# Air Conditioners and Their Effect on my Electric Bill **URL:** \ **Category:** Factual Questions\ **Created:** [June 24, 2002, 7:18pm UTC](https://boards.straightdope.com/t/air-conditioners-and-their-effect-on-my-electric-bill/115762 "2002-06-24T19:18:10Z")\ **Posts on this page:** 18\ **Page:** 1
**Author:** ![audiobottle](https://avatars.discourse-cdn.com/v4/letter/a/bc8723/32.png) [@audiobottle](https://boards.straightdope.com/u/audiobottle)\ **Post date:** [June 24, 2002, 7:18pm UTC](https://boards.straightdope.com/t/air-conditioners-and-their-effect-on-my-electric-bill/115762/1 "2002-06-24T19:18:10Z")
It has become intolerably hot in my apartment, so I’ve been looking into buying an air conditioner. The actual price of the unit isn’t too bad ($125.00), but I’m concerned as to how much the electricity bill will go up. We’d probably just set it in the main room and turn it off when no one’s around (which is a large part of the day). Oh, yeah, right now we’re also running about 10 fans simulataneously, so presumably the air conditioner would take their place. So how much can I expect the electricity bill to go up? I’m looking for rough estimates… maybe a little more detail than just, “A lot” or “a ton,” although if everyone says, “You’ll go broke in three days” I’ll get the idea. Thanks. Audiobottle ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [June 24, 2002, 7:42pm UTC](https://boards.straightdope.com/t/air-conditioners-and-their-effect-on-my-electric-bill/115762/2 "2002-06-24T19:42:21Z")
If you look at your last electricity bill, it should tell you how much you’re being charged per kilowatt of electricity. The air conditioner’s box should indicate how much electricity it consumes (such indicators are also on other major appliances like fridges and freezers). Then it’s just a matter of doing the math. ---
**Author:** ![jacksen9](https://avatars.discourse-cdn.com/v4/letter/j/ce73a5/32.png) [@jacksen9](https://boards.straightdope.com/u/jacksen9)\ **Post date:** [June 24, 2002, 7:51pm UTC](https://boards.straightdope.com/t/air-conditioners-and-their-effect-on-my-electric-bill/115762/3 "2002-06-24T19:51:57Z")
Someone may be able to give you a good estimate if you provide this additional information: Average temperature during the time you plan to have your air conditioner on. Square footage or may better info could be cubic feet. If you have vaulted celings. a two story, etc… this would require your a/c to run more. Insulation - good or bad? The unit you buy should have something along the lines of an “energy rating”. I think that predicts how efficient your unit will be. Sorry I can’t answer your question, but I bet someone will if you can give this info. ---
**Author:** ![kirk](https://avatars.discourse-cdn.com/v4/letter/k/f9ae1b/32.png) [@kirk](https://boards.straightdope.com/u/kirk)\ **Post date:** [June 24, 2002, 7:55pm UTC](https://boards.straightdope.com/t/air-conditioners-and-their-effect-on-my-electric-bill/115762/4 "2002-06-24T19:55:03Z")
A general estimate is 50 cents to a dollar a day, depending on your electric rates. ---
**Author:** ![audiobottle](https://avatars.discourse-cdn.com/v4/letter/a/bc8723/32.png) [@audiobottle](https://boards.straightdope.com/u/audiobottle)\ **Post date:** [June 24, 2002, 8:03pm UTC](https://boards.straightdope.com/t/air-conditioners-and-their-effect-on-my-electric-bill/115762/5 "2002-06-24T20:03:45Z")
Thanks a lot… I’ll just go ahead and do the math, as I’m too lazy to measure out my room anyway. I don’t know why I never thought to do it that way myself. Thanks again! Audiobottle ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [June 24, 2002, 8:11pm UTC](https://boards.straightdope.com/t/air-conditioners-and-their-effect-on-my-electric-bill/115762/6 "2002-06-24T20:11:43Z")
By way of comparison, here is an extract from a sample [Electricity Consumption Score Card](http://www.ianr.unl.edu/pubs/consumered/heg94.htm) ```auto Appliance Average Average Hours Est. KWH Cost per Year Wattage per year Used/Year (at 4 cents) Air Conditioner* 860 1000 860 34.40 Air Conditioner* 3,750 1000 3750 150.00 Dehumidifier 257 1467 377 15.08 Fan, Attic 370 786 291 11.64 Fan, Circulating 88 489 43 1.72 Fan, Rollaway 171 807 138 5.52 Fan, Window 200 850 170 6.80 ``` The 1000 hours for air conditioner use is an estimate and will vary based on your local climate. A single-room model at 860W will be considerably cheaper than a full-house 3,750W monster. Fans are much less expensive, but if they aren’t doing the job, what good are they? If you set up a small $150 unit to cool a specific room or rooms, it is crucial that you maximize efficiency. Keep the unit as clean as possible (as specificed by your manual) and keep extraneous doors and windows closed tightly. My own AC is rigged up at my back porch. My flat is mostly open, but even then I always make sure my bathroom, vestibule and basement doors are kept closed when the AC is on. There’s no point cooling areas I’m not using. ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [June 24, 2002, 8:21pm UTC](https://boards.straightdope.com/t/air-conditioners-and-their-effect-on-my-electric-bill/115762/7 "2002-06-24T20:21:02Z")
