How do I keep a vulnerable person safe in a heatwave?

Older people, young children and anyone with a heart, lung or kidney condition overheat faster and notice it later. The job is to keep one room genuinely cool and to check on them often enough to catch it early.

Difficulty: beginner
Time: 30 min
Read: 6 min
Safety: warning

Short answer

Keep one room cool and use it: windows and curtains shut through the day, opened wide once the outside air is cooler than the inside. Offer drinks far more often than they ask — thirst is unreliable in older people. Check on them at least twice a day in hot weather, and know the difference between heat exhaustion, which cooling fixes, and heatstroke, which is a 999 call.

The people most at risk in a UK heatwave are over 75, living alone, in a top-floor or south-facing flat, on medication such as diuretics, beta blockers or antipsychotics, or with dementia. Several of those things blunt the body's response: thirst diminishes with age, some medicines reduce sweating or fluid retention, and someone with dementia may not connect feeling unwell with taking off a jumper or having a drink. Heat deaths in the UK are overwhelmingly in this group and overwhelmingly indoors.

Safety

Heatstroke is a medical emergency. Ring 999 if someone is confused, unresponsive, has stopped sweating, has hot dry skin, is having a seizure or has a very high temperature. While waiting, move them somewhere cool, remove outer clothing, and cool them with cold wet cloths or sponging and a fan. Do not give anything to drink if they are drowsy or confused. Heat exhaustion that has not improved after 30 minutes of cooling is treated as heatstroke.

What you'll need

A room that can be kept cool — usually north-facing or ground floor
A fan
A room thermometer (optional)
Cold drinks and ice
A phone number for a neighbour, family member or carer
Light cotton bedding and clothing (optional)

Which windows to shade and when to open them

Step by step

Pick one room and make it the cool room.Usually north-facing, ground floor, and not the one with the biggest window. Everything else follows from committing to one space rather than trying to cool the whole house.
Close windows and curtains before the day heats up, not after.Once the outside air is warmer than the inside, an open window is bringing heat in. Shut up by mid-morning, and shade the glass — external shading blocks far more than any internal curtain.
Open everything up once the outside air is cooler.Usually late evening in the UK. Open windows on two different sides or at two different heights so air actually moves through, and put a fan in an upstairs window blowing outwards to pull the day's heat out.
Offer drinks on a schedule rather than waiting to be asked.Every hour or two, whether they say they are thirsty or not. Water, squash, milk, tea — anything except large amounts of alcohol. Ice lollies and fruit work for someone who will not drink.
Use cool water on skin rather than trying to cool the whole person.A cool damp flannel on the neck, wrists and forearms, a cool shower, or feet in a bowl of cool water. It works quickly, it is comfortable, and it does not require the room to be cold.
Be careful with fans above about 35 degrees.A fan in very hot air blows hot air over the skin and can increase dehydration, especially in older people. Below that, a fan helps; above it, cooling the skin with water matters more.
Check medicines and storage.Some medicines increase heat risk and some spoil above 25 degrees. Keep medicines out of hot rooms and conservatories, and ask a pharmacist rather than stopping anything — never adjust a prescribed dose because of the weather.
Move activity to the cool part of the day.Shopping, gardening, walking the dog, appointments if they can be moved — before 11 in the morning or after 6 in the evening. Between 11 and 3 is the part of the day to spend indoors.
Agree who checks in, and how often.At least twice a day in a heat alert, by someone who will actually go round rather than ring. Confusion is one of the first signs of trouble and it does not come across on the phone.
Know the two levels and act on the difference.Heat exhaustion — tired, dizzy, headache, sweating heavily, cramps — responds to a cool place, cool water on the skin and fluids within 30 minutes. Heatstroke — confusion, hot dry skin, no sweating, unresponsive — is 999, immediately.

Tips

Sign up to the Priority Services Register with the energy and water suppliers. It is free, and it gets priority support and advance warning if supplies are interrupted during a heat alert.
A cool damp sheet over a bed, with a fan moving air across it, makes an unbearable bedroom sleepable without any cooling equipment.
Watch for someone who stops going to the toilet or whose urine is dark — dehydration in older people shows there long before it shows anywhere else.
Heat alerts from the UK Health Security Agency are issued by region and are worth signing up for on behalf of someone you care for.
In a flat with no cross-ventilation, the cool room may have to be the bathroom or hallway. A cool floor to sit on is worth more than a hot room with a view.

Common mistakes

Leaving windows open all day because it feels stuffy — Above about 22 degrees outside, an open window is a heater. The house fills with hot air by lunchtime and then cannot be cooled that evening.
Assuming someone will say if they are too hot — Thirst and heat perception both decline with age, and dementia removes the link entirely. Someone can be dangerously overheated while insisting they are fine.
Treating heatstroke as bad heat exhaustion — Confusion, hot dry skin and no sweating mean the body has stopped regulating. That is a 999 call and cooling starts while you wait, not after a wait-and-see.
Pushing large amounts of water on someone with heart or kidney problems — Some conditions restrict fluid intake. Offer regular small drinks and, where there is a fluid restriction, follow the medical advice rather than a general rule.

If it doesn't work

The flat never cools down, even at night

Cause: Thermal mass that has absorbed heat all day, plus no cross-ventilation — Fix: Start the shutting-up earlier each morning, shade the glass from outside, and open windows on two sides or at two heights overnight. A fan in a window blowing out beats a fan pointed at a chair.

They will not drink

Cause: Reduced thirst, or difficulty with cups — Fix: Change the format rather than pushing the same drink — ice lollies, jelly, melon, cucumber, soup, milky drinks. A lidded beaker or a straw solves more refusals than persuasion does.

Confused and drowsy in the afternoon

Cause: Possible heatstroke — Fix: Ring 999. Move them somewhere cool, remove outer clothing, cool the skin with water and a fan, and do not give drinks while they are drowsy.

Questions people ask

What temperature is too hot indoors?

There is no single legal figure, but above about 26 degrees indoors is where risk starts rising for older and unwell people, and medicines should generally not be stored above 25. A cheap room thermometer in the cool room is worth having so the decision is not a guess.

Is a portable air conditioner worth it?

For someone genuinely at risk, yes — but only the type with a hose vented out of a window, and the window gap must be sealed round the hose or it undoes itself. A unit with no hose is a humidifier that makes a hot room worse.

What if they live alone and refuse help?

Agree the smallest thing they will accept — a daily phone call at a fixed time, a neighbour with a key, a cool room set up once at the start of the week. Adult social care at the council can also do a welfare check if you are genuinely worried and cannot get an answer.