As Britain’s temperature records tumble and extreme heatwaves threaten to become “the norm” in the next couple of decades, the government has been slammed for its failure to help people keep buildings cool in summer and warm in winter.

Experts point out that insulation has a dual benefit – reducing our energy bills and climate emissions in winter, and helping keep down internal temperatures in the summer.

“The beauty of insulation is that it slows the process of heat moving through walls,” said Mike Childs, head of science at Friends of the Earth (FoE). “So, in the winter it stops warmth escaping from well-insulated buildings, while in the summer it does the opposite – it actually slows heat moving into our homes.”

Some media headlines and reporting during the current heatwave have suggested that insulation is part of the problem, and that our increasingly insulated homes are designed to “trap heat” inside. But Michael Swainson, a construction expert at the highly respected Building Research Establishment (BRE), told openDemocracy that “we’re not trapping heat by having well-insulated walls”.

“Because the roof is looking at the sun, insulation will reduce the amount of heat gain from a hot loft in the summer, as well as saving a lot of heat in the winter,” he said.

Upgrading windows to double- or triple-glazing can also help in the summer, as can wall insulation, particularly for homes with thinner walls, as in the UK’s large expanse of Victorian housing stock. Swainson noted that those living in well-insulated and draught-proofed homes do need to ensure there is adequate ventilation – but for many this can be as simple as opening windows in the cooler part of the day.

Green MP Caroline Lucas told openDemocracy, there is an “insulation-shaped hole at the heart of government policy” – echoing the words of the government’s own expert advisers, the Climate Change Committee, which last month highlighted the “shocking gap in policy for better insulated homes”.

Heatwaves and a ‘drop in the ocean’

This week’s 40C-plus heatwave is likely to become “the norm” in summer within the next couple of decades, according to the Royal Meteorological Society, with extremes even higher than that.

Most heat-related deaths in developed countries occur indoors, and England has more than 4.6 million homes that overheat in summer – even before the latest record-breaking temperatures. The Climate Change Committee says that, without government action on overheating homes, heat-related deaths will triple over coming decades.

“There are no funding schemes aimed at those who own and live in their own homes. Many in this bracket will not be able to afford even basic insulation measures, such as cavity wall or loft insulation,” said Childs from FoE. Meanwhile, renters have been waiting for well over a year to find out if (and when) the government will force landlords to better insulate their properties.

The Energy Company Obligation (ECO) scheme, which makes energy companies pay to retrofit the homes of some poorer households to improve insulation and energy efficiency, is “a drop in the ocean”, according to Childs.

And, anyway, the scheme’s future is uncertain. It’s currently funded by the ‘green levy’ on electricity bills, which at least two of the leading Tory leadership candidates – Penny Mordaunt and Liz Truss – have pledged to scrap. openDemocracy asked all the candidates if, and how, they would fund the continuation of this work. At time of publication, none had answered.

Lucas told openDemocracy that “for the candidates to even float the idea of scrapping green levies, which help to fund those energy efficiency measures, is truly delusional”. She accused the government of leaving people “high and dry”, and “failing to protect those who are most vulnerable to the effects of this heat emergency”.

Shutters and ‘green infrastructure’

As well as protecting and expanding existing schemes, others point out the need to implement other measures in our homes and communities for which there is currently no funding at all.

Dr Gemma Jerome, director of green infrastructure initiative Building with Nature, told openDemocracy that in the immediate term, “we should be thinking about small interventions to help protect the most vulnerable from extreme temperatures, such as installing canopies and shutters to existing buildings.” BRE also stressed the importance of shutters (a common feature in many parts of the world) in providing winter warmth and summer cool.

Jerome also advocates much wider use of “green infrastructure”, including trees, green roofs and green walls. These provide summer shade and cooling “without even touching a brick”, as well as other benefits such as flood resilience and locking up carbon.

But these measures, particularly if they are to benefit poorer as well as wealthier communities, require a holistic approach, whereas the last decade has been one of “piecemeal schemes such as the Green Deal and Green Homes Grant, [which] have come and gone” – in the words of Jonathan Atkinson from retrofit specialists the Carbon Co-op. The result? “The rate at which we’re tackling [environmental improvements to our] homes is now just 10% of what it was a decade ago,” said Atkinson.

And while standards on overheating have finally been introduced – just last month – into new-build housing developments, there’s no such standard for the existing buildings that most of us will still be living in during the decades ahead.

It could be very different, as Atkinson says: “Retrofitted improvements not only keep homes warm in winter, they keep them cool in summer. Insulation and improved windows and doors keep warm air out, and improved ventilation systems keep us cool and our homes healthy.”

He is calling for a long-term strategic plan for retrofit – such as those announced recently in Ireland and Italy – concluding that only such a plan will “help us tackle climate change and protect us from the kind of heatwaves we’re experiencing today.”