some like it hotter than i like it

July 3, 2006 12:37 PM

Is there such a thing as an inexpensive, battery-powered air conditioner?

I'm renting a room in a 100 year-old house, and the landlady will not let me use an air conditioner because the circuits are old, and she is convinced that if I plug in an air conditioner 'the whole house will burn down.'

She expressed a willingness to have an electrician come and evaluate the job, and I have posted an ad on craigslist and responded to some ads on craigslist, but between the flaky electricians who have answered and my landlady's unwillingness to pay much, we haven't yet made a deal. Summer is dragging on and it's hot in here.

I've read that there are such things as battery-powered A/Cs but I don't know much about them.

Yes, some people hearing this story have insisted that there are air conditioners that would work with the current voltage/amps. But I would have to convince my landlady, and how would I do that? (I mean scientifically. I'm NOT asking for help with social engineering).

posted by bingo to home & garden (22 comments total)

I doubt you'll find an efficient battery-operated air conditioner, but you can always try the $30 homemade air conditioner that uses a fan, an aquarium pump, and some ice. It will most likely work with current circuits, and the landlady wouldn't find out about it, except of course when she sees you carrying bags of ice in your room.
posted by SteveInMaine at 12:47 PM on July 3, 2006

Does she have a refrigerator at this house? A full-size fridge will draw more amps than a small window unit AC. If she's really concerned about too much current draw burning the house down, she should get rid of the fridge. Or, you know, have an electrician come over and check the place out. An electrician's visit is a lot cheaper than losing all your stuff in a fire. A neighbor of mine once suffered a serious fire (nobody hurt) caused by 70-year-old wiring and a fridge drawing too much current. Then again, I lived in a 100-yo house with only 4 breakers, and ran thousands of Christmas lights without any ill effects. Go figure.

I'm not sure what the point of a battery-powered AC would be, since you'd need to recharge the battery, presumably off the house's electricity, putting you right back where you started.
posted by adamrice at 12:53 PM on July 3, 2006

If it doesn't have to plug into the wall, then whether or not the landlady finds out about it makes no difference. But the ice thing is too inconvenient to make it worthwhile. Interesting link, though.
posted by bingo at 12:55 PM on July 3, 2006

They definitely exist; try googling about camping and fishing supplies... people use them on their boats and in small cabins when they're out in the wilderness.

I use this one in my car and, as you can see from the specs, it's the same design as the DIY one that SteveinMaine linked to, and it uses very little power. However, it does not quite feel like air conditioning. I'd say it's the difference between life and death in my car in the summertime, but I still get very very very hot.
posted by xo at 12:56 PM on July 3, 2006

A battery powered unit would either cost you several thousand dollars worth of disposable batteries or draw even more power off the circuit when it was recharging. The energy has to come from somewhere. They may exist but I don't think they will be of much use to you.

You want to convince your landlady to allow you to have an air conditioner, just start withholding rent because you are miserable. (Now the lawyers can tell me why I am wrong and how bad this is)
posted by 517 at 1:15 PM on July 3, 2006

I moved in here knowing the situation with the lack of a/c and the old circuitry, and a verbal agreement that we would talk to some electricians and try to find one that makes her happy. We are still looking. Again, I'm absolutely not looking for advice on how to deal with the landlady.

The issue is not how much power is drawn from the circuit, it's that the circuit is not built to sustain the voltage used by an air conditioner; i.e. it's a safety issue. If the recharging of the battery doesn't draw the same voltage as an air conditioner, then it's fine.
posted by bingo at 1:24 PM on July 3, 2006

It violates the "inexpensive" route, but has other uses - have you considered a cheap/small portable generator? Put the generator outside with a cord to a standard A/C, meaning you can buy and use a mains A/C right away while still dealing with electricians, and the generator pays for itself during the next storm blackout. In an urban area, how quiet a generator you could get would probably be a factor through if you have neighbours close by.
posted by -harlequin- at 1:25 PM on July 3, 2006

You could also run a standard mains A/C off a car battery via an inverter. If the battery takes 10 hours to charge, and runs the A/C for 1 hour, then you know the charger is drawing a lot less power through the old wiring.
posted by -harlequin- at 1:28 PM on July 3, 2006

The issue is not how much power is drawn from the circuit, it's that the circuit is not built to sustain the voltage used by an air conditioner; i.e. it's a safety issue. If the recharging of the battery doesn't draw the same voltage as an air conditioner, then it's fine.

