How Long Will a House Stay Warm Without Power?

Wintertime winter background thermometer snow on.

When the power goes out in the winter, the clock starts ticking. How long will a house stay warm without power? It’s a straightforward question, but the answer depends upon several factors, which we’ll explore in this guide.

Winter power outages present distinct challenges, such as how to stay warm without electricity. Practical preparation and knowledge are your allies in ensuring your home remains a refuge of warmth during an outage, and we’re here to equip you with both.

The average home will stay warm for 8-12 hours after the power goes out. After the first 8-12 hours, most homes will experience a gradual cooling over the course of the next couple of days. These figures will vary based on factors including the temperature outdoors, the configuration and construction of your home, and even how many people currently reside in the house.

Homeowners can help preserve the temperature of their homes during a power outage by purchasing home upgrades in advance of the winter storm season and taking practical steps to conserve heat during an outage. The choices you make during an outage will affect how long the house will stay warm without power.

Factors that Affect How Long a House Will Stay Warm Without Power

How long will a house stay warm without power? While the average home retains heat for 8-12 hours, let’s take a closer look at the factors that play into this equation. Some concern the construction of your home, while others take the external environment into account. Understanding these factors will equip you to better protect your family the next time the power grid lets you down.

The Type of House and Its Construction

How long the house will stay warm without power is greatly influenced by its construction. A brick house retains heat longer than one made of wood does, and a well-sealed, modern home could offer a few precious hours of warmth compared to what an older, draftier one might.

The Size of the House

The house's size and shape also impact how long the house will stay warm without power by providing some inherent structural insulation. A larger home has more internal air and surface area through which to lose heat than a smaller home does. A detached, multi-story home loses heat more rapidly than a single-level condominium attached on both sides does.

The Insulation in the House

The insulation of your home makes a significant impact on how long your house will stay warm without power. A well-insulated home retains heat far more effectively than a poorly insulated one does. Homeowners can now install better insulation than what was initially put in during construction. An insulation upgrade can improve energy efficiency and better protect families during a winter power outage.

The Temperature Outside

Of course, the outdoor temperature is an enormous factor in how quickly your home loses heat in a power outage. Extremely low temperatures outside can exponentially increase the rate of heat loss indoors. 

The Wind Speed

Wind can rapidly dissipate the stored heat in your home by exploiting any weaknesses in insulation or tiny gaps in the structure. When the wind speed is higher, it more quickly saps the warmth from your home.

How to Stay Warm Without Electricity

Now you know, on average, how long a house will stay warm without power and several factors that may affect it. However, heat preservation isn’t solely determined by structural and external conditions. Everything from how you utilize available resources to small shifts in your daily activities can help you conserve heat. Let’s explore how to stay warm without electricity.

Dress in Layers

Conserving your body heat is a priority when working to stay warm without electricity. Dressing in layers can help you achieve this. However, there’s no need to pile on several bulky sweaters. Multiple thinner layers, such as long-sleeved tee shirts, are more effective at trapping warm air close to your body. Multiple layers make it easier to adjust to regulate your body heat and prevent sweating, which may make you feel colder in the long term.

Use Blankets and Sleeping Bags

Senior couple covered blanket sitting beside.

Another tip for how to stay warm without power is to bundle up in blankets and sleeping bags. As with layered clothing, they trap warm air next to your body. Use them as portable, temporary personal insulation.

Stay Active

Physical activity is an essential way to keep warm when the power is out. Your body generates heat when you move, creating natural warmth you can use when the power grid fails. Engage in light, consistent activities such as walking around the house, doing mild exercises, or even light housework to boost your internal heat. Just be sure to pace yourself. You don’t know how long the outage will last.

Close Doors and Windows

In addition to closing the doors and windows to the outside, use towels to cut off drafts around or under them. Also, keep curtains shut unless the window brings in warm sunlight during the day. Also, don’t forget about interior doors. Closing them will help keep warm air in your living quarters.

Stay in One Room

A solid plan for how to stay warm without electricity involves both making new heat and conserving what you have. Gathering your family members and staying in a single room optimizes both strategies. Isolating activity to a single room helps to concentrate body heat, minimize the area that requires warming, and limit the avenues for heat loss. Choose a smaller, well-insulated room.

