FrioSecção 03
Termómetro de interior
Why: para saberes se a casa está nos 18–21 °C recomendados no inverno — e qual é a divisão mais fresca no verão.
Essential guide · Base level · 8 min
Essential guideBase level · open to all8 min read
Extreme heat and cold: protecting your home and family
Heatwaves and cold spells: how to keep your home cool or warm safely, recognise heatstroke or hypothermia, and protect the most vulnerable.
Reviewed 1 Oct 2026
12·IA home protected from heat and cold
In 30 seconds
The essentials, in four points.
11–17 h
are the hottest hours. Stay in the shade or indoors, and spend at least 2 to 3 hours a day somewhere cool.
Water
Drink even when you're not thirsty, throughout the day. Avoid alcohol and caffeinated drinks on hot days.
18–21 °C
is the indoor temperature Portugal's health authority (DGS) recommends in winter. If you can't heat everything, heat the living room by day and the bedroom before bed.
0 braziers
Never use braziers, the hob or the oven to heat the house. Carbon monoxide kills with no smell and no warning.
01Why prepare
Extreme weather kills indoors, silently.
Heatwaves and cold spells don't cause visible damage like an earthquake or a flood, but they weigh heavily on health — especially for older people, babies, pregnant women, people with chronic illness and those who work outdoors. And it almost always happens at home: in houses too hot in summer and too cold in winter.
Portugal remains above the European average in the share of people who say they can't keep their home adequately warm, according to Eurostat. Many homes were built without insulation. The good news is that a lot can be done without building work or big expense.
Heatwave
Several days of very high temperatures in a row, with warm nights that don't let the body recover. Risk of dehydration and heatstroke.
Cold spell
Low temperatures for days, damp and poorly insulated homes. Risk of hypothermia and of poisoning from improvised heating.
No electricity
A blackout takes away the fan, the air conditioning and the heater. See the Blackout guide.
02Heat: keeping the house cool
By day, close. At night, air. Always, drink.
Step 1
By day, close
Shutters, blinds and outside shutters closed during sunny hours, especially on south- and west-facing windows. Heat that doesn't get in doesn't need getting out.
Step 2
At night, air
Open the windows when it's cooler outside than in — usually in the evening and early morning — and make a through-draught between opposite sides of the house.
Step 3
Drink and cool down
Water throughout the day, even without thirst. Cool showers or baths, loose light-coloured cotton clothes. Light meals.
1
Avoid the sun between 11:00 and 17:00. If you have to go out: wide-brimmed hat, sunglasses, sunscreen factor 30 or more, reapplied every 2 hours.
2
Spend 2 to 3 hours a day somewhere cool or air-conditioned: the coolest room at home, a library, a shopping centre. It gives the body time to recover.
3
Never leave anyone in a car in the sun: children, older people, sick people or animals. Not even for a few minutes, not even with the window open.
4
Babies under 6 months should not be in direct sun. Up to age 3, avoid direct exposure. Offer water or milk often.
5
Visit or call older people and those living alone at least once a day during a heatwave. Many don't feel thirsty.
6
Chronic illness or a fluid-restricted diet? Talk to your doctor or call SNS 24: 808 24 24 24 before changing how much water you drink.
Heat warning signs
What to do in each case1
Hot, dry skin, high temperature, fast pulse, confusion or fainting?
Yes
Heatstroke — call 112It is an emergency. While you wait: shade or a cool room, remove clothing, wet the skin and fan. Don't give drinks to anyone who isn't fully awake.
No
2
Intense thirst, heavy sweating, weakness, dizziness, nausea or cramps?
Yes
Heat exhaustionTake the person somewhere cool, lay them down, give water a little at a time and cool them. If they don't improve or get worse, call 112.
No
3
Painful cramps after effort in the heat?
Yes
Stop and restStop the activity, rest in the shade and drink water. Don't go back to exertion for the next few hours.
No
Keep watchingIf in doubt, call SNS 24: 808 24 24 24.
