Staying warm without heating

Why heat is vital in winter: recognising hypothermia

The body keeps its core temperature around 37 degrees. If it cools below 35 degrees, it is hypothermia – a medical emergency. Unlike brief chilling, this is not about comfort but about circulation and consciousness.

Experts distinguish four stages and are guided by consciousness, not by shivering. With mild hypothermia (about 35 to 32 degrees) the person is awake and clear-headed and is usually shivering – shivering is the body's own heat production. With moderate hypothermia (below 32 down to 28 degrees) consciousness is clouded: the person becomes drowsy, confused and now responds only when spoken to. With severe hypothermia (below 28 degrees) they are unconscious but still breathing. If no signs of life can be detected any more, this is not a death sentence – resuscitate until the emergency services take over.

The most important warning sign is clouded consciousness: confusion, slurred speech, apathy and increasing drowsiness. Shivering cannot be relied on – it may be absent and is not a sign that the danger is over.

For beginners: do not wait until someone is «really cold». Act preventively – dress warmly, get out of the cold, warm drinks – before the first warning signs appear. Most at risk are children, elderly and sick people (see separate section).

Expert tip: remember the cascade of heat losses – then you set the right priorities. Through direct contact with cold ground, the body loses a lot of heat by conduction; through wet clothing by evaporation; through wind by convection. That is why an insulation mat under the body, dry clothing and a draught-free room often work better than an extra blanket on top.

1. With confusion, stopped shivering, clouded consciousness or unconsciousness: paramedics 144 (mountains/air rescue Rega 1414).
2. Protect from further cold: take to a warmer, wind-protected location, replace wet clothing with dry, wrap in blankets/sleeping bag and also insulate from the ground.
3. With moderate/severe hypothermia lie flat and still and move as little as possible – no jerky movements, no rubbing, no active warming of arms and legs, no alcohol (risk of heart rhythm disturbances / «rescue collapse»).
4. Only people who are awake and able to swallow: warm, sweetened drinks – never give anything to drink to anyone whose consciousness is clouded (choking risk).
5. Unconscious with normal breathing into the recovery position; with no normal breathing immediately resuscitate and 144.

How do I keep one room warm without heating?

Without heating, the most effective strategy is to keep one small room warm, not the whole flat. A small room with few people stays bearable considerably longer from body heat and warm clothing alone than a large, open flat. Choose an interior room with few outside walls and small windows; a bedroom often works well.

Then it is about keeping heat inside and cold outside. Close the doors to all other rooms and seal door gaps with rolled blankets or towels. Insulate windows at night with curtains, closed roller blinds or hung blankets – windows are the biggest heat leaks. All people stay together in this room: each body gives off heat, huddling together is worthwhile.

For beginners: think «tent in a room». A small dome tent or a canopy made of blankets over the bed shrinks the space to be heated further and keeps body heat closer to the body. This is especially effective at night.

Expert tip: use passive solar heat. Open curtains and roller blinds during the day on the sunny side and close them as soon as the sun is gone to retain captured heat. On the shaded side keep them closed all day. This gives you free heat without burning anything.

1. Choose small, interior room with few outside walls/small windows.
2. Close doors to all other rooms, seal door gaps with blankets/towels.
3. Insulate windows at night with curtains, roller blinds or blankets; sunny side open during day, then close again.
4. Gather all people in the same room – use body heat, huddle together.
5. Shrink the space further: tent, canopy of blankets or curtain around the bed nook.
6. Insulate from cold ground (sleeping mat, carpet, folded blankets) and stop draughts at floor level.

How do I keep my body warm without heating?

Against body cold, the layering principle works: several thin layers on top of each other warm better than one thick piece. Trapped air between the layers is the actual insulator. Another advantage: you can remove layers once you move and put them back on when sitting still.

Staying dry is crucial. Wet or sweaty clothing drains body heat many times more than dry because water conducts heat much better than air. Pure cotton directly on skin is poor in cold because it absorbs and holds moisture; wool or technical fibres keep some heat even when damp. Cover uncovered body parts – heat is lost over every bare surface, so hat, scarf, gloves and warm socks are worthwhile. (The common claim that you lose «most» heat through your head is a myth – see common mistakes.)

At night, a good sleeping bag and extra blankets are the most reliable heat source of all – without power and without exhaust. Always place an insulating layer under you (sleeping mat, carpet, folded blanket): without a base, cold ground pulls heat from the body no matter how thick the blanket on top. With a sleeping bag, the comfort temperature per standard is the key purchase value – not the extreme temperature, which marks only a survival limit.

For beginners: eat and drink warm when you can safely heat (outdoors) and eat enough – the body needs calories to produce heat. Move around regularly (stand, walk, squats): muscle work generates heat. Avoid heavy sweating though, because damp clothing cools you afterwards.

Expert tip: warm drinks warm mainly briefly and subjectively; real warmth comes from the calories in food. So rely on regular, energy-rich small meals instead of hot tea alone. A bottle filled with warm (not boiling) water, well sealed, in the sleeping bag gives off heat for hours.

1. Layering principle: several thin layers instead of one thick piece.
2. Stay dry: change wet/sweaty clothing; cotton not directly on skin.
3. Cover uncovered areas: hat, scarf, gloves, warm socks.
4. Sleep system: good sleeping bag (comfort temperature) plus blankets, always with sleeping mat underneath.
5. Movement in moderation: muscle work warms, but avoid heavy sweating.
6. Provide energy: eat enough, warm drinks – only for people who are awake.

