Staying Warm Without Heat

During the February 2021 Texas freeze, over 4.5 million homes lost heating as the power grid failed in temperatures that reached −18°C in some areas. Dozens of people died from hypothermia — not outdoors, but inside their own homes. Cold homes kill quietly and progressively: judgement impairs, movement slows, and the person becomes increasingly unable to recognise or respond to their own deteriorating condition. The key insight from events like this is that passive warmth management — knowing how to retain body heat with what you have — is as lifesaving as any active heating system.

Understanding Cold and Hypothermia

The Heat Loss Equation

The body generates heat through metabolism and muscular activity, and loses it through five mechanisms:

• Radiation — heat radiating from skin into the surrounding air
• Conduction — heat transferring to cold surfaces in direct contact
• Convection — cold air moving over skin and removing heat
• Evaporation — moisture (sweat, wet clothing) drawing heat away as it evaporates
• Respiration — warm exhaled air replacing cold inhaled air

Effective warmth retention addresses all five. Dry, still, insulated environments are warm. Wet, moving, uninsulated environments kill.

Hypothermia Progression

Stage	Core Temperature	Signs	Action Needed
Mild (35–37°C)	95–98.6°F	Shivering, goosebumps, clumsy	Add insulation, warm drinks, movement
Moderate (32–35°C)	89–95°F	Intense shivering, confusion, slow movement	Insulate, remove wet clothes, warm core
Severe (<32°C)	<89°F	No shivering, severe confusion, drowsiness	Emergency — active rewarming, medical care
Critical (<28°C)	<82°F	Unconsciousness, apparent death	Emergency — handle gently, do not rub, CPR if needed

⚠️ Paradoxical undressing — removing clothing as hypothermia progresses — occurs because the dying capillaries near the skin suddenly dilate, creating a false sensation of warmth. If someone begins removing clothes in a cold environment, treat as severe hypothermia immediately.

Shivering is helpful: It is the body's muscular heat generation mechanism. When shivering stops, it means either the body has warmed or it has exhausted its ability to generate heat — and the latter is life-threatening.

Layering System — The Warmth Foundation

The most effective warmth strategy requires no heat source — just correct clothing layering.

The Three-Layer System

Base layer — moisture management

• Purpose: wick moisture away from skin (sweat in wet clothing rapidly conducts heat away from the body).
• Materials: merino wool, polypropylene, or other synthetic wicking fabrics.
• NOT cotton — "cotton kills" is a valid survival principle. Wet cotton loses nearly all its insulating value and stays wet.

Mid layer — insulation

• Purpose: trap warm air close to the body.
• Materials: fleece, down, or synthetic fill (Thinsulate, PrimaLoft).
• Down is the warmest per weight when dry; synthetic fill retains insulation when wet. For emergency preparedness, synthetic is more versatile.

Outer layer — wind and moisture barrier

• Purpose: prevent wind from penetrating the insulating layer; shed rain or snow.
• Materials: waterproof-breathable fabrics (Gore-Tex, eVent) or polyurethane-coated nylon.
• Without a wind barrier, even a thick fleece loses most of its insulating value in a breeze.

Critical Zones

• Head: 20–40% of heat loss from the body occurs through the head in cold environments. A hat is not optional.
• Neck: A buff or scarf traps a significant amount of warm air.
• Hands: Mittens are warmer than gloves (fingers share warmth); liners under mittens add layers.
• Feet: Double socks (wicking liner + wool outer) and waterproof boots.

Insulating Your Home

When central heating fails, the goal is to reduce the size of the space you are trying to keep warm and increase its insulation.

Concentrate in One Room

Choose the smallest, most insulated room — preferably interior (surrounded by other rooms on multiple sides, not against exterior walls). The smaller the space and the more bodies in it, the faster it warms with body heat alone.

1. Move sleeping gear, supplies, and warm clothing into this room.
2. Seal the door: Roll towels, stuff blankets, or tape foam along the gap at the bottom and sides of the door.
3. Cover windows: Thermal curtains, blankets, or taped bubble wrap on windows significantly reduces heat loss through glass. A double layer of plastic sheeting taped over the window frame (with an air gap) creates an improvised double-glazing effect.
4. Block draughts: Feel around window frames, electrical sockets, and any gaps in the floor for cold air infiltration. Seal with tape, blu-tack, or stuffed cloth.

Internal Tent or Blanket Shelter

Inside a room, a further layer of insulation can be created:

• Hang blankets from the ceiling, over furniture, or between chairs to create a smaller enclosed space.
• A tent pitched indoors concentrates body heat effectively.
• "Blanket forts" are a legitimate emergency warmth strategy, not just for children.

Emergency Heating Options

Safe Options

Electric space heaters — if electricity is available (including from a generator outdoors). Oil-filled radiators are the safest option: no exposed element, no fire risk, slow and steady heat output.

Indoor-rated propane heater (e.g., Mr. Heater Buddy) — specifically rated for indoor use, these have oxygen depletion sensors that shut them off if CO rises.

