Space heater, fireplace and wood stove safety during a power outage¶

When the power fails in winter, the instinct to get warm quickly leads many people to heat sources that were never meant for indoor use. Every winter, house fires and carbon monoxide poisonings follow outages, and most of them involve a heater that was placed too close to something that burns, a stove that was running without a proper chimney, or a fuel burning device that was brought inside from the garage or the yard.

This guide explains how to use a space heater, a fireplace and a wood stove with as little risk as possible, how to tell which heat sources are safe, and which ones must never come indoors. It also covers alarms, ventilation, ash disposal and the warning signs that mean you must leave the house. For the weather and outage side of the problem, see winter power outages and prolonged blackouts and no heat in winter.

Do this now¶

1. Check that you have a working battery powered or battery backup carbon monoxide alarm and a smoke alarm. If you do not, stay with a friend or relative or go to a warming center until you have them.
2. Turn off and unplug anything you do not need, and choose one heat source designed for indoor use. Do not run several at once.
3. Keep every heat source at least 1 meter (3 feet) from curtains, bedding, furniture, clothing, paper and anything else that burns.
4. Never use a gas oven, charcoal grill, camp stove, patio heater or generator to heat a room. They produce carbon monoxide, and people die from it every winter.
5. If anyone in the home has a headache, dizziness, nausea, confusion or sleepiness, get everyone outside into fresh air and call your local emergency number (911 in the United States and Canada, 112 across the European Union, 999 in the United Kingdom). See emergency numbers.
6. Turn off every heater and let the fire go out before you sleep or leave the room, unless a properly installed and maintained wood stove is burning down under your supervision.

The two dangers: fire and carbon monoxide¶

Almost every serious accident with emergency heating falls into one of two groups. The first is fire, which starts when a heat source touches or ignites nearby materials, when ash or embers are mishandled, or when a chimney that has not been cleaned catches fire. The second is carbon monoxide poisoning, which happens when fuel burns without enough air or without a proper vent to the outside.

Carbon monoxide is a colorless, odorless gas. You cannot see it, smell it or taste it. It binds to the blood and stops it carrying oxygen, so people become drowsy and may fall asleep without noticing they are being poisoned. Sleeping people and small children are at particular risk. The Centers for Disease Control and Prevention (United States) and Health Canada both stress that a working carbon monoxide alarm is the only way to detect it early.

Carbon monoxide: what to know¶

• Any device that burns fuel can produce it, including gas, propane, kerosene, oil, charcoal, wood and gasoline.
• Early symptoms feel like flu without a fever: headache, dizziness, weakness, nausea, chest tightness and confusion.
• Symptoms often improve outdoors and return indoors. If several people feel unwell at the same time, or pets are sick, suspect carbon monoxide.
• At high levels, a person can lose consciousness within minutes and die.

See carbon monoxide and carbon monoxide and smoke inhalation first aid for symptoms and first aid.

Alarms: your most important device¶

• Install a carbon monoxide alarm outside every sleeping area and on every level of the home, including the basement.
• Choose alarms with battery backup so that they work in an outage. Check and replace batteries on a regular schedule, and replace the unit according to the manufacturer's instructions, often every 5 to 10 years.
• Test each alarm monthly by pressing the button.
• If the alarm sounds, leave at once. Do not open windows or look for the cause first. Call your local emergency number from outside, and do not go back in until the fire service says it is safe.
• Install smoke alarms in every bedroom, outside each sleeping area and on every level, and test them each month.

What never to use indoors¶

The following devices produce carbon monoxide or fire hazards that cannot be controlled in a living space. Do not use them indoors, in a garage, in a tent attached to the house, in a basement or on an enclosed porch, whatever the weather.

Never burn charcoal or any fuel in a closed vehicle either. Do not sleep in a car with the engine running, particularly if snow may block the tailpipe. See car breakdown for winter vehicle safety.

Electric space heaters¶

Electric space heaters make no carbon monoxide, but they cause many house fires. They draw a lot of power, so they only work during an outage if you have a generator or battery system that can supply them. Do not expect an extension cord and a small power station to run a heater.

