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In 2021, southern and midwestern states in the U.S. experienced huge rolling blackouts as a result of the severe Winter Storm Uri. Ice knocked out power lines in states like Louisiana and Mississippi, for example, while in Texas, more than 2.7 million Texans went without power as rare frigid temperatures combined with unprecedented surges in electricity demand to trigger a state of emergency.
In response, utilities in these states are urged residents to turn down the heat in order to keep their power grids up. But wait: How does lowering your thermostat keep your lights and heat on? Let’s consider the science.
How to Stay Warm Without Using So Much Energy
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If your home still has power in an emergency, it seems like something you’re free to use that isn’t hurting anything. But during a freeze, the grid may be running at very low capacity because of frozen infrastructure. That means the total amount of power for everyone is way lower at a time when winter demand is at its highest ... ever.
Central heat uses energy to physically blow air around your home, but most central heating systems rely on burning natural gas as the actual “heat.” Home appliances like your dryer and dishwasher—and, critically, heat blankets and space heaters—use power-hungry electrical resistors to generate heat.
That means central heat is actually a little better for energy, but all energy costs are high during a cold weather emergency. So if you live in an affected area, you should lower your energy use as much as you can.
This advice will sound ridiculously simple, but it’s the most scientifically—and economically—sound: Lower your thermostat (utilities recommend the mid 60s), layer up in warm clothes, and pile on traditional no-tech blankets. Plus, you should follow these other low-cost warmth hacks:
🔥 Stay upstairs.
Heated air expands and loses density. Thus, it rises. Upstairs will be warmer than downstairs, all things being equal.
🔥 Choose the right materials.
Thick materials have a higher R value (resistance to heat flow) than thinner materials and air-trapping materials like fleece, wool, and flannels are better still. The microscopic air pockets formed in these materials are poor conductors of heat, increasing the R value of the material. It’s the same concept with the fiberglass insulation in your walls and ceilings. It’s the air pockets that make the difference.
🔥 Avoid the “Cold 70 Effect.”
Exterior walls, windows, and cold floors may be as warm as 70 degrees Fahrenheit, but the thermodynamics are not working in your favor. Your body’s temperature of 98.6 degrees radiates heat to these cold surfaces, making you feel cold in the process. This phenomenon is known as the “Cold 70 Effect” and explains why you can feel cold even in a 70-degree room.
There are several things you can do:
Avoid: The farther you get from cold surfaces, the better.
Insulate:Warm slippers are better than socks and certainly better than bare feet. Again, thicker slippers that cover the entire foot have a better R value. And like your feet, your hands are nerve-rich surfaces. Keeping them warmer helps you feel warmer in general.
Duck and cover: When you can’t avoid the Cold 70 Effect, cover your head and neck with a hooded sweatshirt, especially a fleece product.
Another good choice is a sleeved or hooded blanket. Head and neck coverage is important. Increasing R value in these regions is good thermodynamics, but it’s also perception. Your head and neck are among the most cold-sensitive parts of your body. Feeling warmer mutes the body’s response to shiver, and you’ll feel more comfortable.