The climate crisis issue that no one is talking about? Your gas boiler

For the first time ever, the UK electricity mix featured more renewables than fossil fuels. But around 85 per cent of homes are still heated by carbon-heavy natural gas


A decade ago, gas and coal generated more than 70 per cent of the UK’s electricity. Now, for the first time since 1882 – when the world’s first commercial coal-fired power station opened in London – renewable energy sources have provided more electricity to UK homes and businesses than fossil fuels.

The milestone, set in the last quarter of this year, comes after the UK smashed the record for generating electricity without coal, going cold turkey for 18 straight days in May.

Heating makes up 40 per cent of the UK’s energy consumption with 85 per cent of UK households being heated using fossil-fuel based natural gas. Fourteen per cent of UK greenhouse gases come from our homes, a similar level to emissions from cars.

The Committee on Climate Change (CCC) – an independent body that advises the UK government on tackling climate change – has proposed that by 2025 no new homes should be connected to the gas grid. Joanna Furtado, lead author of a report by the think tank Policy Connect on the state of the UK’s heating systems, says the target is admirable, but only tackles a tiny proportion of the problem. “Eighty per cent of homes which exist now will still be in use in 2050, So that’s a massive amount of buildings which need to be retrofitted,” she says. To meet a target of an 80 per cent reduction in emissions more than 20,000 homes a week must switch to low-carbon heating between 2025 and 2050. (The net zero target requires an even larger commitment.)

Switching to lower carbon fuels would reduce the environmental impact of heating – just as the switch to renewables has shifted the UK’s electricity mix towards cleaner energy. “If there was a source of low-carbon gas that could provide similar amounts of overall energy and at a similar price to fossil gas – then policy would undoubtedly have been accelerating towards this as the go-to solution,” says Wilson. “However, because no such low-carbon gas exists at a scale and price (and with the requisite standards for safety) – policy is rightly weighing up the advantages and disadvantages of different heating technologies.”

The UK has multiple options, says Furtado. One is switching over to hydrogen, a low carbon gas, which would require your street, connected to one bit of the gas grid, all switching their homes from having natural gas boilers to hydrogen boilers. (Furtado urges caution on this solution however – it hasn’t actually been shown to work yet.)

Another are heat pumps, which run on electricity and draw warmth from the environment. Countries such as Switzerland already use heat pumps, but they are not widely deployed in the UK, mainly because our buildings are so energy inefficient. There are also hybrid pumps, which work like heat pumps, except that in the coldest, peak-demand months of the year energy switches over to a natural gas boiler (or potentially hydrogen boiler.)

Better insulation is also key to reducing our need for heating in the first place. Heat pumps, for instance, are only useful if homes are so well insulated they only require a small amount of heating. “That’s massive, regardless of what heating technology you end up with,” says Furtado. “The CCC suggested that all buildings would need to reduce their demand by 25 per cent, which is quite a large amount. So energy efficiency is completely crucial to meeting our net zero target.” A report from the CCC, estimated that it would cost £4,800 to install low-carbon heating in a new home, and £26,300 in an existing house.

One added problem is that the UK’s reliance on natural gas boilers is fairly unique in Europe. Natural gas boilers are particularly prevalent in the UK, along with the Netherlands, due to our natural gas reserves in the North Sea. It has always made historical sense for us to use gas, says Furtado. “In other countries that didn’t have those resources, they were dependent on things like oil for heating, or coal,” she says. “Putting in things like heat pumps made a lot more sense in places like Switzerland. So it’s quite hard to compare, because there’s been all these different geopolitical factors at play”.

She says that Denmark’s approach, however, is interesting. “Around 70 per cent of homes are heated by the district heat network,” she says. “Certain areas were moved off the grid, and went on the district heat network, but each one was owned by a kind of a community operative or the local authority that basically meant that the heat was really low cost.”

Although the route to decarbonising our boilers isn’t exactly clear, Wilson says that it’s time that we started paying a little more attention to our looming heating problem. The switch to green sources of electricity and transport is already well publicised, he says, but heating has lagged behind. “Heat is the one that we’re all hopeful provides more interest just so people understand, that things are likely to change and perhaps change significantly over a period of time.”