The annual tradition of not being prepared for Summer
The typical British summer is not the kind of thing you’d expect to put in your risk assessment or budget forecast, and yet every year as soon as the sun makes an appearance, the same issue starts creeping into workplaces across the UK; rooms that are too hot to inhabit by lunchtime.
If you work in a building with large panes of glass - or even just your standard office windows - then you probably know the feeling.
At best, it's a bit stuffy, but at worst, it’s oppressive*.
It happens every year, and it's become something of a British tradition.
But what if it didn’t have to be?
The impact of overheating on productivity
According to the Chartered Institution of Building Services Engineers (CIBSE), once indoor temperatures reach 25°C, performance is more likely to be affected ¹.
It’s measurable: reduced concentration, slower cognitive function, more complaints and lower productivity, on top of the fact that you have an unhappy team on your hands, which is bad enough in itself.
In many modern buildings, and especially those that have south-facing windows, 25°C is reached long before lunchtime on an ordinary summer's day.
You don’t actually need a heatwave; you just need sun
In an experimental study published in Solar Energy (2024), researchers found that applying solar control film to a glazed surface reduced indoor air temperature by up to 4°C ².
That might not sound dramatic written down, but in the real world, it’s the difference between a meeting room sitting at 26°C and one that holds at a manageable 22°C.
Between "let’s move this meeting elsewhere" and "why didn’t we do this sooner?"
It's the difference between bearable and unbearable.
What about blinds?
It’s not actually just the air temperature that makes things unbearable. Solar gain is the process in which sunlight passes through glass and heats the interior and is one of the biggest contributors to overheating in glass-heavy buildings.
Traditional fixes like blinds or curtains only reduce visible light; they don’t prevent heat from entering the space, they often just trap it inside.
Plus you can risk blocking out natural light completely, leaving staff working in artificial darkness in summer just to avoid overheating.
The real solution is stopping the heat at the source before it passes through the glass.
Film is a passive solution with a real impact
Solar control window film is designed to do what it says on the tin; it reflects and absorbs solar energy, preventing up to 80% of solar heat from entering the building.
It also cuts glare and blocks 99% of UV rays (the harmful ones) protecting office equipment, flooring and your interior from long-term damage.
Once applied, it doesn’t require adjusting, special cleaning, opening, closing or managing: it simply works silently and effectively in the background.
There doesn't need to be disruption to daily operations during installation, no need for expensive structural changes, and no ongoing energy consumption costs like that of air conditioning.
It's a single, passive intervention that instantly improves the usability of a space.
Image: A view from the inside of an office with a recent install, with no light or love lost.
Case in point
At Hillsborough Football Stadium we've recently finished installing a grey external window film to 99 windows in their control room and private boxes.
As much as the boxes do look so much better now than before, this wasn't the real issue. The issue was the temperatures which were reached in the control room in the middle of summer: not pleasant at the best of times, but when you're on duty focussing on keeping 34,000 people safe? That's a different story.
Within two days and without any downtime for the club, the building had a consistent appearance, drastically reduced glare, and more crucially, a more comfortable temperature for staff to work in.
You can read the full case study here.
A small change can make a big difference
For businesses the cost of lost productivity is rarely tracked in degrees, but it’s felt in small, subtle ways every summer.
Staff lose energy, teams shift to more tolerable corners of the building. Customers cut visits short. People get frustrated and focus is lost.
Window film isn’t flashy or sexy and it won't make the front cover of The Times anytime soon, but for many workplaces, it’s the simplest and most cost-effective improvement they’ll make all year.
Want to learn more or speak to someone about your building?
We offer free surveys and honest advice and NEVER make any pushy sales calls.
Our solution speaks for itself.
📞 01482 654654
📧 dom@glasstint.co.uk
*Hot working temperatures are considered oppressive when they create physical and mental discomfort that can interfere with a person’s ability to concentrate, make decisions, and perform tasks effectively.
¹Based on indoor temperature thresholds outlined in CIBSE Guide A: Environmental Design (2006) www.cibse.org
²Download the study here via ScienceDirect