How to Stay Warm During a Power Outage in Canada

Quick answer

Yes, you can often stay warmer during a power outage, but the best method depends on what normally heats your home and what backup energy you actually have.

If you have a natural-gas, propane, or oil furnace, restoring safe backup electricity to the existing furnace can make far more sense than burning generator fuel or battery capacity on portable resistance heaters. If you only have a portable battery, warming people directly and concentrating in one practical room usually stretches stored energy much further than trying to recreate whole-home heat.

Do not treat “propane heater,” “indoor safe,” or “battery powered heater” as self-explanatory product categories. Exact Canadian appliance instructions matter, and the physics of watt-hours matters.

Best outage-heating options at a glance

First decision: are you heating a person, a room, or the house?

Those are three different engineering problems.

Heating a person can mean dry layers, ordinary bedding, a sleeping bag, or a modest electrical warming load placed close to the body. The useful heat does not have to warm every cubic metre of room air first.

Heating one occupied room means choosing a practical zone, reducing unnecessary air exchange with the rest of the house, and adding enough safe heat to slow the room’s losses.

Heating the whole house means replacing heat at roughly the rate the building is losing it. In serious Canadian cold, that can be a large continuous load. If the normal heating appliance can be safely restored with backup electricity, it often deserves attention before portable heaters.

The fourth problem is protecting the building. Keeping people comfortable in one room does not guarantee that pipes in exterior walls, crawlspaces, garages, or other remote areas are protected. Use the frozen-pipe guide as a separate property-protection plan.

The battery-powered heater problem is mostly an energy problem

A heater can be electrically efficient and still be a terrible battery load.

A resistance heater converts electrical energy into heat at the point of use. The basic outage math is simple:

energy used (Wh) = heater watts × hours

So a 1,500 W heater running continuously uses:

• 750 Wh in 30 minutes
• 1,500 Wh in 1 hour
• 12,000 Wh in 8 hours

That is why tiny rechargeable products marketed as “battery operated heaters,” “cordless heaters,” or “battery powered space heaters” need a reality check. A compact battery can provide useful personal warmth, but meaningful room heat requires meaningful stored energy.

Do not judge a battery heater by mAh alone

Milliamp-hours are not an energy measurement unless you also know the battery voltage.

For example, a 10,000 mAh battery is 10 Ah. If its cells are nominally 3.7 V, the stored energy is roughly:

10 Ah × 3.7 V = 37 Wh

Thirty-seven watt-hours cannot secretly become hours of kilowatt-scale room heat. It can still be useful in a hand warmer, heated vest, or another low-power personal device. The category label is the problem, not the existence of the battery.

Health Canada also warns that electrical products sold online can be unsafe or non-compliant. Plug-in electrical products should carry a recognized Canadian certification mark such as CSA, cUL, or cETL. See Health Canada’s current electrical-product guidance and online-shopping guidance.

How long will a power station run a space heater?

Here is a deliberately simple comparison. It assumes 85% of the battery’s nameplate Wh reaches the AC load after conversion and reserve losses. That is an illustration, not a specification for every power station. Actual delivered energy changes with inverter design, load, temperature, battery condition, and manufacturer limits.

The calculation is:

runtime ≈ battery Wh × 0.85 ÷ load W

Two caveats matter:

1. The inverter still has to support the heater’s continuous wattage. A 1 kWh battery does not automatically come with a 1,500 W inverter.
2. A thermostat may cycle a heater on and off, so real runtime can be longer than the continuous-load example. The duty cycle depends on the room, weather, setpoint, and heater. Do not assume a universal percentage.

For your own battery and load, use ReadyHome’s portable power station runtime calculator rather than treating this table as a promise.

Why heated blankets and clothing can stretch battery energy

If the goal is keeping people warm rather than maintaining a whole room at normal temperature, lower-power personal warming can change the battery equation dramatically.

The useful comparison is not “heated blanket versus space heater efficiency.” Both eventually turn electrical energy into heat. The advantage is where the heat goes. A blanket, pad, vest, or other personal warmer can put heat close to the person instead of first warming the room air, walls, windows, furniture, and every leakage path to outdoors.

Use the exact product wattage in the runtime calculator. Do not assume all blankets or heated clothing draw the same power.

For plug-in products, look for recognized Canadian electrical certification and follow the manufacturer’s instructions, especially around sleeping, folding, moisture, children, reduced sensation or mobility, and unattended use.

If you have a fuel-burning furnace, power may be the smaller problem

A modern natural-gas, propane, or oil furnace normally needs electricity even though the fuel itself is not electric. Controls, ignition, combustion-air equipment, safety devices, and the circulating blower may all depend on power.