Use a Fireplace or Wood Stove

Young woman sitting home by fireplace.

If your home has a fireplace or wood stove, it can be an excellent heat source during a power outage. Have a supply of dry wood, kindling, newspaper, and matches or lighters available to use if the power goes out. All the standard safety concerns apply, so be sure to keep the flue clean and never leave the lit fireplace or stove unattended.

Things You Should Not Do to Stay Warm During a Power Outage

While figuring out how to stay warm without power is critical, it’s equally vital to recognize and avoid actions that compromise your safety. The following are things that you should not do to warm your home. Some seemingly attractive ideas are actually potentially fatal mistakes.

Do NOT Operate a Generator Indoors

Running a generator indoors might seem like a quick way to stay warm without power, but it is a deadly mistake. Generators produce carbon monoxide, a colorless, odorless gas that can quickly become lethal in enclosed spaces. Always use a generator outdoors, well away from windows and vents.

Do NOT Use a Gas Stove or Oven for Heat Indoors

Your gas stove or oven is engineered to be a cooking appliance, not a continuous heating source. While it’s safe for the time it takes to cook a meal, leaving it running for extended periods increases the risk of carbon monoxide buildup and fire. Always ensure good ventilation and never use these appliances solely for heating.

Do NOT Run Your Car Inside Your Garage

The heater inside your vehicle may be tempting, but running the car in an unventilated garage is a fatal mistake that may lead to carbon monoxide poisoning.

Do NOT Try to Warm Your House with Portable Stoves, Heaters, and Grills

Camp stoves, chimineas, gas-fired patio heaters, or charcoal grills produce heat, but they also release deadly carbon monoxide. Never operate a portable gas, charcoal, or wood-fired appliance indoors. These combustion appliances are only safe to use outside in the open air.

Do NOT Leave Candles Lit Unattended

Always blow out candles when going to sleep or leaving a room. The risk of an accidental fire is too great.

Do NOT Wait to Get Help

Reach out to friends and family who live outside the power outage zone or contact emergency personnel to locate a safe shelter. This is especially important for households with young or elderly family members.

Updates Designed to Keep Your House Warm Without Electricity

While storms may cause power outages at any time, how you prepare for them is within your control. How long your house will stay warm without power can be positively impacted by a few pragmatic updates, including the following:

  • Improve insulation.
  • Improve ventilation (to help regulate airflow and humidity).
  • Consider installing a whole-house generator.
  • Consider installing a backup battery or rooftop solar array to power your furnace or heater with your own electricity.

Related Topic: Carbon Monoxide Safety Checklist

How to Prepare for a Power Outage in the Winter

Make sure you have everything you need to follow our advice on how to stay warm if the power goes out. Store blankets, extra window coverings, and supplies for a wood-burning fire (if applicable) in a place that is easily accessed. Since layering up is a critical strategy for how to stay warm without power, keep plenty of clothes on hand, too.

Most outages only last a few hours, but some can last a week or more. So, in addition to knowing how to stay warm if the power goes out, you need to ensure your other needs are met as well.

According to the American Red Cross, you should store enough nonperishable food and water supplies for at least two weeks. Also, update your emergency first-aid kits and make sure all the medication for family members is available and in supply. Have enough flashlights, candles, and batteries to last at least two weeks. Keep everything together in an easy-to-access bin. While you will not likely need two weeks (or even two days) of supplies, having plenty on hand means that you will have peace of mind and can assist friends or neighbors.

Stay Warm and Safe During the Next Power Outage

Winter storms can be unpredictable and intense. Knowing how to stay warm without power is critical to the safety of you and your family. If the power goes out, it is vital that you follow the instructions of local officials.

In the meantime, contact your local Aire Serv® professionals for help preparing your home to ride out the winter, no matter what the weather throws at you. We offer comprehensive professional HVAC services to keep your home comfortable. We’re a proud member of the Neighborly community of home service companies, so the Neighborly Done Right Promise backs all our work, ensuring your satisfaction. Our experts are ready to assist with your HVAC needs and ensure your system works efficiently throughout the year.

There’s no guarantee you won’t experience a power outage this winter, but you can make sure your HVAC system is ready for it. Request an appointment today!