As a side note, I strongly recommend replacing incadescent light bulbs with flourescents, starting with the rooms you want to cool. The amount of energy saved by switching bulbs may be small, but incandescents generate a lot of heat and there’s no point making your AC work harder. Superhot halogen bulbs should be used only when necessary while the AC is on, if at all. With a little bit of effort at making your living space more heat-efficient, you can get and run a good AC at not a lot of expense. Running ceiling fans at the same time as your AC will help circulate the cooler air. I suggest running the fans intermittently for a few minutes at time while the AC is on. ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [June 24, 2002, 9:35pm UTC](https://boards.straightdope.com/t/air-conditioners-and-their-effect-on-my-electric-bill/115762/8 "2002-06-24T21:35:12Z")
I installed central air about 1 year ago and was dreading the electric bill. Due to estimated meter readings The ‘big’ bill didn’t come the 1st month. Then the 2nd month came and I got the bill - I saw really no noticeable difference. > [@](#): > > Superhot halogen bulbs should be used only when necessary while the AC is on, But if you replace a 60 watt (standard) bulb with a 40 watt halogen you should be producing less heat and getting the same amount of light, a compact floresent would use around 15-16 watts btw. ---
**Author:** ![SmackFu](https://avatars.discourse-cdn.com/v4/letter/s/53a042/32.png) [@SmackFu](https://boards.straightdope.com/u/SmackFu)\ **Post date:** [June 25, 2002, 12:06am UTC](https://boards.straightdope.com/t/air-conditioners-and-their-effect-on-my-electric-bill/115762/9 "2002-06-25T00:06:28Z")
I think **Bryan** ’s referring to 300 W halogens like I have in my torchiere, not 40 W ones. ---
**Author:** ![Boo\_Boo\_Foo](https://avatars.discourse-cdn.com/v4/letter/b/e274bd/32.png) [@Boo\_Boo\_Foo](https://boards.straightdope.com/u/Boo_Boo_Foo)\ **Post date:** [June 25, 2002, 12:58am UTC](https://boards.straightdope.com/t/air-conditioners-and-their-effect-on-my-electric-bill/115762/10 "2002-06-25T00:58:17Z")
Forgive a potential hijack here: But it is interesting for mine that in the above consumption listing, air conditioning by far consumes the most amperage. This reminds me of an observation I once read which tellingly seems to be ringing more and more true - namely “If anything about homosapiens the species will be their downfall, it is there insistance on adapting their environment to THEIR needs, unlike the rest of the animal kingdom which is quite content to adapt itself to it’s surrounding environment”. AN interesting thought to ponder, yes? ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [June 25, 2002, 1:21am UTC](https://boards.straightdope.com/t/air-conditioners-and-their-effect-on-my-electric-bill/115762/11 "2002-06-25T01:21:43Z")
The “above consumption listing” was specifically for appliances related to “Comfort/Conditioning”. I selected extracts that were relevant to the question at hand. The linked site also had a “Food Preparation” table, on which “Range with oven” is listed as having an average wattage of 12,200W and the “Laundry” table cites a Clothes Dryer with 4856W. What’s your point, aside from taking an opportunity to try to act smug and pretentious? And yes, I was referring to 300W halogens, though I’ve seen some bulbs that are 500W. The power consumption isn’t as relevant to the issue of getting an AC as the amount of heat the bulbs generate, which is considerable and will only work against an air conditioner. ---
**Author:** ![elmwood](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/elmwood/32/3060_2.png) [@elmwood](https://boards.straightdope.com/u/elmwood)\ **Post date:** [June 25, 2002, 1:26am UTC](https://boards.straightdope.com/t/air-conditioners-and-their-effect-on-my-electric-bill/115762/12 "2002-06-25T01:26:57Z")
My last electric bill was $250. That’s for cooling a 1,900 square foot house down to 74 degrees through June in central Florida. Not good. ---
