Heat pumps explained: UK offers homeowners almost $7,000 to buy one. But what are they?
The UK government is offering homeowners in England and Wales £5,000 ($6,900) in new grants to install heat pumps to warm their homes and provide hot water. The move is part of a strategy aimed at making deep cuts to greenhouse gas emissions and decarbonizing the UK's power sector by 2035.
British Prime Minister Boris Johnson said the scheme was designed to bring the low-carbon heat pumps to a similar price as the boilers now widely used across the country, which run on natural gas, a fossil fuel made mostly of methane. Methane is harmful to the atmosphere and contributes to climate change.
But what exactly are heat pumps and can they help address the climate crisis? Here's what to know.
What are heat pumps?
Heat pumps look like big boxes with fans. They sit outside a building, and literally take heat from one place and pump it to another. They typically extract heat from the air or the ground, and they work like a refrigerator, but in reverse, enhancing the heat as it's delivered to a building. Pumps that source from the air are more common in urban areas.
Will heat pumps help address the climate crisis?
If you use electricity generated from renewable sources like wind and solar, which is widely available in the United Kingdom, heat pumps are basically the lowest-emissions option for heating that there is.
There is little data on the carbon footprint of producing the pumps themselves, so at the moment, heat pumps can't be considered zero-emission sources of heating. But they could potentially be in the future.
This is important in the UK, where 14% of greenhouse gas emissions come from heating in homes. The country is trying to achieve net zero by 2050, where it will emit no more greenhouse gases than it removes from the atmosphere, so addressing heating will play a big role in reaching that goal.
At the moment, the country relies heavily on natural gas for heating. More than 80% of homes are connected to the gas grid. The International Energy Agency says the world should stop installing new fossil fuel boilers from 2025 to meet net zero.
Can everyone use heat pumps?
There are some limitations to heat pumps. They work best in newer buildings that have good insulation. That's a problem in the UK, where a lot of homes are hundreds of years old with poor insulation and single-glazed windows that can leak warm air.
A lot of people in the UK also live in apartments, which can be heated with pumps if they are installed from the start, when a building is being constructed. If you try to retrofit a heat pump in an existing apartment, there will be limitations on what models are available to you. A lot of apartment owners end up using them just to supply hot water.
Will heat pumps bring energy bills down?
If you put a heat pump in a newer home with good insulation, heat pumps make a lot of financial sense. They can be expensive to buy -- typically between £7,000 and £11,000 -- but the government grant should help with purchases, and similar grants exist in several other countries too, many of them in the European Union.
If they run effectively in your home, they can bring energy bills down dramatically. According to The Renewable Energy Hub UK, heat pumps can save up to 52% on energy expenses if used just to heat homes instead of a gas boiler.
And with the energy crisis pushing gas prices to record highs, pumps are even more affordable to run at the moment.
Does the grant go far enough?
The UK has flip-flopped on its heat pump policy over the years, and climate activists had long been calling for a return to grants, so the announcement Monday evening has been welcomed. Greenpeace says the UK has the second-worst installation record in Europe.
But some researchers say the numbers presented by the government still don't add up, and the main opposition Labour Party called the plan "more of Boris Johnson's hot air."
The government is putting £4.6 billion towards the scheme, which also includes upgrading gas boilers to become lower carbon.
European climate think tank E3G calculates that the scheme is around £2 billion short, based on the government's own 2030 energy efficiency targets.
"Tackling the emissions produced by our homes and buildings, which represent nearly a quarter of the UK's contribution to climate change, is essential to meeting our net zero target," said E3G senior policy adviser Juliet Phillips, welcoming the grant.
"It is now up to the Treasury to back this plan with a comprehensive investment package. A nationwide green homes infrastructure program could create 190,000 green jobs and save households an average over £500 per year on their energy bills."
Who's using heat pumps already?
Between 2007 and the end of 2020, nearly 15 million heat pump units were installed across the 21 countries in Europe for which it has data, the European Heat Pump Association (EHPA) said. Of those, 1.6 million were installed last year, with Germany, France and Italy accounting for nearly half of those sales.
The UK has been lagging behind, however, according to Greenpeace data. Last year, the country installed more than five times fewer heat pumps than Lithuania, more than 30 times fewer than Estonia and 60 times fewer heat pumps than Norway, the Greenpeace analysis showed.
The United States is moving quickly to install heat pumps in new homes. According to the International Energy Agency (IEA), the share of heat pump sales for new buildings in the US exceeds 40% for single-family dwellings and is near 50% for new multi-family buildings. Ground source heat pumps are more common in the US than anywhere else -- accounting for more than half the 400,000 sold annually -- with sales boosted by a 30% federal tax credit in past years, the IEA said.
Worldwide, nearly 20 million households purchased heat pumps in 2019, up from 14 million in 2010, according to the IEA. Most of this growth is from higher sales of reversible units that can also provide air conditioning, it said, reflecting an increased need for cooling as well.
Despite this growth, heat pumps still meet less than 5% of global heating needs in buildings, the IEA said.