Choose a safe heater¶

• Look for a recognized safety mark from a testing laboratory, such as UL or ETL in North America, or the CE or UKCA mark in Europe and the United Kingdom. Check the label.
• Choose a heater with automatic tip over shutoff and overheat protection.
• Prefer models with a thermostat and a thick, short power cord.
• Oil filled radiators and heaters with ceramic elements tend to have cooler surfaces than those with exposed hot coils.
• Do not use damaged, old or recalled heaters. Check your model against your national product safety recall list.

Use it safely¶

1. Place the heater on a flat, hard, level, non flammable surface. Never put it on a carpet, a bed, a couch or a table where it could be knocked over.
2. Keep a clear zone of at least 1 meter (3 feet) on all sides, and above. Move bedding, curtains, clothes, papers and furniture away. Make this a kid and pet free zone.
3. Plug it directly into a wall outlet or the generator. Do not use extension cords, power strips or surge protectors, which can overheat and start a fire. If you must use an extension cord, choose a heavy duty cord rated for the heater load and as short as possible.
4. Do not run the cord under rugs or furniture, and keep it from being stepped on.
5. Never leave it on while you sleep, when you leave the room or when you leave the house. Turn it off and unplug it.
6. Check the cord, plug and outlet for heat. A hot plug or a smell of burning plastic means you must turn it off and stop using it.
7. Do not dry clothes on it or cover it.
8. Never use a heater in a bathroom or near water, unless it is designed for that use.

Using electric heaters with a generator¶

When you run a heater from a generator, the generator must be outdoors, at least 6 meters (20 feet) from windows and doors, with the exhaust pointing away from the house. Make sure the generator has enough capacity for the heater, which often draws 1,500 watts or more. Overloading can damage the generator or trip it. See generator safety for the full list of rules.

Fireplaces¶

A fireplace that is in good condition can supply useful warmth in an outage, but most of the heat goes up the chimney. A fireplace without a stove insert may keep one room only slightly warmer, and it can draw cold air through the rest of the house. Use it as a supplement, not your only source of heat.

Before you light a fire¶

• Have the chimney inspected and cleaned each year by a qualified chimney sweep. Creosote, a tarry residue, builds up inside flues and can ignite. See chimney fire and creosote hazard.
• Check the flue for blockages, such as snow, ice, nests, leaves or fallen masonry. Look at the chimney cap from the ground, and do not climb on the roof in winter.
• Open the damper fully before you light the fire, and keep it open until the ashes are cold.
• Make sure the glass doors and fireplace screen are in good condition. A mesh screen stops sparks from escaping.
• Check that the hearth extends far enough to catch falling embers, and that nothing flammable is on the mantel, such as stockings, paper or decorations.
• Remove rugs and furniture from the front of the fireplace.

What to burn¶

• Burn seasoned hardwood that has dried for at least 6 months, preferably a year. Wet or green wood smokes heavily and builds up creosote.
• Burn small amounts at a time, and build the fire on the grate.
• Never burn trash, plastic, cardboard, wrapping paper, painted or treated wood, pressure treated lumber, or driftwood. They release toxic fumes and may flare.
• Never use gasoline, lighter fluid or other flammable liquids to start or revive a fire.
• Do not use a charcoal briquette in the fireplace, since it produces much more carbon monoxide than wood.
• Avoid artificial logs together with real wood, and follow the label if you use one. Burn one at a time.

Burn it safely¶

1. Keep the fire small and attended. Do not leave it burning when you leave the room or go to sleep.
2. Keep the screen closed, and keep children and pets at least 1 meter (3 feet) away.
3. Keep a fire extinguisher rated for household use and a bucket of sand nearby. Know how to use the extinguisher.
4. Never close the damper while embers still glow, because this traps carbon monoxide in the house.
5. Let the fire burn down completely, and do not leave a smoldering fire when you go to bed.
6. Smoke coming into the room means a problem with the flue. Put out the fire, open a window and call a professional, and treat it as a carbon monoxide risk.

Ash disposal¶

Ashes can stay hot enough to start a fire for days. Wait at least 24 hours, ideally longer, before removing them. Scoop them into a metal container with a tight lid, place the container on a non flammable surface such as concrete or bare ground, at least 3 meters (10 feet) from the house, garage and other buildings, and keep it away from wood decks, fences and snow free dry grass. Do not use paper bags, cardboard boxes or plastic buckets. Leave the ashes in the closed metal bucket for several days before spreading them, and soak them with water if you wish. Never vacuum warm ashes.

