TL;DR
Heatwave conditions raise three household cost questions: how much extra electricity cooling will use, what home and contents insurance covers, and what workers can expect from employers. The UKHSA has placed amber heat-health alerts across much of southern England.
Last reviewed 3 June 2026
Key facts
- UKHSA amber heat-health alerts have been issued across South West, South East, London, East and West Midlands, and East England regions.
- A standard 3kW portable air conditioner running for 8 hours uses around 24 kWh, costing roughly £6.50 to £7 at the April 2026 capped electricity unit rate.
- ABI buildings insurance data show subsidence and sun damage claims rise during prolonged heatwaves.
- The Workplace (Health, Safety and Welfare) Regulations 1992 require employers to provide a reasonable working temperature but set no statutory upper limit.
- The Met Office three-month summer 2026 forecast signals increased heatwave likelihood through June, July and August.
Cooling and the electricity bill
Domestic cooling in the UK relies mostly on fans and portable air conditioning units. Fan running costs are modest. A standard pedestal fan rated at 50 watts costs around 1.4 pence per hour at the April 2026 Ofgem capped electricity unit rate of around 27p per kWh. Eight hours of overnight use costs roughly 11p.
Portable air conditioning is significantly more expensive. A 3kW unit running for 8 hours uses around 24 kWh, costing roughly £6.50 to £7 at the same unit rate. Households using portable AC every day during a two-week heatwave can add £90 or more to a monthly electricity bill.
Reflective window film, blackout curtains and natural night cooling are no-cost interventions that reduce indoor temperatures by several degrees and cut cooling demand.
What home insurance covers in heatwaves
Standard buildings and contents policies typically cover three heat-related risks. Subsidence: Prolonged dry conditions cause clay soils to shrink, which can damage foundations. Buildings insurance covers subsidence but excesses are usually high, often £1,000 or more.
Sun damage to interior contents: Most contents policies cover sudden damage but not gradual fading. A south-facing room with prolonged direct sun is unlikely to trigger a claim for faded upholstery.
Garden fires: Buildings insurance usually covers fires that spread to the property, but the source of ignition matters. Discarded barbecue coals are typically covered; arson by a third party requires a police reference.
The Association of British Insurers publishes annual claims data showing heatwave summers correlate with elevated subsidence claim activity over the following 12 to 18 months.
Working in the heat: what employers must do
The Workplace (Health, Safety and Welfare) Regulations 1992 require employers to maintain a reasonable temperature inside workplaces and provide clean, fresh air. There is no statutory upper temperature limit in UK law. The Health and Safety Executive (HSE) guidance suggests employers carry out a thermal comfort risk assessment when staff complain of heat stress.
Outdoor workers fall under the same duty-of-care principles. Employers should provide shade, water, rest breaks, and consider rescheduling heavy work to cooler parts of the day. Failing to assess risk can expose employers to claims for personal injury from heat stroke.
Advisory: If symptoms of heat exhaustion or heat stroke appear (severe headache, confusion, fainting, temperature above 40°C), call 999. Vulnerable groups including older adults, infants and people with cardiovascular conditions face elevated risk.
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Disclaimer
This article is for general information only and does not constitute financial, legal, tax, insurance, or investment advice. Kael Tripton Ltd is registered with the Information Commissioner's Office (ICO ZC135439) as a data controller but is not authorised by the Financial Conduct Authority. Figures and rules are correct at time of publication and may change. Always check the primary source linked below before acting on any information, and seek advice from a qualified professional for your specific circumstances.
Sources
Frequently asked questions
Is there a legal maximum workplace temperature in the UK?
No. The Workplace (Health, Safety and Welfare) Regulations 1992 require a reasonable temperature but set no upper statutory limit. HSE guidance recommends a thermal comfort risk assessment when complaints arise.
How much extra does it cost to run a portable air conditioner?
A 3kW portable AC running for 8 hours uses around 24 kWh. At the April 2026 Ofgem capped electricity rate of around 27p per kWh that costs roughly £6.50 to £7 per day.
Does home insurance cover damage caused by a heatwave?
Buildings insurance typically covers subsidence following prolonged dry weather, subject to a high excess. Contents insurance covers sudden damage but generally excludes gradual sun fading. Check policy wording before relying on cover.
Can I take time off work because of the heat?
There is no automatic statutory right to time off due to heat. If the workplace temperature creates a health and safety risk, raise the issue with the employer and HSE. Vulnerable employees may have additional rights under the Equality Act 2010.
