Conclusion: BUSTED.
The idea is that turning down your thermostat when you leave the house ultimately uses more energy because the furnace has to work extra hard to make the house warm again once you turn it back up.
Truth: Don’t be left out in the cold on this myth, because it isn’t true. According to Conservation Consultants Inc., the energy used to reheat a space is always less than or equal to the amount of energy used to keep it at a consistent higher temperature.Your home is much more resistant to heat loss than you may think; furniture and carpeting retain enough heat so that your furnace will not have to work that hard to heat a room back up to a comfortable temperature.
Have a friend who swears turning off the light when you leave a room actually wastes energy? Does your uncle tell you Hummers are more eco-friendly than hybrids? Whatever the eco myth, we'll help you get to the bottom of it. Submit your myth to SustainLane Greenbusters.
Jimi D. says:
Does this apply to air conditioning as well? The heat that is absorbed by the furniture and carpeting is believed to make the A/C work longer to cool the house. Can you verify?
Thanks.
Emmett P. says:
Yes, it applies to air conditioning as well. The math is exactly the same.
Bryce SL N. says:
Right conclusion, wrong reasoning. It has nothing to do with carpets and furniture. Your house is "leaky", just like a bucket with a hole near the bottom. The cooler the house, the less quickly it "leaks" heat. It takes less energy to "fill the house back up with heat", compared to keeping the leaky house "full all the time". Do the experiment with water in a leaky bucket, the results are the same as with a house.
In fact if your house was perfectly insulated, turning the heat off would not save energy. Note that "superinsulated" houses do exist, and they can get by, even in cold climates, with no heater at all.
Diana Budds says:
Innovative design is key to energy efficiency. Passive heating and cooling is one way that architects can design homes so that they maximize resource use. Check out this article: http://www.nytimes.com/2008/12/27/world/europe/27house.html?_r=1&scp=2&sq=germany%20air%20house&st=cse