Wood stoves and inserts¶

A properly installed wood stove is much more efficient than an open fireplace, and it is one of the better ways to keep a home warm in a long outage. The risks come from poor installation, a dirty chimney, overloading the firebox, and unattended burning. See wood stove and pellet stove runaway overfiring and hopper burn back for what to do when a stove runs out of control.

Before the winter¶

• Make sure the stove was installed according to local building codes and the manufacturer's instructions, ideally by a certified installer. Many insurers require this.
• Clean the chimney and stove pipe each year, and inspect for cracks, rust, loose joints and creosote.
• Check the stovepipe connections, door gasket and glass, and replace anything damaged.
• Keep a metal bin for ashes and a stove glove or thick leather gloves near the stove.
• Stock dry, seasoned wood, stored off the ground, with enough for several days of use.

Clearance and floors¶

Keep combustible materials away from the stove at the distance listed in the manual, commonly about 1 meter (3 feet), and further if the manual says so. The stove must sit on a non combustible floor protector that extends beyond the stove on all sides. Do not store wood, papers, clothing or furniture close enough to heat up. Do not hang laundry on the stove or near the pipe.

Operating the stove¶

1. Start the fire with kindling and dry paper, and use the stove's air control to establish a strong flame. A smoldering fire creates creosote and smoke.
2. Burn small to moderate loads, according to the manual. Overfiring, which means burning too hot, can warp the stove and set the chimney on fire.
3. Do not close the air supply fully to make the fire last longer overnight, since that creates dangerous gases and creosote.
4. Keep the stove door closed except when loading.
5. Never use flammable liquids to start the fire.
6. Add logs carefully, and let the fire burn down before opening the door fully, to avoid a flare of smoke or flame into the room.
7. Check the stove, the pipe and the area around it frequently, and look for glowing metal. Dull red glow on the pipe means overfiring, so reduce the air at once.
8. If you see flames or hear a roaring from the chimney, close the air supply, get everyone out and call your fire service. See chimney fire and creosote hazard.

Pellet stoves and other powered appliances¶

Pellet stoves, many gas fireplaces with fans, and many furnaces depend on electricity for the auger, fan or ignition. In an outage they may stop, and a pellet stove can fill the room with smoke if the exhaust fan fails. See pellet stove power outage smoke rollback. Do not try to run these stoves by hand unless the manufacturer says a backup is possible. A battery backup unit made for the appliance can keep it working, so ask the manufacturer.

Fuel burning room heaters: propane and kerosene¶

Some people keep propane or kerosene heaters for emergencies. They are legal and safe only in some places and only when used exactly as designed, and several countries and states restrict or ban kerosene heaters indoors.

• Use only heaters labeled for indoor use, with an oxygen depletion sensor and tip over shutoff, and follow the label strictly.
• Use only the fuel the manufacturer specifies. For kerosene, use clear 1 K kerosene. Never use gasoline, which can explode.
• Refuel outdoors, only when the heater is off and cool, and never overfill.
• Crack a window slightly, as the manual says, so fresh air enters the room.
• Keep it on a flat, stable surface at the clearances listed in the manual.
• Do not use these heaters in a bedroom or while you sleep.
• Keep carbon monoxide and smoke alarms working in the same room and on every floor.

For more detail, see kerosene heater, ventless propane heater and indoor combustion safety.

Choosing the safest option: a decision flow¶

flowchart TD
    A["Power is out and the home is cold"] --> B{"Do you have working<br/>carbon monoxide and smoke alarms?"}
    B -->|"No"| C["Go to a warming center<br/>or a safe home"]
    B -->|"Yes"| D{"Do you have an approved<br/>indoor heat source?"}
    D -->|"No"| E["Close off one room, add layers<br/>and blankets, or leave"]
    D -->|"Yes"| F{"Is it electric on a generator<br/>outdoors and 6 meters away?"}
    F -->|"Yes"| G["Use it 1 meter from anything<br/>that burns and never while asleep"]
    F -->|"No"| H{"Is it a clean flue wood stove<br/>or fireplace?"}
    H -->|"Yes"| I["Burn dry wood, use a screen<br/>and stay awake and alert"]
    H -->|"No"| J["Do not use it indoors"]
    G --> K{"Headache, dizziness<br/>or alarm sounding?"}
    I --> K
    K -->|"Yes"| L["Go outside and<br/>call emergency number"]
    K -->|"No"| M["Keep checking alarms<br/>and heat sources"]

Warm without burning anything¶

The safest heat is the heat your body already makes. These steps work with any heat source, and they are the best plan when you have no approved indoor heater.

