Summer is coming early. With the Met Office forecasting 2026 to be among the four hottest years on record and temperatures already climbing, some forecasters are warning of a heatwave pushing close to 30°C in early May.
2026 is currently forecast to fall in just behind 2024: recorded as the hottest year for the planet, at 1.55°C above the pre-industrial average. But some predictions show that global temperatures could rise as high as 1.58°C above the pre-industrial average this summer!
It is a pattern that has become all too familiar. Over the last five years, UK heatwaves have peaked at 36.4°C in 2020, 32.2°C in 2021, a roasting 40.3°C in 2022, 33.5°C in 2023 and 34.8°C in 2024, giving us (a country generally thought of as having a cold, windy and rainy climate) an average of 35.4°C of summer heat.
Of course, it’s impossible to give an exact prediction for when any 2026 heatwave might occur, although Claude AI offers: “The Met Office cannot predict heatwaves more than a few weeks in advance, so no forecast exists yet. However, based purely on historical pattern, late July 2026 would be the statistically most likely window — with mid-June to mid-August the broader risk period.” Our warming climate means this is the new normal. For the 44% of UK workers still making the daily commute to the office, it’s not just uncomfortable but bad for business too.
Rising office temperatures Research shows that more than 40% of employees already struggle to perform tasks when their workplace gets uncomfortably hot, costing the economy an estimated £1.2 billion in lost output every year.
With return-to-office pressure mounting, the stakes are higher than ever. Home workers can move to a cooler room, but office staff have no such luxury. If employers want people at their desks, keeping the temperature of the office bearable is the least they can do.
When a heatwave hits, instinct takes over, but instinct is usually wrong. Grabbing an ice cream on your lunch break feels sensible, but once your body breaks down the milk, fat and sugar, the heat generated by digestion can actually leave you warmer than before. And that cold shower after a sweaty commute? Cold water constricts the blood vessels in the skin, trapping heat inside your core rather than releasing it — a lukewarm shower does the job far better.
So, what actually works? A few smart changes can make a real difference. Here are some top tips for keeping your office cool when the temperature soars, with expert insights from Mike England, UK Rental Manager and HVAC expert at Daikin Rental Solutions.
1. Close your windows
Counterintuitive as it sounds, throwing every window open during a heatwave is one of the most common mistakes offices make.
“Keep windows closed and blinds drawn between 11am and 3pm, when outside temperatures peak,” Mike advises. “Open everything up early in the morning and again in the evening once the air outside has cooled. Office buildings hold heat through the day, so what you do first thing has a huge knock-on effect by mid-afternoon.”
Fitting reflective blinds or window film to south and west-facing glazing is one of the most affordable, high-impact upgrades you can make ahead of summer.
2. Switch off the lights
Most people overlook the fact that artificial lighting — especially older fluorescent and halogen fittings — generates a significant amount of heat. On a hot day, your office lighting could be quietly pushing the temperature up by several degrees.
LEDs produce a fraction of the heat of traditional bulbs and use less energy on top of that. It is one of those changes that pays for itself quickly and makes a noticeable difference to how warm a room feels. Incandescent bulbs release around 90% of their energy as heat, while LEDs convert around 90% into light, with only 10% wasted as heat. A University of Michigan study also found that LED lighting is up to 44% more efficient than fluorescent tubes, making the switch one of the simplest and most cost-effective steps an office can take.
3. Ditch the desk fans
“Fans move air around, but they don’t actually lower the temperature of a room,” says Mike. “In a packed office, you can end up just circulating warm air around, which can make it more uncomfortable for everyone, rather than cool.” For buildings without a permanent air conditioning system, hiring a portable air cooler is a far more effective solution. Rental is a smart option for businesses that only need serious cooling for a few weeks each year. You get the right equipment scaled to your space, without a major capital outlay.
4. Turn off unnecessary tech
Computers, monitors, printers and servers all generate heat and most offices have far more equipment switched on than they need at any given time. According to research, plug loads from office equipment account for between 20% and 50% of a building’s total energy use, making them a significant but easily overlooked contributor to indoor temperature.
Encouraging staff to switch off monitors, printers and any equipment they are not actively using is a surprisingly effective way to reduce ambient temperature. “Server rooms are often the single biggest heat source in an office building and are worth addressing separately with proper cooling, rather than letting that heat bleed out into the rest of the space,” Mike recommends.
5. Rearrange the office
Proximity to sun-facing windows can make an enormous difference to how hot an individual feels throughout the day, yet most offices never think to account for this in their layout.
If you have staff sitting directly in the path of afternoon sun through west-facing windows, they are going to be significantly hotter than colleagues a few metres away: obvious when you think about it!
Something as simple as rearranging desks away from the worst-affected glazing, or creating a cool-zone in a shadier part of the building, can make a big difference without spending a penny.
6. Plan now, not later
“The biggest mistake is leaving it too late,” says Mike. “Check your building now, identify the problem areas and have a plan in place before temperatures spike. The offices that cope best in a heatwave are rarely the ones with the best equipment — they are the ones that prepared early.” The Grantham Institute supports Mike’s point, with findings showing organisations are usually underprepared for periods of extreme heat. The businesses that handle high temperatures best are the ones that treat it like any other operational risk and prepare for it early.
With a record-breaking summer on the cards, there has never been a better time to get ahead of the heat. A few smart changes now could make all the difference when the temperature spikes.
