if it is to meet its 2050 net-zero targets. According to the National Audit Office, heating the UK’s 28 million homes accounted for 18% of all our greenhouse gas emissions in 2021.

The most likely, and currently favoured, solution to deliver heat decarbonisation will be heat pumps. The Committee on Climate Change says that 80% of UK homes will need a heat pump by 2050, and the government has a range of policies supporting their uptake.

In spite of this, public awareness of heat pumps is low, and perception is often negative. A survey by energy supplier Good Energy found that one in four people believe false information about heat pumps, including that they are more expensive to run than gas boilers and don’t work in cold weather. The problem has become so bad that, in March 2024, the National Audit Office recommended the government run a campaign to increase public awareness of the technology.

In this feature, we look at the technologies at the forefront of heat pump control, and how they can help improve public perception by making heat pumps cheaper to run and simpler to install.

Controls and heat pump efficiency 

Heat pumps are, generally, very efficient. A new gas boiler will have an efficiency of 85% but a heat pump can have an efficiency of well over 300%. That’s because a heat pump extracts ‘free’ energy from an external source, usually the air or ground outside a home.

The efficiency of a heat pump is determined by the flow temperature that it runs at. A lower flow temperature means a higher Coefficient of Performance (or CoP – the technical term for a heat pump’s efficiency). It’s the heat pump or its controls that determine this flow temperature.

A third of heat pumps are still installed and commissioned to operate at a fixed flow temperature. This makes the process easier for installers, but it is a disaster for a heat pump’s efficiency. The other two-thirds use a weather compensation curve, which are the settings the installer inputs into the heat pump to tell it what flow temperature to produce for any given outdoor temperature. The idea is that the colder it is outside, the hotter a home’s radiators need to be to keep it warm.

This is great for the efficiency of a heat pump if the installer gets the settings exactly right, which they won’t because it’s a nearly impossible thing to achieve. They calculate the weather compensation curve at the point of installation using the best information that they have available to them – probably a heat loss calculation they have produced for the home.

But that weather compensation curve doesn’t change if they get it wrong, and it doesn’t adjust to new information. Nor can it look at weather forecasts or factor in how the homeowner uses their heating system. This approach is better than using a fixed flow temperature, but we can do even better, and that’s where smart controls come in.

The latest generation of smart controls has been designed to work with a heat pump and can remove the need for an installer to set a weather compensation curve. Instead, from the moment they are installed, they learn how a home heats up and cools down, and how the heating system behaves. Then, they use local weather forecasts to calculate the optimal way to meet a homeowner’s comfort requirements, continuously optimising the heat pump’s flow temperature to maximise its CoP.

The outcome is a dynamic weather compensation curve, and one that is always, exactly right. This method of controlling a heat pump can increase efficiency by 17%, and that, in turn, makes the heat pump less expensive to run and better for the environment.

Making life easier 

Using smart controls that increase a heat pump’s efficiency benefits installers too as it removes the need to set a weather compensation curve. Setting the curve is difficult to do – if an installer sets it too low, the home will be cold, and if they set it too high, the heat pump will run inefficiently. Either way, you are likely to end up with unhappy customers, risking a callback that will cost you money. In fact, Passiv research found that 60% of heat pump installer callbacks were due to controls being set up incorrectly.

The latest generation of smart controls can benefit installers in other ways too. Some make the installation process easier with features such as built-in, push-fit wiring centres, saving the installer time and money. Other controls make remove the need for an installer to have an internet connection and smartphone app to complete the commissioning process. Instead, they guide the installer through simple steps using digital displays on the control units themselves, even without an internet connection.

Changing the way we think

Heat pumps can deliver better, more consistent comfort in a home, and massively reduce carbon emissions. When paired with the right smart controls, they can also reduce heating bills and are much easier to install.

As we approach the end of gas, we need to find alternative solutions to effectively heat the UK’s homes. The government recognises the need for heat pumps in the drive towards net-zero but the public needs to want them too if the transition to be successful. Smart controls have a valuable role to play in not only making heat pumps better, but also tackling some of the negative perceptions that currently exist about them.