• Pick the smallest interior room, and close the door. Block gaps with towels.
• Hang blankets over windows and doorways. Seal drafts with tape and cardboard.
• Wear several layers, including a hat, scarf, gloves and thick socks. Stay dry.
• Put on a base layer of wool or synthetic fabric, not cotton.
• Sleep in a sleeping bag rated for cold weather, on a pad or mattress that insulates you from the floor.
• Huddle with others in the same room, including children and pets.
• Eat regularly and drink warm drinks. Avoid alcohol.
• Move around from time to time to keep warm, but avoid sweating.

For the longer plan, see keeping warm indoors during a multi day winter grid collapse. Hot water bottles filled with warm, not boiling, water and wrapped in cloth are safe warmers for a bed. Do not warm bricks or stones in a fire for the bed, and do not use heating pads or electric blankets without power.

Warning signs you must leave¶

Leave the house, take pets with you, and call your local emergency number if you notice any of these:

• The carbon monoxide alarm sounds.
• Anyone feels dizzy, has a headache, nausea or confusion, especially several people together.
• Smoke or fumes come from a stove, fireplace, heater or furnace into the room.
• A smell of gas, which is a rotten egg odor added to natural gas, or hissing near a gas appliance. Do not use switches or phones inside.
• A heater, cord or outlet is hot, sparking, melting or smells of burning plastic.
• A chimney fire makes a roaring or rumbling sound, or flames or sparks come from the top.
• The stove or pipe glows red.

Once outside, move away from the house, and keep everyone together. Do not go back in for belongings. If someone is unconscious or not breathing normally, start CPR. See CPR.

Fire safety habits during an outage¶

• Keep a flashlight and a battery lamp in each room, and avoid candles. If you must use candles, put them in sturdy holders on a stable surface, away from anything that burns, and put them out when you leave the room or sleep.
• Keep exits clear, and plan two ways out of every room. Practice your family fire escape plan. See home fire escape plan.
• Keep a fire extinguisher near the exit of the kitchen and near any stove. See home fire extinguisher selection.
• Do not smoke while using oxygen equipment, and keep oxygen at least 2 meters (6 feet) from open flames and heaters.
• If clothing catches fire, stop, drop to the ground and roll, covering your face with your hands. Call your local emergency number.
• Check on people who live alone, older adults and anyone whose medical equipment needs power.

Using heat when a generator is the only power¶

A generator can run a space heater, a furnace fan and a few lights, but it brings the highest risk of all. Make sure that you:

1. Place the generator outdoors, at least 6 meters (20 feet) from the house, with the exhaust pointing away from openings.
2. Never run it in a garage, a shed, a basement, a porch or near a window or vent.
3. Install working battery powered carbon monoxide alarms before you start it.
4. Use heavy duty cords in good condition, and plug the appliance directly into the generator.
5. Never connect the generator to a house outlet or a circuit panel without a transfer switch installed by a licensed electrician.
6. Keep the unit dry, but do not put a tarp over it in a way that blocks air flow.
7. Turn it off and let it cool before you refuel, and store fuel outdoors in approved containers.

See generator safety, and backup power station and solar generator sizing for a way to run small loads without exhaust.

Checklist for safe emergency heating¶

• Carbon monoxide alarm with battery backup in every sleeping area and level
• Smoke alarm tested this month
• Chimney inspected and cleaned this year
• Space heater has tip over shutoff and a safety mark
• Clear zone of 1 meter (3 feet) around every heat source
• Dry, seasoned wood stored and ready
• Metal ash bucket with lid and a fire extinguisher at hand
• No grill, camp stove, patio heater or generator inside
• Phone charged and the emergency number saved
• Plan to leave and go to a warming center if the home gets too cold

Common mistakes that cause fires and poisonings¶

Investigators find the same errors again and again after outage related fires and poisonings. Knowing them is one of the cheapest ways to avoid being the next case.

