Heating bills might seem less of a concern as temperatures rise, but recent figures show the number of homes overheating in summer has quadrupled to 80% during the past decade – which should be equally worrying.

UK buildings largely aim to protect from the cold and can’t deal with the extremes of heat we’ve seen in recent years; according to a University of East London study, those built after 1900 are twice as likely to get overheated along with those (probably very well insulated) with an EPC band A or B. Although EPCs now take overheating for new-build residential buildings into account under Part O of Building Regulations, existing buildings aren’t covered. But while it’s not explicitly outlined as part of the UK government’s consultation into EPCs, Energy Assessors should certainly consider thermal comfort and overheating when surveying existing buildings.

These problems aren’t confined to the domestic sector, as high temperatures also make commercial buildings impractical and uncomfortable to work in – and for those living in office-to-residential conversions. It’s particularly pertinent as Rightmove data shows the number of enquiries to lease office space is at its highest point since pre-pandemic – 19% higher than the same period a year ago – with many firms wanting employees back in the office more regularly. While that’s got to be a good thing for landlords, the experience back at their desk isn’t always pleasant. The platform quizzed workers on what would entice them back and was told by 27% that office temperature was one of the most frustrating things about their working environment, clearly highlighting why older, energy-inefficient and less comfortable office spaces can struggle to attract tenants or meet office workers’ expectations.

Too many offices, warehouses and shops fail their staff and customers. More than 13,000 commercial rental properties available for rent in England and Wales still have EPC ratings of F or G, failing to meet the currentMinimum Energy Efficiency Standards of EPC band E. Offices are the worst offenders, with nearly 5,761 buildings still rated F or G, nearly 5% of total stock, says commercial real estate data and technology company, Search Acumen, which suggests it’ll take until at least 2040 for all rented commercial properties to meet the potential MEES standard of EPC B or higher. That’s going to be way too late if the Department for Energy Security and Net Zero (DESNZ) finally confirms that commercial landlords will have to reach EPC B under non-domestic MEES regulations by either 2030 or 2031.

While the imminent DESNZ decree should prove the much-needed stick for many commercial landlords to act, it’s heartening that those who are more clued-up aren’t waiting for the government to legislate but instead are targeting net zero and making green improvements regardless. They realise it’s a great way to attract good tenants keen to rent buildings with strong environmental credentials, as well as to secure an income stream, and add value to an asset by boosting its rental profile. Working towards net zero should be front of mind for all landlords, to lower the environmental impact of the built environment, and ensure portfolios remain commercially sustainable. It’s sensible to incorporate overheating risk into retrofit plans, so using data sensors can be a good way to keep on top of temperature spikes. Having them installed long-term doesn’t just keep tabs on damp and mould in the colder months but can also capture data during the summer when there’s a risk of overheating.

Air conditioning might seem like a solution (particularly when some increasingly popular heat pumps – air to air models – also work as air conditioners); indeed, the UEL study found that the use of air conditioning units increased sevenfold to 21% of homes between 2011 and 2022. However, these can also drive up energy consumption, increasing greenhouse gas emissions, putting pressure on energy supply and boosting bills. Instead, improving ventilation and factoring in passive cooling such as shading and insulation are worth considering when advising on energy efficiency improvements.

At least there should soon be more skilled workers to install these heat pumps, fit solar panels and install insulation. The government’s recent announcement that it plans to train up to 18,000 skilled workers includes delivering up to 9,000 training places across England, with an extra £5 million to support 5,500 heat pump installers and 3,500 heat network professionals. It’s a good start, however, last year innovation charity Nesta suggested the industry would need about 37,000 heat pump installers by 2030, compared with about 3,000 currently trained, meaning up to 6,000 will need to be trained each year. Of course, many homeowners and landlords will want or need an energy assessment and/or EPC before investing in any of this equipment, but there was no mention of more training for Energy Assessors in the announcement. I guess that particular heated debate will have to wait for another time…