How Fast Should Temperature Drop In a House?

Learn how much time your home needs to get cold when the electricity is off

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When the power goes out in your house in winter, the worst nightmare for any homeowner would be the lowering of the temperature indoors. 

When it’s nearly the same cold inside as it’s outside, staying home is no longer pleasant!

No wonder many people ask: how long will the house stay warm without heat? And today, we will tell you more about that issue. Read on to find out how fast the temperature will drop in your house when the power is off. 

Also, we will explain what factors influence the temperature levels in your house and how you can stay warm while the issue is being solved.

To the old house after the snowfall
By vista.com

How Fast WIll Temperature Drop In a House With No Heat?

How long can a house go without heat? This is one of the questions homeowners ask when they face a power outage for the first time. If your power goes out in cold weather or you lose your heat source, note that your house will start to cool immediately! 

On average, it takes about 18 minutes to cool down a house by 1 degree. Of course, depending on a particular home, a 1-degree drop can happen in 12 minutes, and in other houses, it will take longer. What you should know is that, in general, your house can remain warm for 8 to 12 hours. If it is well-protected and insulated, it will keep the indoor temperature above 0° F for one day to many weeks.

How cold will a house get without heat? To calculate the approximate temperature, here is a chart for you. It will show you how long it should take to cool down a house from different initial temperatures.

From/To75°F80°F85°F90°F95°F
65°F180 min.240 min.360 min.450 min.540 min.
68°F126 min.216 min.306 min.396 min.486 min.
70°F90 min.180 min.270 min.360 min.450 min.
72°F52 min.144 min.234 min.324 min.414 min.
75°F0 min.90 min.180 min.270 min.360 min.
78°FN/A36 min.126 min.216 min.306 min.

Now you can approximately imagine how fast your home will get colder should a power outage occur.

Factors That Can Affect Your Home Warmth

As you already know, each house will get colder gradually, but some of them will lose heat faster whilst others will get colder slower. But what does it depend on, you may wonder? There are several factors that can influence the speed of heat loss.  

  • Outside air temperature The colder it is outside, the faster your home will get cold.
  • Inside air temperature. The warmer it is indoors compared to the outside, the faster your home will cool down. Sometimes, you could lose 15° F overnight!
  • Wind speed matters. If your home is poorly insulated, the wind will speed up heat loss!
  • A basement or crawl space can slow down the cooling of your home since the ground is warmer under and around your house.
  • Size of your air conditioning systems. If you have an oversized unit, a 1-degree temperature drop happens in less than 18 minutes. If you have an undersized unit, the 1-degree temperature drop will take more than 18 minutes.
  • Insulation.
  • Size of your home. Bigger houses usually take longer to drop the indoor temperature. In smaller houses, you can see a faster change in temperature.

Now that you know what factors influence temperature lowering and heat loss in your house, you can decide what to consider and what to pay attention to for preparing your home for a possible power outage.

What to Do to Stay Warm In a House With No Heat

If a power outage has already happened and you feel that your house is slowly getting colder hour by hour, it is essential to take a few measures to keep yourself and your family members warm for as long as possible. Below, you can find a list of tips and recommendations that will help you stay warm and cozy even if the house is already cold enough.

  • Dress in layers. If possible, put on a wicking layer underneath to move moisture away from your body and keep you from getting cold. For a wicking layer, use wool, polyester, polyethylene, or microfiber.
  • Avoid wearing cotton. Once the cotton is wet, it no longer provides insulation to the body.
  • Cover your head with a stocking cap or beanie to avoid losing body heat through your noggin.
  • Wear woolen socks to keep your feet warm.
  • Cover your hands with mittens, not gloves, since hands stay warmer when your fingers are together.
  • Cover your neck and face with a scarf or a balaclava.
  • Use chemical, hand, and foot warmers if you have them.
  • Choose a room to keep warm. Shut the door and hang blankets in the openings to keep warmth inside.
  • Cover windows with cardboard, old newspaper, bubble wrap, or blankets to eliminate drafts.
  • Use towels, old blankets, or rugs to cover cracks at the bottom of the door and window sills.
  • Don’t open doors unless necessary since open doors allow cold air in.
  • Get enough high-energy, no-cook foods, e.g., granola bars, nuts, nut butter, trail mix, cheese, beef jerky, dried meat sticks, or freeze-dried backpack meals.
  • Warm drinks like ginger tea or regular tea will warm you from the inside out. Good choices are also broth cubes, hot cocoa, and coffee.

