Heat Pumps – a Hot Topic for Landlords Explained

The latest hot topic for landlords is a move to keep homes warm with heat pumps instead of traditional gas, oil or solid fuel boilers and stoves. 

Business and Energy Secretary Kwasi Kwarteng has confirmed a scheme to offer cash for boilers from April 2022 to kick start the transfer to heat pumps. He has provided £5,000 cash as a sweetener to landlords who upgrade their rented homes with the new technology. 

Air source heat pumps cost between £6,000 and £18,000, depending on size and heat output. Details of how the grant scheme will work are scant, and more information is expected later. 

While the move aims to encourage landlords to switch to heat pumps by 2035, they can keep working boilers past that date.

"As the technology improves and costs plummet over the next decade, we expect low-carbon heating systems will become the obvious, affordable choice for consumers," says Kwarteng. 

"Through our new grant scheme, we will ensure people can choose a more efficient alternative in the meantime."

Read more about the government's Heat and Building Strategy

How heat pumps work

The principle is simple. A heat pump is a fridge in reverse, taking in the available warmth from the ground or air around a home to raise the temperature to fire radiators and hot water. 

The source is renewable energy that recirculates automatically to warm air or water for space and water heating.

• The outside heat source from ground collectors is blown or pumped over a heat exchanger.
• The heat is colder than inside the home but warm enough to change a liquid refrigerant into gas.
• The gas pressure increases inside the pump, triggering a temperature rise.
• The heated gas flows over another heat exchanger, blowing hot air or pumping hot water around the home.
• The gas cools, returns to liquid, and flows back outside to restart the process.

Read more about how heat pumps work

Do heat pumps heat a home?

Landlords can see how efficiently a heat pump warms a home with two calculations provided by the technology supplier or installer. 

The CoEfficient of Performance (CoP) takes the heat delivered divided by the electricity consumed to reach that level. Although the reading is taken in a laboratory, real-life installation performance may vary throughout the year according to outside temperatures, making the reading difficult to interpret. 

A Seasonal CoEfficient of Performance (ScoP), also called a Seasonal Performance Factor (SPF), is the better efficiency indicator. Both terms refer to the same calculation. The SPF calculation is based on the technology installed in your home rather than a generic lab test. The data should be shared before installation and offers a tailored indication of what to expect in energy efficiency.

Are heat pumps cheap to run?

The technology needs electricity to shift heat from the outside to within a home. How much electricity the heat pump uses depends on the outside and inside temperatures throughout the year, the fuel you replace with a heat pump, the design and installation of your system, and other local factors like how the home is insulated. 

For a benchmark, the average SPF throughout the UK is an SPF of three or four. Air source systems have a slightly better performance than ground source installations. 

Conventional boilers deliver water to radiators at 75 degrees Centigrade,  whereas a heat pump's operating temperature is between 35 and 45 degrees Centigrade – a level that keeps running costs lower. The system you need to heat a home, and hot water depends on your draughtproofing and insulation, reducing heating costs by lessening how much heat escapes from the property.

Do landlords need permission to install heat pumps?

Most heat pump installations are carried out under permitted development rules that do not need planning permission. However, there are exceptions, so it's wise to speak to local planners before proceeding. Your installer should also complete the forms to tell your energy supplier about the upgrade.

Do I need outdoor space to install a heat pump?

Heat pumps come in all sorts of shapes, performances and sizes.

• Air-to-water pumps are the most popular and take up much less space than ground-to-water pumps.
• Ground-to-water pumps are most suitable for larger homes with plenty of outdoor space.
• Another option is an air-to-air pump suitable for most homes, flats and static caravans.

Which pump to instal depends on the size and space of your home.

Heat pumps for buy-to-let homes FAQ

What are ASHPs and GSHPs?

The terms apply to the two types of heat pumps. ASAHPs are air-sourced heat pumps, while GSHPS are ground-sourced heat pumps.

Do heat pumps work with underfloor heating?

Yes, the pump slots in to replace your existing boiler, so continue to heat the home and hot water through the current system. 

You do not have to fit a new central heating system to use a heat pump, although upgrading the surface area of radiators can make the pump more efficient and cheaper to run.

Must I change to a heat pump system by 2035?

No, landlords do not have to exchange their current boiler for a heat pump by 2035. The government is banning conventional boilers from then, but you can use the system without issues if you have a traditional working boiler.

What is a hybrid heat pump?

Not all standard heat pump installations are suitable for every home, so manufacturers have designed a hybrid system. Typically, a hybrid system is a heat pump working alongside a traditional boiler.

What happens if I don't change to a heat pump?

No penalties are imposed for failing to switch to a heat pump by 2035, but the manufacture of new traditional fossil fuel boilers will halt, and spare parts will eventually run out.