That is very different from using electricity as the heat source.

If an existing fuel-burning furnace has an approved alternate-power connection and your generator or battery inverter meets the furnace’s real requirements, restoring the furnace can make much better use of scarce backup electricity than running portable resistance heaters.

Do not size from a guessed “furnace wattage,” breaker size, or generic surge multiplier. The dedicated furnace power-outage guide explains how to find defensible load data, and the transfer-switch guide covers connection concepts without turning them into a DIY wiring tutorial.

Electric furnaces, baseboards, and heat pumps are a different scale

An electric resistance furnace or baseboard uses electricity as the heat source. That moves the backup problem from hundreds of watts of controls/blower load into kilowatts of heating load.

Heat pumps can also be large 240 V loads, and auxiliary resistance heat can add much more demand. The thermostat label Emergency Heat is a separate HVAC operating mode; it does not mean the home has off-grid emergency heating. During a grid outage, that setting still needs electricity.

Use exact equipment data for any whole-system backup plan. Do not assume a consumer power station or small portable generator can run central electric heat.

Will a gas fireplace work during a power outage?

Sometimes, and this is one of the more useful existing-home options.

Natural Resources Canada notes that some homeowners choose gas fireplaces with a continuous pilot because they can provide auxiliary heat without electricity, while some electronic-ignition models include battery backup for power failures. See NRCan’s current gas fireplace guidance.

But the exact model matters. A fireplace can have:

• a standing pilot and millivolt control,
• electronic ignition with battery backup,
• an AC blower that stops while the burner still works,
• or powered venting/interlocks that prevent burner operation without electricity.

Check the manual. Do not bypass powered venting or safety controls just because the gas supply is still available.

What about a wood stove or open fireplace?

An existing, properly installed and maintained wood stove can provide substantial heat without grid electricity. It is real off-grid heating infrastructure, not something to improvise after the lights go out.

An open masonry fireplace is different. Natural Resources Canada says many open-hearth fireplaces cannot make up for the house air they draw up the chimney and therefore provide little or no net whole-house heat gain. They can still feel warm directly in front of the fire while increasing heat loss elsewhere. See NRCan’s Keeping the Heat In guidance.

If you rely on wood heat, chimney condition, clearances, dry fuel, alarms, and normal operating procedures remain non-negotiable during an outage.

Can I use a propane heater indoors in Canada?

Only if the exact Canadian appliance instructions and applicable local rules permit the intended indoor use. Do not infer that from the words “propane heater.”

Health Canada’s general CO guidance says never to use kerosene, propane, or oil space heaters in enclosed areas unless they are specifically designed for indoor use. That wording is important because it is not permission for every portable heater. See Health Canada’s CO prevention guidance.

A useful real-world example is the popular Mr. Heater Portable Buddy. The manufacturer’s Canada version is currently described as an outdoor portable radiant propane heater and lists “Indoor safe: No.” Mr. Heater’s own Buddy-series Canadian guidance says unvented heaters are prohibited from indoor use in Canada. The Canadian manual warns against using the appliance in an enclosed space such as a home. See the Canada-version product page and manufacturer Buddy-series guidance.

That is exactly why a U.S. product page, an oxygen-depletion sensor, a retailer category, or a generic “CSA certified” badge is not enough to establish residential indoor use in Canada.

A CO alarm does not make prohibited use safe

A carbon monoxide alarm is essential protection in a home with fuel-burning equipment. It is not an air-quality meter and it does not override the appliance manual.

Health Canada explicitly says CO alarms are not a substitute for proper installation and maintenance of fuel-burning appliances. If an alarm sounds, leave immediately and call emergency services from outside.

Use ReadyHome’s carbon monoxide detector guide for placement and alarm maintenance.

What should never be used to heat the house?

These are not emergency-heating hacks:

• barbecue or charcoal grill indoors
• camping stove or portable burner indoors
• outdoor patio heater indoors
• construction heater not approved for the space
• fuel-burning generator indoors, in a garage, basement, crawlspace, shed, or covered area
• gas range or oven used as a space heater
• vehicle idling in a garage, even with the garage door open

Canada.ca’s current power-outage guidance says a natural-gas stove may be used for cooking during an outage but not as a heating source, and it repeats the prohibition on outdoor fuel-burning cooking equipment indoors.

Candles and flowerpot “heaters” are not useful substitutes either. A pot can change how a candle’s small amount of heat is distributed; it cannot multiply the energy released by the candle. You add open-flame fire risk without creating a serious room heater.

