It turns out that most Americans been thinking about their home's energy use all wrong. A joint study from Columbia University, Ohio State University and Carnegie Mellon sought to survey the public perception of saving energy in the home, posing these three questions amongst their study: What uses more energy, room air conditioners or central air? Turning off the lights or switching to CFLs? Line-drying your clothes or changing the settings on your washer? We've got the answers!
Every bit helps, especially when it comes to saving energy. But could you actually save more by doing less?
It turns out the public is mostly wrong about what green moves save the most energy around the house. Here are three of the questions asked of study participants:
What saves more energy...
Room air conditioners or central air?
Participants in the study got this question half right, estimating that a central air conditioner uses around 1.3 times the energy of a room air conditioner. But the truth is that room units are way more efficient: Central A/C uses around 3.5 times as much energy as room A/C.
Turning off the lights or switching to CFLs?
Depending on how much you use your lights and how religious you are about turning them off, the answer to this question can vary wildly. But in the average household, switching to CFLs will save more energy than turning off the lights when you leave a room.
Line-drying your clothes or changing the settings on your washer?
The Department of Energy estimates the average energy consumption for a dryer to be around 3400 watt-hours. Changing your washer's setting from "hot/warm" to "warm/cold" saves around 4000 Wh, as mentioned by lead author Shahzeen Attari in response to a New York Times blog.
(Images: Think Green T-Shirt, JunkFoodClothing; laundry line, keelymariescott.com; clothespins on line, photos8.com)
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Once coal is converted to electricity it yields about 2,460 kWh/ton. This means that by doing both air drying and turning your settings from warm to cold you would be saving about three tons of coal!
Kinda awesome.
What confuses me about the last questions is that line drying and changing the settings on your washer are not mutually exclusive. Which one saves more energy is an interesting tidbit, but what saves more energy than either one (line drying or changing your washer settings) is both.
Scott, you're missing the little k in front of the Watt Hours. You only save 0.28% of a ton of coal or about 6 pounds of coal. Not an insignificant amount, but a lot less than three tons.
But if you have a room air conditioner in every room, I'd imagine you'd eventually tip the balance in favor of central air--unless I'm misunderstanding?
BombShell, the reason room specific A/C saves, is because you don't have to cool rooms you're not using.
I recently visited my uncle in Mexico, and room by room A/C was the standard. When we went to sleep at night, only the A/C units in the bedrooms were running, and during the day, the units in the bedrooms shut off, and the units in the living room and kitchen were running. They worked quite well.
In essence, there's no reason to cool 100% of your home all summer long.
Sure there is. A constant temperature with a central AC uses less energy than turning it off and having to recool the entire house again - especially when its over 95 outside.
a hot wash cycle is also used to kill bacteria etc. things that could be living in your towel you dry off with etc.
i agree with the above about the AC unit too. It seems like it would use more to have to cool and re-cool a room whenever you want to use it.
one summer i lived in an apartment and it was ungodly hot out and we had 1 AC unit in the bedroom. unfortunately i was trapped there because i didn't want to go anywhere else in the place. it was horrible and would probably never do that again.
it seems like the correct question would be to ask:
What uses less energy, utilizing a programmable thermostat with central air OR room based ac units?
this seems like a much better questions since they are both changing the ac based on use, if you are gone during the day or at night etc.
Jmorey,
I don't think your warm setting is hot enough to kill bacteria.
But it's hot enough to make us FEEL like we've killed bacteria, and that's the point, right? ;)