5 things that help you stay warm when the heat goes out
Independently chosen — nobody pays to be on a list, and we say what didn't make it. How we pick the 5.
The five, at a glance
1Close down to one room and seal the door2Layer a sleeping bag over your duvet, not instead of it3Use a hot water bottle at your core, not your feet4Wear a base layer directly against your skin, not cotton5Eat something warm and calorie-dense before you sleepClose down to one room and seal the door
Trying to stay warm in a whole house when the heating is off is like trying to fill a bathtub with the plug out. Your body heat, a few other people, and whatever warmth you can trap are not remotely sufficient for an open-plan flat or a hallway — but they are surprisingly sufficient for a small interior room with the door shut. The non-obvious part is that a rolled-up towel along the bottom of the door makes a more meaningful difference than an extra blanket: convection loops bleed heat constantly through that gap, and stopping them is as effective as adding another layer.
Layer a sleeping bag over your duvet, not instead of it
The instinct is to drag out the camping sleeping bag and sleep inside it. The better move is to put it on top of your existing duvet. A sleeping bag used as a replacement loses efficiency because the mattress below you is wicking heat away; used as an outer layer, it creates a second trapped-air barrier over the duvet, and tog ratings add roughly. More practically: a three-season bag rated to around 0–5°C sitting on top of your 4-tog duvet is a combination most people already own without realising how effective it is.
Use a hot water bottle at your core, not your feet
A hot water bottle holds heat for four to six hours with zero ongoing energy use — it's warming you directly by conduction rather than trying to heat the air, so none of it is wasted on ceilings. The less obvious bit: most people put it at their feet, which helps, but the better placement is against your lower back or abdomen. Your core temperature is what the body is defending; warm the core and the extremities follow. Your feet feel cold because your core has cut blood flow to them — addressing the feet directly is treating the symptom.
Wear a base layer directly against your skin, not cotton
Most people pile on a big jumper over a cotton t-shirt and wonder why they're still cold. Cotton absorbs moisture and then sits damp and cold against the skin — it actively makes you colder as the night goes on, particularly if you're moving or sleeping. A thin thermal or synthetic base layer worn next to the body traps a small column of warm air against the skin and keeps moisture away from it. This is the whole mechanism behind why mountaineers stay comfortable in conditions your living room will never approach. Three thin layers beat one thick one because each layer traps an insulating air gap between it and the next.
Eat something warm and calorie-dense before you sleep
Your body generates heat as a byproduct of digestion, and this thermogenic effect is meaningful enough to make a real difference over a six-hour sleep. Fats and complex carbohydrates produce more metabolic heat than protein or sugar; a bowl of porridge, leftover pasta, or peanut butter on toast before bed raises your core temperature for several hours in a way that going to bed hungry simply does not. It is not a substitute for insulation, but combined with the other things here it closes the gap. Warm drinks reinforce it, though their heat effect is short-lived compared to solid food — and avoid alcohol, which feels warming but dilates surface blood vessels and accelerates heat loss.
What didn't make the list
This comes up in every cold snap and it kills people. Gas ovens left open for warmth, camping stoves run inside, propane or paraffin heaters in a sealed room — all of these produce carbon monoxide in enclosed spaces, and CO has no smell and gives no warning before it becomes dangerous. This is not a logistics-of-inconvenience problem; it is a life-safety matter, and it does not belong on this list. For guidance on safe heating options during extended outages, Ready.gov and the Red Cross are the right starting point. A sleeping bag and some layering will get you through the night without that risk.
It actually works in principle — a trapped air layer over single glazing does slow heat loss — but in practice it requires the room to be cold enough that you can see the difference, it looks alarming, and it is fiddly enough at midnight that most people either do it badly or give up. The room-consolidation and sleeping-system steps above will get you further with less effort. Worth knowing about if you are in a very draughty older property and facing a multi-day outage; not worth prioritising on night one.
Questions people ask
In a well-insulated modern home in a typical UK or northern European winter, indoor temperature usually drops around 1–2°C per hour in the first few hours, then slows as the house reaches equilibrium with outside. In a draughty older property during a hard freeze, it can go faster. The practical upshot is that you usually have a few hours before conditions become genuinely uncomfortable for sleeping — the sleeping-bag-and-one-room approach gives you a real window to get settled before things deteriorate. The threshold worth paying attention to is around 13–16°C: below that, prolonged exposure becomes a health concern for infants, older people, and anyone with certain medical conditions. If you have vulnerable people in the household and the outage is forecast to last more than a night, moving somewhere warmer earlier is the sensible call.
A single candle puts out roughly 80 watts of heat — about the same as a large light bulb — and most of that rises straight to the ceiling. In a small sealed room with several candles and several people, they contribute a small but real amount of warmth. They are not a heating system, but they are not nothing either. The practical risks (fire, tipping over, sleeping near an open flame) mean you should never leave them unattended and should extinguish them before sleeping. Use them for light and morale, treat any heat they provide as a bonus, and do not rely on them as a strategy.
If you have mains power, a plug-in electric space heater — particularly an oil-filled radiator — is a perfectly safe and practical solution for the sealed room you have nominated. A 1,500-watt fan heater will warm a small closed room reasonably quickly, and oil-filled radiators are quieter and maintain heat better for overnight use. Run it in your one sealed room rather than trying to heat the whole flat, and check the circuit can handle extended use before relying on it overnight. Basic models are available for under £30 and are a more useful emergency purchase than most dedicated prep gear.
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