Now you know what to do and what to eat/drink to stay warm when your house has experienced a power outage and gets cold. With these simple tips, you will comfortably wait until the problem is fixed, and you can enjoy your cozy and warm home again!

Safety Measures to Take When There Is No Heat In Your House

When your power is off, and you feel you are freezing indoors, most of us would think about getting a propane stove to warm up some drinks or cook hot meals. But this is what you must never do inside a house! In addition, there are a few other restrictions you must follow to stay safe during a power outage.

  • Do not use propane camp stoves or outdoor grills inside the house or any enclosed space! They give off deadly carbon monoxide!
  • Avoid using oil and grease lamps since they can explode if not used correctly.
  • Unplug large appliances and electronics or turn off breakers. This way, they won’t get burned out if there is a power surge when the power goes back on.
  • Let faucets slow-drip to avoid freezing pipes.
  • Stay away from power lines hanging or lying on the ground. They may be hot or electrified.
  • Keep your car exhaust free and clear to avoid deadly carbon monoxide poisoning if you use your car’s power. Do not run it in an enclosed space, like a garage.
  • Cooking food indoors can be done safely in a wood fireplace, with canned heat, or with a backpacker-style alcohol stove.
  • If you use candles, place them in a jar and keep an eye on them. Open-flame light sources are a fire hazard!

Follow these simple precaution measures, and you can be sure you and your family members will stay safe during the power outage.

Handy Tips to Keep In Mind to Survive the Power Outage

The worst thing that can happen when the power goes off, and your house starts getting colder is to realize you haven’t got ready for that. People often say they had problems with light, drinking water, or food supplies during the outage just because they didn’t think about those in advance. So to help you avoid this scenario, here are a few helpful life hacks to keep in mind. 

  • If you have a garage, you should know how to raise and lower its electric door manually.
  • In case of frozen pipe bursts, know where your water valves are and how to shut them off.
  • Get necessary medications ready at hand.
  • During the winter, keep your vehicle’s gas tanks no lower than 2/3rd in case you need to start your car to get warm or charge something.
  • Ensure the car’s exhaust is free and clear and that you run the vehicle in an open, outdoor space.
  • Winterize your home before winter arrives.
  • Get an alternative heat source (woodburning stove, outdoor generator, etc.)
  • Make a 72-Hour Emergency Kit.
  • Fill your bathtub and sinks with water to flush the toilets. Do not drink this water unless you treat it or know it’s safe!
  • Get enough drinkable water to use for 72 hours.
  • Filter the water you are going to drink.
  • Prepare LED headlamps for hands-free tasks.
  • Get LED lights ready and ensure they are all fully charged.
  • Always keep power banks fully charged, just in case.
  • Get chem-lights ready since they can last up to 12 hours.

These recommendations will help you get all the necessary stuff ready long before the outage occurs. This way, you will be fully prepared for the no-light-and-heat time and will even be able to spend it cozily!

Now you know how fast the temperature might fall in your house if a power outage occurs or if you lose the source of energy. But with the help of the tips and life hacks we shared with you today, you will not only know how to keep yourself warm. You will also be able to enjoy warm drinks and hot meals and have light because we told you what devices and appliances you should prepare in advance.

Links on this topic to authoritative sources:
  1. Building insulation : https://en.wikipedia.org/wiki/Building_insulation
  2. Where to Insulate in a Home : https://www.energy.gov/energysaver/where-insulate-home

Frequently Asked Questions

Will A Small House Get Cold Faster Than A Big One?

Yes, in smaller houses, air temperature changes will be seen faster.

Can Cold Air Get Into The House Through The Chimney?

Yes, it can, especially on a windy day!

Does Room Size Affect Temperature?

The temperature in a smaller room will increase more rapidly than in a larger room because there is less air to transfer heat to it from outside. 

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