How to Survive a Heatwave in the Office – With 2026 Forecast to be Among Hottest Years on Record!
Summer is coming early. With the Met Office forecasting 2026 to be among the four hottest years on record and temperatures already climbing, some forecasters are warning of a heatwave pushing close to 30°C in early May.
2026 is currently forecast to fall in just behind 2024: recorded as the hottest year for the planet, at 1.55°C above the pre-industrial average. But some predictions show that global temperatures could rise as high as 1.58°C above the pre-industrial average this summer!
It is a pattern that has become all too familiar. Over the last five years, UK heatwaves have peaked at 36.4°C in 2020, 32.2°C in 2021, a roasting 40.3°C in 2022, 33.5°C in 2023 and 34.8°C in 2024, giving us (a country generally thought of as having a cold, windy and rainy climate) an average of 35.4°C of summer heat.
Of course, it’s impossible to give an exact prediction for when any 2026 heatwave might occur, although Claude AI offers: “The Met Office cannot predict heatwaves more than a few weeks in advance, so no forecast exists yet. However, based purely on historical pattern, late July 2026 would be the statistically most likely window — with mid-June to mid-August the broader risk period.” Our warming climate means this is the new normal. For the 44% of UK workers still making the daily commute to the office, it’s not just uncomfortable but bad for business too.
Rising office temperatures Research shows that more than 40% of employees already struggle to perform tasks when their workplace gets uncomfortably hot, costing the economy an estimated £1.2 billion in lost output every year.
With return-to-office pressure mounting, the stakes are higher than ever. Home workers can move to a cooler room, but office staff have no such luxury. If employers want people at their desks, keeping the temperature of the office bearable is the least they can do.
When a heatwave hits, instinct takes over, but instinct is usually wrong. Grabbing an ice cream on your lunch break feels sensible, but once your body breaks down the milk, fat and sugar, the heat generated by digestion can actually leave you warmer than before. And that cold shower after a sweaty commute? Cold water constricts the blood vessels in the skin, trapping heat inside your core rather than releasing it — a lukewarm shower does the job far better.
So, what actually works? A few smart changes can make a real difference. Here are some top tips for keeping your office cool when the temperature soars, with expert insights from Mike England, UK Rental Manager and HVAC expert at Daikin Rental Solutions.
1. Close your windows
Counterintuitive as it sounds, throwing every window open during a heatwave is one of the most common mistakes offices make.
“Keep windows closed and blinds drawn between 11am and 3pm, when outside temperatures peak,” Mike advises. “Open everything up early in the morning and again in the evening once the air outside has cooled. Office buildings hold heat through the day, so what you do first thing has a huge knock-on effect by mid-afternoon.”
Fitting reflective blinds or window film to south and west-facing glazing is one of the most affordable, high-impact upgrades you can make ahead of summer.
2. Switch off the lights
Most people overlook the fact that artificial lighting — especially older fluorescent and halogen fittings — generates a significant amount of heat. On a hot day, your office lighting could be quietly pushing the temperature up by several degrees.
LEDs produce a fraction of the heat of traditional bulbs and use less energy on top of that. It is one of those changes that pays for itself quickly and makes a noticeable difference to how warm a room feels. Incandescent bulbs release around 90% of their energy as heat, while LEDs convert around 90% into light, with only 10% wasted as heat. A University of Michigan study also found that LED lighting is up to 44% more efficient than fluorescent tubes, making the switch one of the simplest and most cost-effective steps an office can take.
3. Ditch the desk fans
“Fans move air around, but they don’t actually lower the temperature of a room,” says Mike. “In a packed office, you can end up just circulating warm air around, which can make it more uncomfortable for everyone, rather than cool.” For buildings without a permanent air conditioning system, hiring a portable air cooler is a far more effective solution. Rental is a smart option for businesses that only need serious cooling for a few weeks each year. You get the right equipment scaled to your space, without a major capital outlay.
4. Turn off unnecessary tech
Computers, monitors, printers and servers all generate heat and most offices have far more equipment switched on than they need at any given time. According to research, plug loads from office equipment account for between 20% and 50% of a building’s total energy use, making them a significant but easily overlooked contributor to indoor temperature.
Encouraging staff to switch off monitors, printers and any equipment they are not actively using is a surprisingly effective way to reduce ambient temperature. “Server rooms are often the single biggest heat source in an office building and are worth addressing separately with proper cooling, rather than letting that heat bleed out into the rest of the space,” Mike recommends.
5. Rearrange the office
Proximity to sun-facing windows can make an enormous difference to how hot an individual feels throughout the day, yet most offices never think to account for this in their layout.
If you have staff sitting directly in the path of afternoon sun through west-facing windows, they are going to be significantly hotter than colleagues a few metres away: obvious when you think about it!
Something as simple as rearranging desks away from the worst-affected glazing, or creating a cool-zone in a shadier part of the building, can make a big difference without spending a penny.
6. Plan now, not later
“The biggest mistake is leaving it too late,” says Mike. “Check your building now, identify the problem areas and have a plan in place before temperatures spike. The offices that cope best in a heatwave are rarely the ones with the best equipment — they are the ones that prepared early.” The Grantham Institute supports Mike’s point, with findings showing organisations are usually underprepared for periods of extreme heat. The businesses that handle high temperatures best are the ones that treat it like any other operational risk and prepare for it early.
With a record-breaking summer on the cards, there has never been a better time to get ahead of the heat. A few smart changes now could make all the difference when the temperature spikes.
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