**Author:** ![Boo\_Boo\_Foo](https://avatars.discourse-cdn.com/v4/letter/b/e274bd/32.png) [@Boo\_Boo\_Foo](https://boards.straightdope.com/u/Boo_Boo_Foo)\ **Post date:** [June 25, 2002, 2:58am UTC](https://boards.straightdope.com/t/air-conditioners-and-their-effect-on-my-electric-bill/115762/13 "2002-06-25T02:58:41Z")
> [@](#): > > \*Originally posted by Bryan Ekers \* > \*\*What’s your point, aside from taking an opportunity to try to act smug and pretentious? > \*\* Please, Bryan, be mellow my friend. I never meant anything smug or pretentious in my post - I merely wished to point out that human beings like to adapt their environment to suit them, and not the other way around. Most importantly of all Bryan, I was thankful and appreciative of your list. It served to illuminate me on the relative costs involved in keeping a room cooler than the prevailing outside ambient temperature. Please accept my apology for overstepping the mark… ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [June 25, 2002, 12:04pm UTC](https://boards.straightdope.com/t/air-conditioners-and-their-effect-on-my-electric-bill/115762/14 "2002-06-25T12:04:50Z")
**elmwood** I for some silly reason thought electricty was cheap in FL and you people got socked in your water bill. Anyway a $125 A/C is not going to be that powerful and shouldn’t make that much difference. I would estimate on $20/month. ---
**Author:** ![Running\_with\_Scissors](https://avatars.discourse-cdn.com/v4/letter/r/a183cd/32.png) [@Running\_with\_Scissors](https://boards.straightdope.com/u/Running_with_Scissors)\ **Post date:** [June 25, 2002, 2:08pm UTC](https://boards.straightdope.com/t/air-conditioners-and-their-effect-on-my-electric-bill/115762/15 "2002-06-25T14:08:28Z")
> [@](#): > > \*Originally posted by k2dave \* > \*\*I installed central air about 1 year ago and was dreading the electric bill. Due to estimated meter readings The ‘big’ bill didn’t come the 1st month. Then the 2nd month came and I got the bill - I saw really no noticeable difference. Yes, but if you were formerly using window ACs, you’re going to a more efficient system. Of course, now you may be cooling rooms that you weren’t cooling before, which could be why it’s a wash. ---
**Author:** ![Nightsong](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nightsong/32/3083_2.png) [@Nightsong](https://boards.straightdope.com/u/Nightsong)\ **Post date:** [June 25, 2002, 4:00pm UTC](https://boards.straightdope.com/t/air-conditioners-and-their-effect-on-my-electric-bill/115762/16 "2002-06-25T16:00:13Z")
Another factor that comes into play is how cold you want to try and get the room. Generally, the ‘warmer’ you set the controls at, relative to the outside temperature, the less money it will cost. (Thus **elmwood** ’s huge bill: 74 degrees for a relatively decent sized home, in Flordia. I would have expected a fairly sizeable bill, unless his home was really well insulated and designed around maximum A/C efficency.) In my experience, there’s usually a ‘balance point’: a setting that will keep the house cool enough for your needs, yet will have the A/C unit run the least amount of time. (Does this make sense? If not, I’ll try to clarify.) This balance point will vary depending on how good your insulation is, what the temp is outside, etc., etc., etc. In the house I’m currently at, this temperature is actually at 80 degrees (F). It’s still nice and cool in the house (about 77 or so), while it’s been generally in the 90’s outside. * * * \<\< Like cool, daddy-o. \>\> ---
**Author:** ![CurtC](https://avatars.discourse-cdn.com/v4/letter/c/ce73a5/32.png) [@CurtC](https://boards.straightdope.com/u/CurtC)\ **Post date:** [June 25, 2002, 4:10pm UTC](https://boards.straightdope.com/t/air-conditioners-and-their-effect-on-my-electric-bill/115762/17 "2002-06-25T16:10:55Z")
The fans you’re running not only increase your light bill, but they also heat up the rooms. Only use a fan that’s actually blowing on you, to make you feel cooler. A fan that’s running in a room with no people in it is counter-productive. ---
**Author:** ![handy](https://avatars.discourse-cdn.com/v4/letter/h/b5a626/32.png) [@handy](https://boards.straightdope.com/u/handy)\ **Post date:** [June 26, 2002, 3:47pm UTC](https://boards.straightdope.com/t/air-conditioners-and-their-effect-on-my-electric-bill/115762/18 "2002-06-26T15:47:39Z")
Yeah & make sure the fans are going the right direction. One direction makes the room warmer & one cooler, thats for ceiling fans though.