Staying Cool Sustainably: Top Tips for Heatwaves in the Workplace

With UK summers getting hotter and more unpredictable, staying cool is no longer just about comfort. It is about safety, productivity and sustainability. By 2050, heatwaves are expected to happen every other year. Finding energy-efficient ways to keep your workplace comfortable is now essential for both your people and the planet.

It can be tempting to switch on the air conditioning, but this is one of the least energy-efficient ways to cool a space. Refrigerating all the air in a room consumes large amounts of energy, particularly in bigger areas with only a few people. Fortunately, there are many smarter, greener and more affordable ways to beat the heat.

Here is your iiE guide to keeping cool in a heatwave without blowing your carbon budget.

1. Understand Thermal Comfort

Thermal comfort is not just about the temperature reading on a thermostat. It is influenced by environmental factors such as:

• Air temperature

• Radiant temperature (warmth from surrounding surfaces, such as sunny windows)

• Airflow

• Humidity

Personal factors also play a role. Clothing, activity levels, and even body size and fitness can affect how hot or cold someone feels. In workplaces, it is impossible to please everyone, so aim to reduce the number of people feeling discomfort rather than focusing solely on the air temperature.

2. Reduce Heat Gains

Control sunlight and solar gain

• Use blinds and shades. Horizontal slats angled upwards can reflect heat away but still let in light. Thermal blinds can reflect heat out in summer and inwards in winter.

• Apply window films to reflect heat while keeping views and natural light.

• Install external shading such as pergolas, awnings or climbing plants to block high summer sun while allowing low winter sun.

Minimise other heat sources

• Improve insulation in roofs, walls and around hot water pipes. This helps keep heat out in summer and in during winter.

• Switch off appliances and lighting when not in use to reduce unnecessary heat gain.

• Upgrade to LED lighting, which uses less energy and produces less heat than incandescent or halogen bulbs.

3. Make the Most of Natural Ventilation and Air Movement

• Open windows and doors when outdoor temperatures are lower than inside.

• Close them and use blinds when it is hotter outside.

• Use fans to circulate air. Moving air is at least ten times more energy-efficient than air conditioning.

4. Use Air Conditioning Wisely

If air conditioning is needed:

• Turn off heaters in the same space.

• Set a “dead band” where no heating or cooling is used, ideally between 19°C and 24°C.

• Service units annually to prevent refrigerant leaks.

• Keep thermostats away from direct sunlight, heaters and draughts.

• Clean or replace filters regularly. Dirty filters can increase energy use by up to 15 percent.

5. Support Personal Cooling

Encourage staff to:

• Wear lighter, looser clothing where possible.

• Drink cool water regularly.

• Use desk fans or spray bottles for personal cooling.

Consider discussing cooling strategies in a team meeting or through your Green Team. Agree on dress code adjustments and preferred cooling methods during heatwaves.

6. Watch Water Consumption

Hot, dry weather can increase water use:

• Promote water-saving habits.

• Install rainwater harvesting systems for landscaping.

• Plant drought-resistant, bee-friendly plants and water them early in the morning to reduce evaporation.

7. Plan for the Future

• Generate your own energy with solar PV panels.

• Consider insulation, shading and ventilation improvements as long-term investments.

• Arrange a site audit to identify further savings and improvements.

Getting Started

1. Walk through your workplace to spot heat sources and problem areas.

2. Ask staff for feedback on when and where heat is an issue.

3. Put quick wins in place, such as shading and ventilation, before investing in bigger changes.

4. Contact your iiE advisor for tailored support.

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Keeping your workplace cool in summer does not have to mean higher bills or higher emissions. With smart planning, efficient equipment and a few low-cost changes, you can protect your staff, your bottom line and the environment.

Need help creating a sustainable cooling plan?
Email info@iie.uk.com or speak to your iiE advisor.