Friday, June 29, 2007

Fans vs. AC

Straight from Mr. Electricity himself:
A window unit AC uses 500 to 1440 watts, while a 2.5-ton central system uses about 3500 watts. That's a lot of energy. A floor fan uses only 100 watts on the highest speed, and ceiling fans use only 15 to 95 watts depending on speed and size.

Comment: Michael Bluejay, aka Mr. Electricity, runs a site devoted to saving electricity. Green Factoid has spent many happy hours on his site, literally spellbound by his wealth of technical data: the site can only be described as nirvana for the factoid loving.

As far as fans and ACs go, here are a few numbers. We currently pay about $.18/kWh. So a single 1000w air-conditioner costs the seemingly low $.18/ hour. Running that AC 24/7, however, would cost us a not-so-modest $130/month. Using the same numbers, with central, you will pay $.63/hour and $453/month.

While no one but my father runs their AC round the clock (and his is central!), in our profligate days we would often run three ACs at a time to cool our apartment. That could easily add up to more than 24/7 use in July and August, especially since I work at home during those months.

One the other hand, running a 100 watt fan for the same period costs less than .02/hour and a whopping $13/month. Ceiling fans are even less.

1 comment:

Anonymous said...

Great blog. When buying an air conditioner, you should also look at the EER. Sometimes it is worth paying more for an air conditioner with a higher EER because you save money on electricity.