Is air conditioning worth it for a UK business?

Does the law require air conditioning, or limit how hot a workplace can be?

No law sets a maximum workplace temperature. HSE says there is "no law for maximum working temperature, or when it's too hot to work, because every workplace is different". It adds that no meaningful upper limit can be imposed because in many indoor workplaces high temperatures "are not seasonal but created by work activity, for example in bakeries or foundries".

There is still a duty. Regulation 7 of the Workplace (Health, Safety and Welfare) Regulations 1992 says that "during working hours, the temperature in all workplaces inside buildings shall be reasonable". HSE tells employers to decide what is reasonable by assessing the risk and acting on the findings with controls "including temporary or seasonal ones". It also says heat "is classed as a hazard and comes with legal obligations like any other hazard". Air conditioning is one possible control, not a requirement. The workplace temperature law guide covers the duties in more detail.

When does cooling pay for itself?

Cooling pays when heat costs the business something it can name: equipment that fails, stock that spoils, a space people cannot work in. Test your own case against these situations.

Situation	Why cooling may be justified	A cheaper step to try first
Equipment-heavy rooms	Heat comes from the equipment, so the load does not stop in winter. HSE notes that high temperatures can be "created by work activity" rather than the season.	Check airflow and load before sizing anything; see server room cooling requirements.
Glazed or densely occupied offices	The Greater London Authority's London Plan lists "high proportions of glazing and an increase in the air tightness of buildings" among the design features that raise overheating risk.	HSE suggests blinds or reflective film on windows and moving workstations out of direct sun.
Stock that must stay cool	The Met Office says heat can affect "the transport of temperature-sensitive food and medicines".	Log actual temperatures through a hot spell, then decide whether the problem is the room or the stock.
Care homes, clinics and schools	The Climate Change Committee warns that "a large fraction of current buildings" are at risk of reaching uncomfortable and potentially dangerous temperatures in summer heatwaves.	Ventilation and shading first; see school ventilation and healthcare ventilation.

What should you try before buying air conditioning?

HSE's list of ways to help people who are too hot starts with simple measures. It includes desk, pedestal or ceiling-mounted fans, opening windows to keep air circulating, shading employees from direct sunlight with blinds or reflective film, positioning workstations away from sunlight or heat sources, and placing insulating materials around hot plant and pipes. Air-cooling or air-conditioning with adequate ventilation sits in the same list, which makes it one option among several.

Fans have limits. HSE says you "should not rely purely on desk or ceiling fans in poorly ventilated areas", but that if the workplace is adequately ventilated they can "help workers feel cooler". The London Plan applies the same logic as a cooling hierarchy that puts passive ventilation and mechanical ventilation before active cooling systems, and the guide to UK climate projections and cooling sets it out.

How do you estimate what it will cost to run?

Use a method rather than a rule of thumb, and keep every number traceable to your own building:

1. Estimate the cooling the building needs across the hot season, in kilowatt-hours, from the design load and a realistic number of operating hours.
2. Divide by the seasonal efficiency ratio (SEER) to get electricity used.
3. Add allowance for fans, pumps and standby. The formal SEER calculation includes the unit's standby, off-mode and crankcase-heater consumption.
4. Multiply by the unit rate on your own electricity bill.
5. Compare the result with the cost of the problem the cooling would solve.

Here is a hypothetical illustration, not a forecast. A small shop needs 6,000 kWh of cooling over a summer. At a SEER of 4.0 that is about 1,500 kWh of electricity, at 5.0 about 1,200 kWh and at 6.0 about 1,000 kWh. The saving between the first and last is about 500 kWh a year, and its value is that figure multiplied by your own unit rate.

Hours matter as much as efficiency. The ecodesign test table assumes cooling for 350 hours a year at full-load equivalent, so a room that must be cooled day and night will use far more electricity than a label implies. The air conditioning running costs guide and the office air conditioning cost examples work through pricing, and the commercial air conditioning cost guide covers what drives the purchase price.

How is air conditioning treated for tax?

For capital allowances, HMRC lists "air-conditioning and air cooling systems" among integral features. Integral features go into the special rate pool, which has a writing down rate of 6%. Companies can claim a 50% first-year allowance on special rate plant, not full expensing, which is for main rate plant. Special rate spending may also qualify for the annual investment allowance, which HMRC puts at £1 million. Whether a given system counts, and which relief fits, is a question for an accountant. The capital allowances guide goes further.

What does the climate add to the case?

The Met Office reports that summer 2026 was provisionally the warmest on record for the UK, with an average mean temperature of 16.5°C. The UK's official temperature record is 40.3°C, set at Coningsby, Lincolnshire, and verified in July 2022. The Climate Change Committee says increasingly hot summers "could lead to a trebling of health and productivity impacts without additional adaptation".

Those facts raise the stakes for buildings that already overheat. They do not decide the question for a single building: a north-facing office with good ventilation faces a different problem from a glazed one. The projections for each region are in will UK buildings need air conditioning.

A short checklist before you decide

1. Where does the heat come from, and when does it peak?
2. Which cheaper measures have been tried, priced or ruled out?
3. How many hours a year would the system run?
4. What are the seasonal efficiency and the unit rate?
5. Who benefits, whether staff, customers, stock or equipment, and does the building allow the plant?

Readers who have worked through these can send an enquiry through the site's form.

Sources

• HSE, Temperature in the workplace, What the law says and Managing workplace temperatures, checked 22 October 2026.
• HSE, Ventilation in the workplace: keeping a comfortable temperature, checked 22 October 2026.
• Legislation.gov.uk (Crown), The Workplace (Health, Safety and Welfare) Regulations 1992, regulation 7, checked 22 October 2026.
• Greater London Authority, The London Plan 2021, chapter 9, checked 22 October 2026.
• Climate Change Committee, Progress in adapting to climate change: 2025 report to Parliament (30 April 2025) and Risks to health, wellbeing and productivity from overheating in buildings, checked 22 October 2026.
• Met Office, Summer 2026 provisionally hottest on record for the UK, Record high temperatures verified and Deep Dive: What could UK summers feel like in the future?, checked 22 October 2026.
• Legislation.gov.uk (Crown), Commission Regulation (EU) No 206/2012, annex I and annex II, as retained in Great Britain, checked 22 October 2026.
• GOV.UK (HMRC), Rates and pools, Check if you can claim full expensing or 50% first year allowances, Annual investment allowance and Full expensing and 50% first-year allowance, checked 22 October 2026.

Common questions

Is it expensive to run air conditioning in the UK?

It depends on the hours it runs, the cooling load, the seasonal efficiency and the unit rate on your contract, so no single figure fits every building. Use the kilowatt-hour method above to size the electricity use, then price it at your own rate. The running costs guide covers the pricing step.

Is there a temperature at which staff can go home?

No. HSE says there is no law for when it is too hot to work, because every workplace differs. Employers must still keep the temperature reasonable, assess the risk and act on what they find.

Will fans be enough?

Sometimes. HSE says fans can help workers feel cooler where the workplace is adequately ventilated, but should not be relied on in poorly ventilated areas. If a room overheats because of equipment or sun through glass, the load may be larger than fans can handle.

Can a sole trader claim the same tax relief as a company?

Not all of it. HMRC says only companies can claim full expensing and the 50% first-year allowance. The annual investment allowance is £1 million for both sole traders or partnerships and limited companies, and an accountant can confirm which relief applies.

Related guides

• Cassette, ducted or wall-mounted air conditioning?
• How much does it cost to air condition an office? Three worked examples
• Split, multi-split or VRF: which commercial air conditioning?
• 2-pipe or 4-pipe fan coil systems?