When the power goes out in winter, warmth is the first thing you lose and the hardest to improvise. A quality vacuum flask lets you bank heat while you still have it: boil the kettle before an expected outage, or heat water on a camping stove, and a good flask keeps it hot for up to 24 hours. A hot drink, a warm meal or a filled hot water bottle does an enormous amount to keep a cold household comfortable and calm.
Unlike anything electrical, a flask needs no power, no fuel and no maintenance — it simply holds the heat you put into it. That makes it one of the cheapest and most reliable pieces of cold-weather preparedness, as useful in a stranded car or on a hill walk as it is during a power cut at home.
Fill it at the first sign of an outage or before heading out in cold weather. At home it means hot drinks and instant meals without repeatedly firing up a stove; in the car it is a lifeline if you are stranded in winter traffic; on the hill it keeps a hot drink ready when you stop. Pre-warm it with a splash of boiling water first for the longest heat retention.
It works the other way too: filled with ice and cold water it keeps drinks cold through a summer heatwave. Rinse and dry it fully between uses, and store it with the lid off so it stays fresh.
A vacuum between two stainless walls is what stops heat escaping. Stainless is tough and won't shatter like glass-lined flasks of old, so it survives being knocked about in a bag or car boot.
Look for a stated performance such as hot for up to 24 hours and cold for 24 hours. A larger flask holds heat longer than a small one, so size it to how many people you are keeping supplied.
A stopper that seals reliably prevents spills in a bag, and a lid that doubles as a cup means you can share a hot drink without extra kit. Check the closure is robust and easy to use with cold hands.
Around 0.5L suits one person out and about; 1.2L or more is better for a family at home during an outage, holding enough for several hot drinks or a couple of instant meals.
Filling a cold flask wastes heat straightaway. Rinse it with boiling water first, tip that away, then fill — you'll noticeably extend how long it stays hot.
A pocket-sized flask empties after a mug or two. For power-cut use at home, a 1.2L flask keeps a household in hot drinks for far longer.
Left shut with moisture inside, a flask can grow musty. Dry it fully and store it with the lid off so it's ready and fresh when you need it.
A rugged stainless steel vacuum flask that keeps drinks hot for up to 24 hours and cold for 24 hours. The 1.2L size suits a household through a power cut, with a leak-proof stopper and an insulated cup lid for sharing a hot brew.
A wide-mouth vacuum food flask that keeps a hot meal hot for hours — the answer to warm food during a power cut or a cold day out when the stove stays packed away. The wide neck takes stew, soup or porridge and includes a folding spoon. Thermos's vacuum insulation is genuinely long-lasting rather than a token claim.
A rugged vacuum food flask that keeps a stew or soup hot for many hours, which matters in a cold power cut or a long day outdoors. Wide-mouthed and near-indestructible, it's the classic that earns its place in emergency kit.
A standard 1-litre natural rubber hot water bottle with a soft fleece cover, and one of the cheapest ways to stay warm through a winter power cut. Boil a kettle on a camping stove, fill it, and it holds heat for hours in a bed or on your lap without drawing a single watt. Simple, reliable warmth that belongs in every cold-weather kit.
An inexpensive rectangular 3-season bag that's a sensible warmth backup for a car, caravan or home emergency stash rather than serious winter camping. It packs down into an included sack and gives you a warm layer if the heating fails. Rated for milder conditions, so pair it with extra layers or a liner for genuinely cold nights.
A lightweight down-filled mummy sleeping bag that stuffs down small enough to live in a grab bag or the bottom of a rucksack. Down gives a good warmth-to-weight ratio for its packed size, making it a sensible backup for cold nights, power cuts or an unplanned stopover. Keep it dry, as down loses loft when wet, and it will hold its warmth well.
A roomy two-person bag with a built-in pillow and hood from a trusted British outdoor brand, rated as a 2–3 season bag for milder camping and festivals. It also doubles as a warm, packable layer to keep by the sofa or in the loft for a winter power cut, when keeping two people warm together is more efficient than heating a room. It's bulkier than a solo mummy bag, so treat it as home or car kit rather than something to carry far.
A merino-blend long-sleeve top and long johns designed to trap warmth and wick moisture next to the skin. Merino stays warm even when slightly damp and resists odour over several days, which makes it a strong base for a cold power cut, a winter walk or a car left stranded in bad weather. Danish Endurance is a well-reviewed outdoor-basics brand.
A pair of rechargeable hand warmers with three heat settings that clip together magnetically, and each one doubles as a small 5,000mAh power bank for a phone top-up. Reusable is the sensible long-term choice over disposable sachets if you are out in the cold regularly or facing a winter power cut. Both charge and discharge over USB-C.
Compact camping stove for boiling water and cooking food. Essential for hot meals and water purification.
Insulated sleeping bag rated for cold temperatures. Essential for any overnight emergency or planned outdoor stay.
Single-use or reusable heat packs that provide warmth for 6–12 hours. Critical for preventing cold injuries.
A refillable rubber bottle that holds warmth for hours from a single kettle or pan of hot water — a cheap, no-power way to stay warm in bed or a cold room during a power cut.
Practical, proven methods to keep yourself and your family warm when the heating fails during a British winter — from layering techniques to emergency heat sources.
A practical UK household plan for getting through a two-day power cut: light, phone charging, food, warmth, water, safety and when to ask for help.
A practical UK winter home kit for the first three days of a storm, power cut, cold snap or water disruption, with calm priorities and sensible gear.
