Space heaters drain a battery in an hour or two, while electric blankets sip power. Learn the runtime logic and warmer, safer alternatives.
- Space heaters use about 1500 W, so a battery runs them for minutes to an hour or so.
- Electric blankets use far less and can last a night on a mid-size battery.
- Heat the person, not the room, and never burn fuel indoors.
When the power goes out in winter, the first idea is often to plug a space heater into a battery. It rarely works. Heating is the most power-hungry thing most households do, and a portable battery empties fast when asked to produce heat from electricity.
A heated blanket tells a very different story. It uses a small fraction of the energy and keeps one person warm for the whole night on a mid-size battery. Understanding why helps you pick the right tool.
Why space heaters drain batteries
A typical portable electric heater is rated at around 1500 W on its high setting. Heating air is simply energy hungry. Divide your battery's usable watt-hours by 1500 and you get the hours of heat. A battery with 1000 Wh of capacity gives roughly 0.85 x 1000 / 1500, about half an hour to just over half an hour at full output. That is rarely worth it.
- Many heaters exceed the continuous output of a typical portable power station, so they trip it off.
- Even if the station can handle it, the runtime is short.
- Heaters have no efficient way to cut consumption when set to high.
An electric heater is only realistic with a very large battery or a generator, and for a generator the rule is firm: outdoors only. See how to use a portable generator safely.
Why electric blankets work
An electric blanket warms you directly, not the whole room. Many use a small number of watts compared with a space heater, and some pull even less once warm because a thermostat cycles them on and off. Check the label on yours for the rated watts.
A rough example: a blanket rated at 100 W on high running half the time averages around 50 W. On a 500 Wh station, 500 x 0.85 / 50 gives roughly 8 hours. Lower settings stretch it further. Your blanket and settings will vary, so use the label or a watt meter.
Better results per watt
You get the most warmth from a battery by heating the person rather than the room.
- Use a heated blanket, heated throw or heated mattress pad on low or medium.
- Layer a sleeping bag rated for the temperature over a regular blanket.
- Pick one room to live in, close doors, and hang blankets over drafty windows.
- Wear a hat, socks and dry layers. Heat loss through the head and feet is real.
- Keep the station charged and only plug in the blanket, not extras.
See how to stay warm without power and keep your home warm during a power outage for more ideas.
Safety first
- Use heated blankets as the maker directs. Do not tuck them in tightly, fold them, or leave a damaged one running.
- Infants, people who cannot feel heat well, and anyone who cannot move away from the blanket should not use one unattended. Check the manufacturer's guidance.
- Never use a barbecue, camp stove, charcoal or a gas oven to heat living space. These produce carbon monoxide.
- Test your carbon monoxide alarms, and keep them fresh.
How to size your battery for warmth
Add up the hours you want warmth, multiply by the blanket's average watts, and add margin. For a night, a mid-size battery can run a blanket with room to spare. Pair it with a phone charge and a light, and you still have a day left over. The power station hub and the heat and light hub list what to consider. Cold also cuts battery capacity, so keep the unit inside your sleeping area. See power stations in cold weather.
A simple winter routine
Charge the battery fully before cold weather arrives. When the power goes out, pick one small room, close the door, and heat the bed before you get in by turning the blanket on a half hour early. Then turn it down or off once you are warm under layers. Check on children and older relatives often, and watch for signs of cold stress such as shivering that will not stop, confusion or numb skin. If anyone is struggling to stay warm, go to a warming centre or a friend's home with power rather than staying put.
Quick answers
Can any power station run a space heater?
Some high-output units can power one briefly, but runtime is short. Check the continuous output and capacity.
How long will a heated blanket run on a battery?
Divide usable watt-hours by the blanket's average watts. A low setting on a mid-size battery often covers a night.
Is it safe to leave a heated blanket on all night?
Follow the maker's instructions. Many modern ones have auto shutoff, but check yours and do not use a damaged one.