Build one practical warm zone

If whole-home heat cannot be restored, reduce the amount of space you are trying to make comfortable.

A reasonable warm-zone plan is:

1. Choose a room people can actually occupy safely. Prefer a room that is easy to close off and does not force you to block required ventilation, appliance combustion air, exits, or smoke/CO alarm coverage.
2. Close doors to unused areas. You are trying to avoid heating every room equally.
3. Reduce obvious drafts. Close exterior doors, use existing curtains or blinds, and address simple door-bottom leakage without permanently blocking ventilation paths.
4. Insulate people from cold surfaces. Dry socks, slippers, rugs, camping pads, blankets, and layered clothing can improve comfort without consuming stored electricity.
5. Use solar gain when it helps. Let sun into the occupied room during the day, then close window coverings after sunset.
6. Use personal electrical warming selectively. Spend limited battery Wh where it meaningfully improves comfort.
7. Keep monitoring the rest of the house. A warm room does not protect every pipe or building component.

For permanent draft reduction, use the weather-stripping and door-draft guide.

How long will a house stay warm with no power?

There is no responsible universal answer.

The cooling rate depends on:

• outdoor temperature,
• wind,
• air leakage,
• insulation,
• window area and performance,
• house shape and exposed surface area,
• thermal mass,
• sun,
• starting indoor temperature,
• basement and ground coupling,
• and internal heat from occupants and equipment.

A tight, well-insulated home and a drafty older home can behave very differently in the same weather. ReadyHome does not publish a “your house freezes in X hours” calculator because the missing inputs can make the answer dangerously convincing rather than useful.

What you can do is watch the actual indoor temperature trend, the people in the house, the outdoor conditions, and the systems that become vulnerable as the house cools.

Protect pipes separately from people

Do not keep someone in an unsafe home solely because you are trying to save the plumbing.

When whole-home heat cannot be maintained, move plumbing protection into its own plan. Exterior-wall piping, crawlspaces, garages, cabinets, and other exposed areas can cool differently from the occupied room.

Use the frozen-pipe guide for the current preparation and shutoff guidance rather than improvising a full-house drain-down from a generic outage article.

When should you leave for a heated location?

ReadyHome cannot declare a specific house safe from a webpage, and there is no single indoor temperature that applies to every household.

Canada.ca’s extreme-cold guidance says extreme cold can quickly become life-threatening and tells people to go to the nearest heated location at the first signs of cold exposure, such as numb extremities. Current federal power-outage guidance says to prepare to evacuate if the home becomes unsafe because of extreme cold or another hazard.

Your tolerance for waiting should be lower when:

• an infant, older adult, or someone with a relevant medical or mobility vulnerability is present;
• someone is becoming confused, unusually drowsy, clumsy, numb, or otherwise showing signs of cold exposure;
• required medical or accessibility equipment cannot be supported;
• you no longer have a safe heating method;
• severe weather is worsening and safe travel may become harder later;
• local authorities advise evacuation or open warming/reception centres.

If there is an immediate medical emergency, call 911. Do not wait for a thermometer to cross a ReadyHome-made number.

Emergency Heat Planner

Use this as a decision router, not a safety certification. It deliberately refuses to turn vague inputs into a numeric safety score.

1. What normally heats your home?Natural-gas furnacePropane furnaceOil furnaceElectric resistance furnaceHeat pumpElectric baseboardInstalled wood stoveGas fireplacePellet stoveOther / not sure

2. What backup electricity is available?NonePortable power station / battery inverterPortable generatorInstalled standby generator / battery

3. What portable option are you considering?None / show me the best directionHeated blanket, pad, or heated clothingElectric space heaterPortable propane / camping heaterOutdoor patio, construction, BBQ, or camping applianceGas range or oven

Outdoor conditionsCool, but above freezingBelow freezingSevere / extreme cold

Expected outageA few hoursOvernight / up to a dayMulti-dayUnknown

Someone needs extra cold protection. This can include infants, older adults, people with relevant health conditions, or anyone who cannot reliably keep themselves warm.

Your estimate

Planner verdict

Build a warm zone and preserve options instead of chasing whole-home portable heat.

Close off unused rooms, reduce obvious drafts without blocking required ventilation, use dry layers and bedding, and direct limited electrical energy to the people who need it most. Keep a heated relocation option ready if conditions worsen.

What to do next

1. Choose one practical occupied room.
2. Reduce avoidable heat loss at doors and windows.
3. Use low-power personal warming if available.
4. Protect vulnerable plumbing separately.
5. Follow local alerts and move to a heated location if the home or occupants are becoming unsafe.

