Hospital wards reached a sweltering 35 degrees during the latest heatwave, the trust running Wexham Park Hospital has said – and its board has pledged to work to be better.

The NHS trust responsible for Wexham Park Hospital and Heatherwood Hospital is looking at ways to make older buildings more resilient against the heat.

NHS Frimley Health Foundation Trust has constructed a 2025-2028 ‘green plan’, which aims to upgrade its buildings to make them greener and better able to cope with extreme weather.

Its main aims include preparing for the effects of climate change, using more renewable energy and improving the way waste is managed.

The green plan also supports the trust’s goal of cutting its carbon emissions by 50 per cent over the next five years.

NHS Frimley trust’s board of directors discussed this at a meeting on Friday (July 3) at Frimley Park Hospital – which falls under the same trust.

One board member, Julia Gregory, said climate resilience – ie, the ability to prepare for, cope with and recover from the effects of climate change – is an area which ‘directly affects’ patients.

“It’s one thing being at home ill with a fan in your face but being in a hospital where you’ve got little control [is different],” she said.

James Clarke, chief strategy officer at Frimley Health NHS Foundation Trust, said temperatures in hospitals in the past few weeks have been ‘tough’ for patients and ‘not comfortable’.

There is no air conditioning in some buildings, and wards were reaching temperatures of 30 to 35 degrees Celsius during the heatwave, he said.

High temperatures are a risk to all sorts of vital hospital infrastructure, including systems which can overheat, fail or shut down.

During the extreme weather, the focus was on ensuring that operating theatres, IT server rooms, and systems that control the hospital environment could continue working.

Mr Clarke said: “There is a load of lessons that we’ve learned from [the heatwave] about how [to] make old buildings more resilient.

“You can’t just plug in loads of portable air conditioning units everywhere – which is what people like to do – because we just don’t have the power [or] resilience to be able to do that.”

In other words, the hospital’s existing infrastructure is not strong or flexible enough to cope with a sudden, large increase in demand from lots of portable air conditioning units.

Aside from building infrastructural resilience, the green plan involves other work, including removing piped nitrous oxide from the trust’s hospitals to reduce greenhouse gas emissions.

Nitrous oxide (often called ‘laughing gas’) is used for pain relief during childbirth and some operations.

However, it is a very powerful greenhouse gas, with a much greater warming effect than carbon dioxide, and the trust has concerns about wastage.

With piped nitrous oxide systems, gas can escape through leaks in the pipe network when it is not being used, creating waste.

The alternative to a piped system is usually a more targeted supply, perhaps using portable cylinders.

Frimley NHS trust’s plan is to work on removing the piped gas from its hospitals from July 2026 to May next year.

Meanwhile, 2,500 panels have been installed across the trust’s hospitals, generating ‘a significant amount of green energy’, said Mr Clarke.

But ‘roof issues’ at Wexham Park meant that ‘several panels could not be installed’, reducing the anticipated energy generation per year, a report said.

Waste management has also been a ‘big focus’, Mr Clarke said, and overall waste has been reduced.

Clinical waste reduced from 137.81 tonnes in January to 71.34 tonnes in June, a report said – a 48 per cent decrease.

Dry waste (such as packaging, not food waste or sewage-related) fell from 138 tonnes to 90 tonnes between January and June this year, it added.