Single room heat pumps can be a simple a low cost solution.
The government recently announced that householders can get a grant of £7500 towards installing a “whole house” heat pump to replace their gas or oil-fired boiler.
This is good news because heat pumps are a low carbon technology, 3.5 times as efficient as an electric fan or convector heater (consuming one unit of electricity to produce 3.5 units of heat). However, some people are reluctant to replace their boiler with a whole house heat pump, because:
The house is poorly insulated
The location (eg. mid terrace or flat) makes installing a whole house heat pump challenging
They are unwilling to trust a whole house heat pump as their sole source of heating
They want to avoid the disruption or cost of installing a new heat pump to power their central heating.
However, a “single room” heat pump (aka reversible air-to-air split heat pump) can solve these problems. These units only provide local heating so do not replace your entire central heating and hot water system. You will have seen these units in hotels and offices but they are now available in small sizes to suit individual rooms. They cost from £500 plus installation, which is much less than a whole house heat pump.
See the table comparing whole house and single room heat pumps.
Whole-house heat pump
Single room heat pump
£500 (DIY install) to £1500 installed
Can I get £7500 government grant ?
Yes, if professionally installed
What is it?
Single external unit with air or ground source heat pump
Split heat pump unit with internal fan and external condenser
What does it do?
Heats water for central heating and hot water
Heats or cools air for local heating / cooling in 1-4 rooms (no hot water)
Does it need radiators?
Yes, or underfloor heating
None needed (warm air)
Can it cool as well?
No, heating only
Yes, it can heat as well
Can I keep my old boiler
No, you lose your fossil fuel boiler
Yes, keep fossil fuel boiler for other rooms and hot water
Can I DIY install ?
No, it’s a professional job
Yes, but only for units that use propane as refrigerant
Like whole-house heat pumps, single room heat pumps units are very efficient “electricity magnifiers” with a typical magnification factor of 3.5. However, unlike whole house heat pumps, these units are reversible, so can cool as well as heat.
With our hotter summers, many people buy portable air conditioners that have the same problem as fan heaters: you only get one unit of cooling from every unit of electricity. However, a single room heat pump will give out 3.5-4.5 units of cooling for every electricity unit.
So, if you often use an electric fan or convector - or have been tempted to buy an air conditioner to use in the summer - consider getting a single room heat pump instead. These usually need to be installed by a heating engineer (which may add £500-£750 to the cost), but some can be installed by a competent DIYer. Some models even allow you to install 2, 3 or even 4 wall-mounted fan units in different rooms all working with one external compressor unit. The only maintenance is to vacuum the filters every few months.