⚠ Safe and dangerous heat sources: the carbon monoxide hazard

The single most dangerous mistake when staying warm is trying to heat indoors with an open flame or engine. Carbon monoxide (CO) forms in any combustion where there is too little oxygen – exactly when a barbecue, a patio heater, a gas heater or a generator burns in a closed room. The gas is colourless, odourless and tasteless; you cannot detect it with your senses and there is no natural warning.

In the body, CO displaces oxygen in the blood and attaches to red blood pigment much more strongly than oxygen. Organs suffocate internally, and a high concentration can cause unconsciousness and death within minutes. An ajar or even wide-open window is explicitly not protection – so it is absolute: charcoal and gas barbecues, patio heaters, gas heaters, petrol/paraffin cookers and power generators never belong in homes, basements or garages, not even «just briefly».

The first signs of CO poisoning are unspecific and easily misinterpreted: headache, nausea, dizziness, fatigue and light-headedness, later vomiting, shortness of breath and confusion to unconsciousness. An important warning sign is if multiple people in the same room become ill at once. If suspected: immediately everyone out into fresh air, do not stay indoors to ventilate, in severe cases paramedics 144, for advice poison control 145.

By contrast, measures that keep heat rather than burning it are safe: body heat, clothing, sleeping bag and blankets, a sealed small room and – if power from a charged power station is available – electric heat without exhaust. A permanently installed fireplace or wood stove is a real heat source, but only with correct operation: the chimney draught must be ensured, air supply must not be restricted too early, and the stove must never burn unattended – otherwise CO can also enter the living room.

For beginners: memorise one rule that prevents nearly all fatal accidents – nothing with flame, charcoal or engine burns indoors. Indoors, only heat that produces no exhaust counts.

Expert tip: if you heat with flame (fireplace, wood or paraffin stove), install a carbon monoxide detector per standard EN 50291. An ordinary smoke detector does not detect CO. The detector is the last safety net, but does not replace any behaviour rules. A paraffin or catalytic stove is – if at all – operated only with permanently open window gap, never in bedroom and never overnight.

Especially at risk: children, elderly and sick people

Cold does not affect everyone equally. Babies and small children cool faster than adults: they have a large body surface relative to weight, little insulating fat and immature temperature regulation – newborns can barely produce heat by shivering. Also, small children cannot reliably say they are cold.

Elderly are at risk for different reasons: their temperature regulation works less well, they shiver less, feel cold later, and certain medicines or illnesses can further impair heat balance. Also, chronically ill and bedbound people as well as those who move little are more affected because less muscle work means less heat production.

For beginners: regularly check if children, elderly and sick people have warm neck and torso (hands and nose may be cool). Dress them one layer warmer than yourself and actively plan warm drinks and movement because these people often do not react in time.

Expert tip: for at-risk people, first strengthen passive insulation and room shrinking rather than reaching for supplementary heaters. A warmly dressed child in the shared, sealed room with sleeping bag and mat is safer than with a risky substitute heater. Those dependent on power-driven medical devices should think through power failure beforehand with their own emergency power solution and the treatment team – see the guide for special groups.

1. Dress one layer warmer than healthy adults; hat and warm socks.
2. Check warmth where it counts: keep neck and torso warm (hands/nose may be cool).
3. Get them into the shared, warm room – never leave anyone alone in a cold room.
4. Regularly offer warm drinks and, where possible, gentle movement.
5. Watch for warning signs: apathy, drowsiness, stopped shivering – if in doubt 144.
6. Pre-secure power-driven medical devices / medicine refrigeration (emergency power, treatment team).

Common mistakes

1. Heating indoors with charcoal or gas barbecue, patio heater, gas heater or generator – even «just briefly» or with window open is deadly (carbon monoxide)
2. Relying on a window left ajar to protect from CO – it does not
3. Wanting to heat the whole flat instead of one small room sealed and kept warm
4. Using candles or a «tea light oven» with flower pot as room heating – heats barely and risks a candle wax fire with a sudden flare-up
5. Believing you lose «most» heat through your head – that is a myth; heat is lost over every uncovered surface, the hat is still worthwhile because the head is often the only uncovered spot
6. Thinking alcohol warms – it only widens skin blood vessels, feels warm briefly and actually increases heat loss; in cold it is dangerous
7. Lying under a blanket only but not insulating from cold ground – lots of heat is lost through the ground
8. Staying in wet or sweaty clothing – it cools the body
9. In advanced hypothermia, rubbing the person vigorously, jerky movement or actively warming – can trigger life-threatening heart rhythm disturbances (rescue collapse)
10. Leaving children, elderly or sick people alone in a cold room because they often notice cold too late

Frequently asked questions

Official sources

• Alertswiss (FOCP): Power outage Official preparedness recommendations
• Tox Info Suisse Poison control 145
• Guide: Survive power outages Basic preparedness without power
• Guide: Cooking & heating without power Cook safely, CO hazard in detail
• Guide: Emergency power & solar Electric heat from power station
• Guide: Build emergency supplies Cold-edible supplies & energy
• Guide: Special groups Children, elderly, sick, medical devices
• Scenario: Energy shortage Understand planned shutdowns
• Scenario: Gas leak Gas and CO hazards
• Emergency medicine: Hypothermia First aid for hypothermia