February 23, 2019

Caring for Creation: October Green Tip

Should I Reheat My Home or Keep it Warm?


Hey Mr. Green,

In your book, Hey Mr. Green, you say that it takes more energy to maintain a constant temperature at home than to lower the heat at night and crank it back up in the morning. My neighbor claims that keeping a constant warm temperature is better because reheating takes more energy. What’s the truth?

I stand by all of my book’s myriad words of wisdom—

But to your question: Maintain a constant indoor temperature and you’re heating not just your home but also the great outdoors. Heat is constantly lost, especially through doors and windows; the warmer it remains inside, the more heat escapes. It’s a law of thermodynamics, the same principle that makes tank water heaters less efficient than on-demand models.

This is why it takes less energy to reheat a house in a short time than to keep it warm all the time, and why energy-conservation organizations like the American Council for an Energy-Efficient Economy estimate a 2% savings on heating bills for each degree you lower the thermostat for eight hours at a time.

(Mr. Green is Bob Schildgen – a columnist for Sierra Magazine and has a book titled “Hey Mr. Green” published in 2008)



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