• Moving a grill or camp stove into a garage or tent because the wind is cold outside. Opening the door does not make this safe.
• Running a generator near a window because the cord does not reach. Exhaust can enter the house through windows, doors, vents and gaps even from several meters away.
• Plugging a space heater into a power strip with other devices, which overloads the strip.
• Drying wet gloves, socks or boots on top of a heater or too close to a stove.
• Falling asleep with the heater on, especially in a chair or on a couch.
• Piling wood against the stove, or storing kindling on the hearth.
• Using lighter fluid on a fire that has gone out or is burning slowly, which causes flash fires.
• Leaving the damper or flue closed because the room felt drafty.
• Putting hot ashes in a cardboard box, a plastic bag or a trash can.
• Ignoring a faint smell of smoke, a short beep from an alarm, or a headache that disappears when leaving the house.

Special situations¶

Renters, apartments and shared buildings¶

In an apartment you may not be allowed to use a wood stove, fireplace or fuel burning heater, and carbon monoxide can travel between units. Ask your landlord about the rules and about alarms before winter. If power fails, an electric heater on a safe supply, layers and a warming center are the realistic options. Never use a grill on a balcony that is under another balcony, and never bring one inside.

Homes with babies, pregnant people and people with lung or heart disease¶

These groups are more sensitive to both cold and smoke. Smoke from a wood fire, a smoldering stove or a poorly vented heater can worsen asthma, chronic lung disease and heart conditions. If anyone has these conditions, favor a heater that makes no smoke, keep them in a room with good ventilation from a working flue, and move them to a warm place early rather than relying on risky heat.

Pets¶

Pets are curious and often sleep close to heat. Keep them away from heaters, stoves and hot glass, and use a screen or gate. Birds are especially sensitive to carbon monoxide and smoke, and a sick bird may be an early warning. See pets in emergencies.

When to have a professional check your system¶

Call a licensed technician if a furnace or boiler has been off for many days, if you smell gas or soot, if flames burn yellow instead of blue, if there is condensation on windows near a gas appliance, or if the carbon monoxide alarm has gone off even once. After a long outage, heating equipment may have been damaged by cold or by ice in the flue.

Frequently asked questions¶

Can I heat a room with my gas oven during a power outage?¶

No. A gas oven or stove is not designed to heat a home, and it releases carbon monoxide and can start a fire. Heat one small room with an approved heater or use layers and blankets, and go to a warming center if the home is too cold.

How far should a space heater be from furniture and curtains?¶

Keep at least 1 meter (3 feet) of clear space on every side of the heater, and keep children and pets out of that zone. Put the heater on a flat, hard surface and plug it directly into a wall outlet or generator rather than an extension cord. Turn it off when you sleep or leave the room.

Is it safe to leave a wood stove burning overnight?¶

Only a properly installed, well maintained stove that is burning dry wood, with clear chimney and working alarms, can burn overnight, and even then there is some risk. Never close the air supply fully to stretch the burn, and never go to sleep with a smoldering fire in a fireplace. Check the manual and consider using an electric heater, extra layers or a warming center if you are unsure.

What are the first signs of carbon monoxide poisoning?¶

The first signs are headache, dizziness, weakness, nausea, chest tightness and confusion, which can feel like the flu without a fever. If several people or pets feel unwell at the same time, or the alarm sounds, get everyone outside into fresh air and call your local emergency number. Do not go back inside until responders say it is safe.

Sources checked¶

Guidance on this page was checked against the Centers for Disease Control and Prevention (United States) pages on carbon monoxide poisoning and generator safety, the National Fire Protection Association (United States) heating safety advice, the United States Fire Administration heating fire guidance, Ready.gov and the Federal Emergency Management Agency (United States) power outage and winter storm pages, the American Red Cross home fire and winter storm safety pages, the National Health Service (United Kingdom) carbon monoxide advice, the UK Fire and Rescue Service home safety advice, Health Canada guidance on carbon monoxide and home heating, and Natural Resources Canada advice on wood heating. Where distances and times differ between agencies, the more cautious figure is used.

Learn first aid¶

A hands-on first aid course teaches you to treat burns, smoke inhalation and carbon monoxide exposure with confidence. The Red Cross, St John Ambulance and local providers offer short courses that include CPR. Book one before next winter and go with a family member.

Related guides¶

• Carbon monoxide
• Chimney fire and creosote hazard
• No heat in winter
• Generator safety
• Winter power outages and prolonged blackouts