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Gas Boilers: What are heat pumps and how much do they cost?

Wed 19 May 2021

No new gas boilers should be sold from 2025 in order to meet environmental goals for the middle of the century, according to the International Energy Agency (IEA) think tank.

But why are they a problem - and what alternatives are available?

What's wrong with my gas boiler?

It may perch innocently on a wall in the corner, but your natural-gas boiler gives out emissions that contribute to overheating the planet.

So when will the the trusty boiler be consigned to the scrap heap in the UK? And what will replace it?

Step one of the process - obliging manufacturers to make boilers that can be easily switched to run on hydrogen in future - is likely in a few years' time.

Step two - a ban on the sale of new gas-only boilers - is likely to happen in the 2030s, so if you're buying a boiler now, there's no need to panic.

If by the late 2040s you're still running a clapped-out natural-gas boiler, you may be obliged to rip it out - but that's a long way ahead.

What's good about hydrogen?

Surplus electricity from wind farms at night can be used to split hydrogen from water to produce a clean fuel.

But there's a problem. The government's climate advisers say we'll be able to produce enough hydrogen to heat only 11% of the UK's homes. And these are likely to be in north-east Scotland - near wind-turbine hubs.

So do we really want to add maybe £100 to the £2,000 typical cost of every new boiler in the country if only a minority of people will actually need it?

Ministers are wrestling with that question.
 

If hydrogen won't always work, what about heat pumps?

Climate advisers anticipate that most homes in future will be warmed by heat pumps.

These devices extract warmth from the air or the ground, or from water - a bit like a fridge operating in reverse.

They are on the market already but they are costly - between £6,000 and £18,000, depending on the sort you install and the size of your home.

Heat pumps are subsidised under a scheme called the Domestic Renewable Heat Incentive. People receive payments for seven years based on the amount of renewable heat made by their heating systems.

However, MPs say people need much better incentives to have heat pumps fitted.

Depending on the type of technology used, installation can be a lot of hassle - involving fitting bigger radiators and maybe sometimes digging into floors.

What's more, heat pumps need high levels of insulation which aren't always possible on older solid-walled homes that populate many of the UK's cities.

The government's recent Green Homes Grant was supposed to help get heat pumps established. But it failed and was scrapped after six months, to the dismay of MPs who want a multi-decade scheme to help people heat their homes cleanly.

What other options are there?

Well, 14% of UK greenhouse gases come from our homes - a similar level to emissions from cars - so we have to find answers.

But in truth, there won't be just one solution to clean home heating.

  • New housing estates increasingly will be warmed by district networks of pipes supplying many homes from a single low-carbon source - a heat pump in a river, for instance.
  • In a very few places heat might come from burning wood or fuel crops, where these are readily available in the right quantities. Burning wood in home log burners may be a delight, but it will be frowned upon, particularly in cities, where the fine smoke particles get deep into people's lungs.
  • Some places, such as Cornwall, will be able to use geothermal energy - from hot underground rocks. There's already a geothermally heated swimming pool in Penzance, for instance. But such opportunities nationwide will be scarce.
  • The agency that looks after decommissioned coal mines is pushing the idea that warm water could be drawn from old mine shafts to help with home heating.
  • The nuclear industry has also recently got into the act, arguing that surplus heat from nuclear stations could prove useful.
  • Heat batteries - like giant high-tech storage heaters - will play a part. So may infrared indoor heat panels that heat the inhabitants rather than the room - these are already used in some pub gardens.

So lots of options… but be warned: the great task of shifting heating from gas will be expensive and difficult.

Politicians don't like those words much, which is why the government's Heat and Buildings Strategy, expected next month, has been so long-delayed.