UK homes are built to keep heat in, which is why a run of 30°C days is dangerous in a way it is not in Spain. The people who die are mostly over 65, often living alone, and often unaware they are in trouble. The UKHSA heat-health alert system gives days of warning. The rest is water, shade and knocking on doors.
Before
- Sign up for Met Office and UKHSA alerts
- Fit blinds or reflective film to south and west windows
- Check fridge and freezer are working; stock water and ice
- List the neighbours and relatives you will check on
- Ask the pharmacist about storing medicines in heat
- Plan for a power cut; they rise in heatwaves
During
- Windows and curtains shut on the sunny side by day; open at night
- Drink regularly; avoid alcohol and heavy meals in the heat of the day
- Stay out of the sun 11am to 3pm; shade, hat, suncream outdoors
- Cool showers, wet flannels on wrists and neck, feet in cold water
- Check on older or unwell people twice a day
- Never leave children or pets in a car
- Do not swim in open water to cool off: cold shock and currents kill
After
- Keep checking on vulnerable people for a day or two; effects lag
- Check medicines that were stored warm
- Restock water and note what helped
Keeping the house cool
Block the sun
Close curtains and blinds on any window in direct sun before it gets there, not after. External shading (awnings, shutters, even a sheet pegged outside) beats internal shading because it stops the heat before the glass. Reflective film on south-facing windows is cheap and permanent.
Ventilate at the right time
Keep windows shut while the outside is hotter than the inside, then open everything at night and early morning, upstairs and down, to pull cooler air through.
Turn things off
Ovens, tumble dryers, dishwashers, incandescent bulbs and big screens all heat a room. Cook early or eat cold food from the kit.
Use fans wisely
A fan cools you by moving air over your skin; it does not cool the room. Above about 35°C, a fan on dry skin can make things worse. Point it across a bowl of ice or use it with a damp flannel.
Move downstairs or to the coolest room
Heat rises. Sleep downstairs or in the north-facing room if the bedroom is unbearable.
Keeping people cool
Drink before you are thirsty: water, diluted squash, milk. Avoid alcohol and caffeine in the heat of the day. Cool the body directly: cool showers, feet in a bowl of cold water, wet cloths on the neck, wrists and ankles, a spray bottle. Loose, light clothing. Babies and small children need extra fluids and should never be in direct sun; older people often do not feel thirst and need reminding to drink.
Heat exhaustion: headache, dizziness, nausea, cramps, heavy sweating, fast pulse. Move them somewhere cool, lie them down, give water, cool the skin. They should improve within 30 minutes. If not, or if they become confused, stop sweating, have a fit or lose consciousness, that is heatstroke. Call 999 and keep cooling them while you wait.
Who to check on
The government's preparedness guidance asks you to plan to check on neighbours in an emergency, and a heatwave is the clearest case. Older people living alone, anyone with heart, lung or kidney conditions, people on certain medications, babies, and people with dementia or mobility problems. Knock twice a day. Is the house hot? Are they drinking? Are they confused or unusually sleepy? The neighbours guide has a simple way to organise this on a street.
Heat, power and water
Heatwaves strain the grid and the water network at the same time. Power cuts rise as equipment overheats; water pressure drops as demand doubles. Keep the power cut routine in mind, keep the fridge shut if the power fails, and have the bottled water in the kit. Hosepipe bans are a different matter: an inconvenience, not an emergency, but a sign the system is under stress.
Outdoors
- Hats, suncream, shade, and the heaviest activity before 11 or after 3.
- Never leave a child, an older person or a pet in a parked car, even for minutes; the interior can rise 10°C in ten minutes.
- Do not jump into rivers, reservoirs or the sea to cool down. Cold water shock and currents kill young, fit people every summer. Lifeguarded beaches only.
- Dry ground and hot wind mean wildfire risk. No barbecues or fires in the countryside, and cigarettes out properly.
Common questions
What are the heat-health alert levels?
The UK Health Security Agency issues yellow, amber and red heat-health alerts for England, alongside Met Office extreme heat warnings. Yellow means impacts for vulnerable people; amber means impacts across the health service and wider population; red means a risk to life for the general population. They are issued days ahead so you can plan.
What is the difference between heat exhaustion and heatstroke?
Heat exhaustion: headache, dizziness, nausea, heavy sweating, cramps, fast pulse. Move the person somewhere cool, give water, cool the skin with a wet cloth or fan; they should improve in 30 minutes. Heatstroke: confusion, no longer sweating, temperature over 40°C, seizures or loss of consciousness. Heatstroke is a medical emergency: call 999 and cool them while you wait.
Should I open the windows during the day?
Not while it is hotter outside than in, usually from late morning to early evening. Keep windows, curtains and blinds closed on the sunny side during the day and open everything at night and early morning to flush the house with cooler air. Light-coloured blinds or reflective film on south-facing glass make a big difference.
Why do heatwaves cause power cuts?
Demand for cooling rises, electrical equipment runs hot, and overhead lines sag and fault. Water demand also soars, so pressure drops and some areas lose supply. A heatwave is therefore also a reason to have the power cut and water parts of the kit in order.