03Cold: keeping the house warm
Heat a small space, well — and without carbon monoxide.
1
18 to 21 °C at home. If you can't heat everything, concentrate heat in one room by day and warm the bedroom before bed. Close the doors of rooms you're not using.
2
Several layers of clothing instead of one very thick one. Protect your extremities: warm socks, gloves, hat and scarf. Avoid tight clothing.
3
Block the draughts around doors and windows with draught excluders or tape. Thick curtains closed at night and rugs on the floor help keep heat in.
4
Hot, frequent meals: soups and hot drinks. Alcohol makes you feel warm but makes you lose heat.
5
Fireplaces and wood stoves need a clean chimney and a well-ventilated room. Have the chimney swept before winter.
6
Electric heaters plugged straight into the wall, no extension leads or multi-plugs, and away from curtains, clothes and sofas.
7
Watch the most vulnerable: babies, older people, the chronically ill and those who live alone. Cold, like heat, can set in without the person noticing.
04Six costly mistakes
Heat and cold myths — and what to do instead.
Myth
“You drink when you're thirsty.”
In the heat, thirst comes late — in older people sometimes not at all. Drink water throughout the day, even without thirst.
Myth
“Opening the windows during the day cools the house.”
It lets hot air in. Close everything by day and air the house at night, when it's cooler outside.
Myth
“With the window open, the child can stay in the car for a bit.”
A car in the sun heats up very fast. Never leave anyone — or any animal — in a parked car in the sun.
Myth
“A shot of brandy warms you up.”
Alcohol widens the blood vessels in the skin and makes you lose heat. Choose soups and hot drinks.
Myth
“A brazier with the window ajar is safe.”
Carbon monoxide still builds up. The DGS is clear: never braziers for heating indoors.
Myth
“Heat and cold are only dangerous for the elderly.”
Babies, young children, pregnant women, the chronically ill and outdoor workers are also at risk.
05Recommended equipment
What measures, cools and heats safely.
What works best is free: shutters closed by day, windows open at night, layers of clothing and a single heated room. These items help — and a carbon monoxide detector is essential for anyone heating the home with a flame.
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CalorSecção 02
Ventoinha de pé
Why: dá conforto no calor moderado. Acima de cerca de 35 °C, prefere duches frescos e espaços climatizados.
FrioSecção 03
Manta de lã
Why: aquece sem gastar energia. Várias camadas finas aquecem mais do que uma só grossa.
FrioSecção 03
Detetor de monóxido de carbono
Why: indispensável com lareira, salamandra ou aquecedor a gás. Instala-o perto dos quartos.
Quick card
Print it. Stick it on the fridge.
Keep this sheet in sight, especially in older relatives' homes. On extreme days, it's the reminder that makes the difference.
Heat and cold · K72 sheet
1Heat: avoid the sun 11:00–17:00; shutters closed by day.
2Drink water even without thirst. No one left in a car in the sun.
3Heatstroke (hot dry skin, confusion): 112.
4Cold: home at 18–21 °C; layers; one heated room.
5Never braziers, hob or oven for heating.
6Health questions: SNS 24 — 808 24 24 24.
12·I · k72plus.comEMERGENCY: 112
- DGS — Heatwaves: recommendations for the public (in Portuguese) — 11–17 h, 2–3 h somewhere cool, cars, babies, warning signs
- DGS — Cold: general recommendations for the public (in Portuguese) — 18–21 °C, layers, braziers, hob and oven
- SNS 24 — Protect yourself from the heat (in Portuguese)
- CDC — Preventing heat-related illness — fans above ~35 °C
- CDC — Preventing hypothermia — signs of hypothermia in adults and babies
- Eurostat — Population unable to keep home adequately warm
Reviewed 1 Oct 2026 · Next review: Mar 2027 · Spotted a mistake? Tell us.
This guide does not replace medical advice. For serious symptoms, call 112; for health questions, call SNS 24: 808 24 24 24.
