Guide · Cold weather

Keeping a Home Warm When the Heating Stops

A house without heating does not become dangerous in an hour. It becomes uncomfortable slowly and then, if nothing is done, genuinely risky. Almost everything useful happens in the first evening.

How a house actually loses heat

A building sheds warmth in three ways at once, and it helps to picture them separately, because they call for different responses.

It loses heat through surfaces — walls, windows, the roof, the floor. Glass is the worst of these by a wide margin; a window loses heat far faster than the wall around it. It loses heat through air movement, which is the draught under a door and the gap around a letterbox, and which carries warmth away far faster than most people expect. And it loses heat by radiation to cold surfaces, which is the reason a room can feel cold even when a thermometer says it is not: you are radiating warmth to a cold window and feeling the loss.

Knowing this changes what you do. Sealing draughts and covering glass addresses two of the three and costs nothing. Trying to warm the whole volume of air in a house addresses none of them and is the thing most people attempt first.

Heat the person, not the building

This is the single most useful idea in this article, and it reverses the instinct most of us have.

A body produces heat continuously. The task is not to generate more warmth but to stop losing the warmth already being produced. Clothing does this by trapping still air, which is an excellent insulator as long as it is not moving. That is why several thin layers outperform one thick garment: each boundary traps another pocket of air.

• A base layer that moves moisture away from the skin. Damp clothing conducts heat away from the body many times faster than dry clothing. Of everything on this list, staying dry matters most.
• Middle layers that trap air — fleece, wool, a quilted jacket. Two medium layers beat one heavy one.
• An outer layer that blocks air movement, even indoors. A light windproof shell over a jumper makes a surprising difference in a draughty room.
• A hat. The old claim that most heat is lost through the head is an exaggeration, but an uncovered head is a large uninsulated surface and covering it is free.
• Something between you and the floor. Sitting on a cold sofa or standing on a cold tiled floor drains warmth steadily. Slippers with soles, a folded blanket under you, a rug.

Eating and drinking matter here too. A body with nothing to burn produces less heat. Warm food and hot drinks help more through the calories than through the temperature, and a flask filled while there was still power keeps that option available for hours.

Choosing one room and holding it

Once people are dressed properly, the next step is to stop defending the whole house and defend one room.

Pick the room with the fewest exterior walls and the smallest window area, ideally one that is not above an unheated space such as a garage. In most homes this is an interior bedroom or a small living room, not the kitchen and not the room everyone would normally choose for the view.

• Close the doors to every other room, and close internal doors on the way in and out. Each closed door is one less volume to warm.
• Block the gap under the chosen room's door with a rolled towel or a draught excluder.
• Draw the curtains at dusk, and tuck them behind a radiator shelf or windowsill rather than letting them hang over it. If there are no curtains, a blanket over a curtain rail, or cardboard taped over the glass at night, does the same job.
• Put everyone and the animals in together. Several bodies in a small room measurably raise the temperature, and the company helps as much as the warmth.

Overnight, the same room becomes the place everyone sleeps, which is both warmer and safer than people scattered through a cold house.

Sleeping warm

Bedding insulates in exactly the way clothing does, and the same rule applies: layers beat bulk, and what is under you matters as much as what is over you. A mattress compresses the insulation beneath a sleeping body, which is why people wake cold from below even under a thick duvet. A blanket or a camping mat underneath fixes it.

Going to bed in dry clothes, including socks and a hat, is sensible rather than excessive. A hot water bottle filled before the power went, or filled from water heated on a camping stove used outdoors, holds warmth for hours. Electric blankets obviously will not work, and should be switched off at the wall so they do not come on unattended when supply returns.

What not to do

• Never bring a generator, camping stove, charcoal grill, gas heater or any other fuel-burning device indoors — including into a garage, a porch, a basement or a conservatory — unless it was specifically designed and professionally installed for indoor use. These produce carbon monoxide, which has no colour and no smell. People die in their sleep without ever knowing anything was wrong.
• Never use a cooker or an oven to heat a room. A gas oven in an unventilated kitchen is the same hazard with a domestic appearance. An electric oven will not work anyway, and running one with the door open is a burn and fire risk around children.
• Treat candles and open flames with respect. In a dark house full of tired people and unfamiliar bedding on floors, an unattended flame is a genuine fire risk. Nothing burns while anyone sleeps.
• Do not drink alcohol to feel warmer. It widens surface blood vessels, which produces a sensation of warmth while the body loses core heat faster, and it blunts the judgement needed to notice that things are getting serious.

A working carbon monoxide alarm — battery powered, tested, with spare batteries — costs very little and is the only thing in the house capable of detecting the hazard above. Every home that burns anything should have one, long before an outage.

The pipes

In a genuinely cold snap the building has a problem of its own. Water expands as it freezes, and a frozen pipe can split; the damage usually appears when it thaws and begins to flow again, often into a ceiling.

What helps: keeping the house above freezing if there is any means to do so, opening the cupboard doors under sinks so warmer room air reaches the pipework against exterior walls, and knowing where the main water shut-off is so the supply can be closed quickly if a pipe does fail. Advice about letting a tap drip varies by country and plumbing system, and your water utility's guidance for your area is the one to follow.

If the property is going to be left empty in freezing weather, draining the system down is the thorough answer, and it is worth learning how before you need it.

Who is at greater risk

Cold is not equally dangerous for everyone in the house. Infants lose heat faster than adults because they are small relative to their surface area, and they cannot tell you. Older people may not feel cold as readily, may move less, and may take medication that affects circulation or temperature regulation. People with heart or lung conditions, reduced mobility, or who are unwell are all at greater risk.

Practically, this means checking on people rather than waiting to be told, and it means that the threshold for giving up on the house is lower when someone vulnerable is in it.

Knowing when to leave

There is a point at which the sensible decision is to stop managing a cold house and go somewhere heated. That point arrives earlier than most people's pride allows, and it arrives much earlier if there is a baby, an elderly relative or anyone unwell in the household.

The useful preparation is to decide in advance where that somewhere would be — a relative, a friend on a different part of the grid, a hotel, or a public warming centre if your local authority opens them — and to know how you would get there if the roads are bad and the car is low on fuel. A decision made calmly in October is a better decision than one made at two in the morning in February.

What to have before winter

In short

Put on more clothes before you do anything else. Close doors, cover windows, and gather everyone into the smallest room with the fewest outside walls. Sleep in layers, with something underneath you. Burn nothing indoors. Watch the people who cannot tell you they are cold, and leave for somewhere heated sooner than feels necessary.

None of it requires equipment, and all of it can be decided on an ordinary evening before the weather turns.

← Back to the main guide  ·  Read next: the first hour of a power cut →