• Still requires minimal ventilation: crack a window slightly.
• Install a CO detector before using.
• Never sleep with one running.
• Run time: approximately 3–6 hours per 1 lb (450g) propane cylinder.

Indoor-rated kerosene heater — similar considerations to propane. Requires kerosene (1-K grade) stored safely. Provides good heat output for a room.

Wood-burning stove or fireplace — the gold standard. Burns sustainably sourced wood with no fuel shortage risk. Requires a properly installed and swept chimney.

Unsafe Options — What Never to Do

Device	Why It Kills
Barbecue grill (indoors)	Produces massive amounts of CO; has killed people within minutes
Charcoal grill or briquettes (indoors)	CO is produced even when fully burning; charcoal is particularly dangerous indoors
Outdoor propane heater (patio heater)	Not rated or designed for enclosed spaces; CO accumulation
Gas oven or range for space heating	CO production; fire risk from items placed near burners
Running vehicle engine in garage	CO poisoning; has killed numerous people even with doors open

⚠️ Carbon monoxide is colourless, odourless, and tasteless. You will not detect it until you are already cognitively impaired. A CO detector is not optional when using any combustion heating. Keep fresh batteries installed.

Sleeping Warm

Body temperature drops during sleep — planning for warm sleep in a cold house is critical.

Sleeping Bag Strategy

A sleeping bag rated to the ambient temperature is the single most effective piece of equipment for sleeping warm without heating. Temperature ratings:

• Season 1 (comfort 12°C+): Summer camping — not useful in an unheated home in winter
• Season 3 (comfort 0–5°C): Good general purpose; adequate for most unheated homes in temperate climates
• Season 4 (comfort −10°C): For severe cold; ideal emergency purchase for cold climates

Hot water bottle — fill from any heat source (camping stove, fireplace) and place inside the sleeping bag 15–20 minutes before getting in. Maintains warmth for 4–6 hours.

Other Sleeping Strategies

• Layer clothing in bed — wear full insulating layers to sleep.
• Hat in bed — significant warmth contribution.
• Multiple people sharing sleeping space (and sleeping bag warmth) is effective.
• Mylar emergency blankets — reflect body heat back; use inside a sleeping bag or as an additional outer wrap.
• Keep face inside the sleeping bag when cold — body heat warms the air within the bag.

Protecting Vulnerable People

Elderly Individuals

Cold is particularly dangerous for the elderly:

• Metabolism slows with age, reducing heat generation.
• Circulation to extremities is reduced.
• Temperature perception may be impaired — elderly people may not feel cold even when at risk.
• Many medications affect temperature regulation.

Check on elderly household members and neighbours at least twice daily during a cold emergency. The WHO recommends indoor temperatures above 18°C for healthy adults and above 20°C for vulnerable people.

Infants and Young Children

Infants cannot shiver — they have no active heat-generation mechanism other than limited brown adipose tissue. They become hypothermic rapidly in cold environments.

• Keep infants in skin-to-skin contact with a caregiver inside warm clothing.
• Dress in multiple thin layers.
• Never use extra blankets in the sleep space for infants under 12 months (suffocation risk) — instead dress them in wearable sleeping bags (sleep sacks).
• Monitor for signs of cold stress: cold to touch, pale or blue skin, lethargy, refusing to feed.

People With Certain Medical Conditions

Diabetics, those with cardiovascular disease, and those on certain medications (including some blood pressure drugs, antipsychotics, and sedatives) are at elevated risk of cold injury. Maintain their environment as warm as possible and monitor closely.

Community Warming

When a failure extends to whole neighbourhoods:

1. Community warming centres — local authorities typically open schools, libraries, community centres, and places of worship as warming centres during prolonged cold emergencies. Monitor local radio for locations.
2. Check on neighbours — particularly elderly or disabled people living alone.
3. Share resources — a household with a wood stove can warm several neighbours' worth of people in one space.
4. Carpooling to warming centres for those without transport.

Quick Reference

Situation	Action
Heating fails	Concentrate in one room; seal doors and windows
Clothing strategy	Base (wool/synthetic), mid (fleece/down), outer (windproof), hat
Sleeping without heat	Rated sleeping bag, hot water bottle, hat in bed
Emergency heating	Electric heater (if power) or indoor-rated propane/kerosene with CO alarm
Barbecue/charcoal for heating	Never indoors — CO will kill
Infant in cold	Skin-to-skin contact; multiple thin layers; do not use loose blankets
Elderly person feeling cold	Prioritise; check twice daily; warming centre if indoor temp drops below 18°C
Shivering stops without warming	Severe hypothermia — medical emergency
Person removing clothes in cold	Paradoxical undressing — severe hypothermia — insulate core immediately

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This article provides general guidance on cold weather survival without central heating. Hypothermia is a medical emergency — always call emergency services if you suspect severe hypothermia. Carbon monoxide detectors should be installed before using any combustion heating device.