Reduce heat lossProtect frozen-pipe risks

Minimum, better, and overkill

Minimum viable winter-outage plan

• working smoke and CO alarms with backup power where required;
• flashlights and charged phone/power banks;
• dry layers, blankets, sleeping bags or other non-electric warmth;
• a known one-room warm-zone plan;
• knowledge of what normally heats the home and whether it needs electricity;
• a heated place you could relocate to if the home becomes unsafe;
• a separate frozen-pipe plan.

Better

Add the backup system that matches your actual house:

• an approved furnace backup-power arrangement for a fuel-burning furnace;
• a properly sized portable power station for lower-wattage priority loads;
• an installed wood stove or outage-capable gas fireplace if that already fits the home;
• enough generator fuel for a realistic outage plan, stored and handled safely;
• low-power personal warming equipment where appropriate.

Overkill for most households

Buying enough portable lithium battery capacity specifically to run one or more 1,500 W resistance heaters for a long winter outage is technically possible, but it is usually an expensive way to solve the heating problem. If you are considering many kilowatt-hours of storage for space heat, compare that plan with powering the existing heating system, improving the building envelope, or installing purpose-built backup heat first.

Frequently asked questions

Is there a real battery operated heater for a power outage?

There are real battery-powered warming products, but battery size limits the heat they can deliver. Small rechargeable products are much more plausible as hand warmers, heated clothing, or local personal warmers than as substitutes for a 1,500 W room heater. Check watt-hours, not just mAh or marketing language.

Can a 1,000 Wh power station run a 1,500 W heater?

Only if its inverter supports that continuous load. Using an illustrative 85% delivered-energy assumption, 1,000 Wh would provide about 850 Wh to the AC load, or roughly 34 minutes at 1,500 W if the heater ran continuously. Real results vary. Use the runtime calculator with your actual equipment.

Is an oil-filled radiator better on a battery than a ceramic heater?

Not automatically. If both are drawing the same electrical wattage for the same amount of time, they use the same amount of battery energy. Their heat distribution, thermostat cycling, surface temperature, noise, and comfort can differ, but there is no battery-energy loophole that lets a 1,500 W resistance radiator consume only a fraction of 1,500 W while energized.

Can I run an electric space heater from a generator?

Potentially, but there is an important connection catch. Health Canada says never plug a portable electric heater into an extension cord or power bar. That means the casual setup of an outdoor generator, a long extension cord, and an indoor 1,500 W heater is not ReadyHome’s recommendation.

If a generator supplies normal household circuits through approved transfer equipment, an indoor heater may be one load to size for. It is still a large continuous load, so compare it with powering an existing fuel-burning furnace or using lower-power personal warming before dedicating scarce generator capacity and fuel to resistance heat.

Can I use a Mr. Heater Buddy indoors in Canada?

Do not apply U.S. Buddy guidance to a Canadian unit. Mr. Heater’s current Canada-version MH9BX page lists Indoor safe: No, and the manufacturer’s Canadian Buddy guidance says unvented heaters are prohibited from indoor use in Canada. Follow the exact Canadian model/manual you own.

Can I use a gas fireplace when the power is out?

Some can. Natural Resources Canada notes that continuous-pilot fireplaces can provide heat without electricity and that some electronic-start models use battery backup. Power-vented and other designs may still require electricity. Check your exact manual.

How cold is too cold to stay in the house?

There is no universal ReadyHome number. Watch actual occupants, indoor conditions, outdoor weather, local emergency guidance, and whether you still have a safe way to maintain warmth. Move to a heated location when the home or the people in it are becoming unsafe rather than waiting for an invented threshold.

Methodology and sources

Methodology

This page was built from September 2026 Canadian search-demand research and a technical research dossier, then independently checked against current federal guidance and first-party manufacturer documentation. We kept the dossier’s useful energy and building-science framework but rejected several claims that were too absolute to publish, including universal indoor-temperature evacuation thresholds and blanket propane rules that did not preserve appliance- and jurisdiction-specific nuance.

Primary current references used for the safety boundaries on this page include:

• Canada.ca: Power outages
• Canada.ca: Extreme cold
• Canada.ca: Winter storms
• Health Canada: Preventing carbon monoxide exposure
• Health Canada: Electrical product safety
• Natural Resources Canada: Gas fireplaces
• Natural Resources Canada: Keeping the Heat In
• Mr. Heater: Portable Buddy Canada version
• Mr. Heater: Buddy-series Canadian guidance

The battery-runtime table is illustrative engineering math, not manufacturer performance data. It assumes 85% of nominal battery watt-hours reach the AC load and states that assumption beside the calculation.