Heat pumps are the UK government’s preferred low carbon replacement for gas and oil boilers. If you are a homeowner, you will probably qualify for the grant towards the cost of installation through the Boiler Upgrade Scheme (BUS).
Heat pumps may be relatively new in the UK, but they are in use more widely in other countries in Europe, including ones with colder weather than the UK like Sweden. Here are some examples of things to think about when considering a heat pump.
You need a good installer
The key to success with a heat pump is to find a good supplier who knows what they are doing and can design and install the heat pump system to work efficiently and effectively in your house. Designing and installing a heat pump system is not as simple as replacing an existing gas or oil boiler with a heat pump. It needs different expertise, which is in short supply in the UK at the moment.
There are different types of heat pump
There are various types of heat pump, including taking energy from the air, the ground or from water. The heat pump might heat water to circulate in a heating system or heat air in vents. They need electricity to run. Here we are referring to the most common installations in the UK which use energy from the air to heat water which circulates in a central heating system. They also heat hot water in a cylinder.
Heat pumps work differently to gas and oil central heating
Heat pump systems work best if they produce a steady temperature throughout the house rather than heating specific rooms on demand. You will have a nice cosy house throughout.
Generally, heat pumps will provide hot water for your heating system at a lower temperature than a boiler. This means you probably need a larger area for your heat emitters (usually radiators or underfloor heating). You may need to replace some radiators to increase their size. Wet underfloor heating is a good option if you have this already or are planning a bigger renovation to include underfloor heating.
The flow rate around your system is important. You need the water heating your house to flow around providing heating and then return to the heat pump system to be reheated without reducing too much in temperature. This is an example of why you need an installer who can design an appropriate system for your house.
The heat pump efficiency of the installed system is very important
The efficiency of a heat pump system is specified by the seasonal co-efficient of performance (SCOP). An efficiency of 3 or 4 is achievable and important as this will keep your electricity use reasonable. This is 3 or 4 times more heat energy produced than the electricity used to run the heat pump, so more efficient and lower cost than using direct electrical heating in your house. A poorly designed or installed system may not work efficiently and cost more in electricity to run.
Where to put the outside and inside components of your heat pump
Part of your heat pump system will need to be installed outside. There are rules about where this can be installed without needing planning permission. These rules are under review at the moment. Your heat pump can be installed alongside the wall of your house or further away somewhere else in your garden if this is more convenient. You cannot have it too close to your neighbours’ windows in case it disturbs them. Heat pumps make a low noise when running.
You will also need some components inside, perhaps in your garage or utility area. Heat pump systems also include a hot water tank. This may be something new to find space for if you have a combi boiler producing hot water on demand. Heat pump systems can work with vented and unvented hot water tanks. Most new homes with a hot water tank have unvented hot water systems, but older homes might have vented systems with a cold-water tank in the loft. If you have a cold-water tank in the loft, you may be able to stop using this and use cold water direct from the mains instead, depending, for example, on your mains water pressure and whether you want to change the plumbing configuration in your house.
Where to see a heat pump installation
If you haven’t seen a heat pump system installed, it’s well worth arranging a visit to see one.
NESTA visit a heat pump scheme
Find out more:
Energy Saving Trust – heat pumps
Centre for Alternative Technology – heat pumps
Centre for Sustainable Energy – heat pumps
Low Carbon Oxford North – heating and controls
Cosy homes – air source heat pumps