As the energy crisis rages on amid rising gas prices, UK householders are facing a change in the way we heat our homes to tackle climate change. Here are some answers to the key questions about one of the main technologies we could use instead of gas boilers.
First, what is a heat pump? In short, an air source heat pump looks like an air conditioning unit on the outside of buildings, and it works a bit like a fridge in reverse, using electricity to extract energy from the outside air to provide heating for homes and hot water.
There are also heat pumps that draw energy from the ground or water.
Because they are extracting heat from the environment – which they can do even at low outside temperatures – they produce around three times the energy they use, making them much more efficient than a gas boiler.
British electricity is increasingly powered by low carbon sources such as wind, making heat pumps a clean alternative to burning gas, while they also cut local air pollutants such as nitrogen dioxide that boilers emit.
While costs vary, installing a new system can cost around £10,000 on average.
It is still a niche industry and it is expected costs will fall as the technology becomes more mainstream, with Octopus Energy saying it expects to nearly halve the cost within 18 months.
A coalition of businesses, green groups and anti-poverty campaigners has called for an upfront grant – similar to those for electric cars – that covers the full cost of heat pumps for low income families and brings it down to the same cost as a new boiler for other households, to drive the rollout.
Another option could be a financing package where your heat pump and energy are provided by your supplier and you pay a monthly instalment to reflect that – rather than an upfront cost.
How different are they to run?
The main difference is you do not get that immediate boost you can get with gas, when you feel cold and you fire up the boiler.
That is because a heat pump heats water in the radiators to a lower temperature than a gas boiler so it warms a house more slowly.
But with a heat pump, the system works out the most efficient way to keep the house to the temperature you want it and gets on with it.
You can programme in changes such as being away for holidays and your return time, so the house will be warm for you when you come back.
All heating technologies work more efficiently and save you money if your home is well insulated, and improving insulation to save energy is a key part of cutting emissions from buildings.
Heat pumps work well in homes which are already reasonably well insulated, while if you live in a leakier house, such as a Victorian terrace, putting in some measures such as loft insulation and double glazing could help keep costs down in running a heat pump – just as they would if your home is heated by a gas boiler.
What other changes might I need to make, such as swapping out radiators or putting in underfloor heating?
Because radiators on heat pumps operate at a lower temperature than with gas, you might need to swap out a few of the oldest, single panel radiators your home might have to ensure they are big enough to heat the room sufficiently.
They can normally be replaced with double or triple panelled radiators that fit in the same spot.
Underfloor heating works very well with heat pumps as it operates at a lower temperature than radiators, so it will continue to work if you have it, or if you are doing a wider refurb you could think about putting it in. It is not necessary to install it, however.
Currently, you do need a water tank for heating up your hot water, although new technology which stores heat for hot water in other ways could change that.
Do you save money from running one?
While there are some “time of use” tariffs which allow people to use the electricity for running their heat pumps when it is off peak and therefore cheaper, most people will not be saving money at the moment.
That is because, although heat pumps use much less energy to create the same amount of heating, electricity is around three times the price of gas.
Part of the issue is that there are higher environmental levies on electricity than gas, adding 23% to electricity bills and less than 2% on gas, to pay for things such as subsidies for renewables which were brought in to help clean up the electricity system.
Now the grid is much greener than it was, the pressure is on the Government to rethink where those levies fall.
They could shift some of them onto gas which would make no difference to the average dual fuel customer, but there would have to be measures to make sure fuel poor households who struggle to heat their homes already do not suffer more.
Or they could move them into general taxation.
When my boiler breaks all I want to do is get the heating and hot water back on as quickly as possible. How easy is it to switch to a heat pump quickly or do I need to plan for it?
At the moment, if your boiler breaks, you probably just ask your plumber to replace it as quickly as possible.
A long-term target to phase out boilers could help people know a change is coming, so they can have conversations with their plumbers during the annual service about the alternatives for old boilers that soon need replacing.
If you are hit by an emergency, there could be potential for installing a temporary boiler for a few weeks while you plan for a heat pump, while any application time for upfront grants needs to be short and simple, to ensure people can make the most of it, industry experts say.