This is what fuses/circuit breakers are for. Perhaps what you need an electrician to do is not check that the wiring for that one spot but that all the circuits are properly secured and up to snuff.

As far as energy consumption there's no way any battery powered thing will draw less power - simple entropy demands that if you pull X units of power out of some storage device that it will have taken X+Y units of power to shove those X units in.

The only thing that might obviate this for your purposes is if you spend more time charging the device than discharging it. However likely that might be, you can't guarantee this to be true.

You may not want advice on how to deal with your landlord but what you have is 100% a landlord issue, and one without any real technological solution.
posted by phearlez at 1:42 PM on July 3, 2006

You could get a heat pump-based AC unit from a company like Fujitsu. These are much smaller and quieter than the ridiculously huge GE-style humidity extracting windy ACs that seem to be overly popular in the US. Your landlady might not even realise it was there or what it was - you could tell her it was an ioniser or similar.
posted by meehawl at 1:48 PM on July 3, 2006

Ohm's Law is your friend in truthiness, but you're probably looking for something a lot more basic, and demonstrable.

For a very small window unit like this, you get an Energy Guide rating plate like this, and an annual cost of operation estimated at $35.53. It uses standard 110/120 volt AC power, and will pull about the same power as 4 standard 100 watt incandescent white light bulbs.

If your circuit can power 4 standard 100 watt incandescent light bulbs, it will handle this air conditioner. So, plug in 4 standard 100 watt lights to the circuit in question, and see what happens. If you live in a place where any circuit can't keep 6 standard 100 watt light bulbs running continuously, move out before you die in a fire.

The only issue in question for use in an older house is whether you have a 3 prong grounded outlet available on the circuit. If not, you can have an electrician install one on an outside wall, usually for less than $100.
posted by paulsc at 1:54 PM on July 3, 2006

I'm guessing this isn't the answer your were expecting (hoping?) for, but you could try Angie's List to help find a good electrician -- it's basically a service where users can rate service workers (such as electricians, plumbers, and so on). It's not a free service but, speaking as a new homeowner, it's already paid for itself :).
posted by Alex Handcoding at 2:03 PM on July 3, 2006

Depending on what comes into the house at the main circuit box, you could perhaps add another 15 amp circuit in the form of a plug right at the box, with its own fuse/breaker. This is relatively cheap and easy. Then you could run a heavy duty extension cord to the air conditioner.
posted by StickyCarpet at 2:29 PM on July 3, 2006

inexpensive, battery powered, and any use to you in this situation? no.

I suppose it depends on your definition of inexpensive, but all the cheap options would be barely more effective than nakedness, talcum powder, and a good exaust fan.

(I spent the first 20 yrs of my life in a circa 1896 un-airconditioned home in Georgia summers)
posted by Megafly at 2:44 PM on July 3, 2006

One issues is that although most modern window A/C units may draw a limited amount of current in steady-state, many have draw a big spike of current when the compressor starts. I had to switch to delay fuses with a previous window unit because it would blow out a standard 20A fuse. The delay fuses (any any hardware store in an area with old houses should have them) wait a few seconds before they kick out to let compressor motors start up.

But to a previous poster, a fan plus copper tubing, a bucket of water and an aquarium pump actually works pretty well. Especially if you throw in a few big chunks of ice. Pump the water out the window into a garden to minimize stinky water. It may be wasteful of water, but that sounds like less of an issue than electricity in your case.
posted by GuyZero at 3:37 PM on July 3, 2006

this company makes a natural gas powered air conditioner for home use. Can't seem to figure out where to buy it from. They also make a solar AC unit.

Batteries just won't provide enough power to run an AC very long. The simplest option would be to buy a generator and run it on gasoline. But most likely your wires are fine for an AC. Get it checked by an electrician and then you should be able to buy an AC.
posted by Paris Hilton at 3:42 PM on July 3, 2006

More or less completely off topic at this point, but..

One time delay fuse I'm familiar with (bussmann MDL series, for an electronic device, not household fuse box) will only blow after at least one hour at 135% of rated current. So, I would be tempted to select a lower current rating, if a sensible choice was available.
posted by Chuckles at 4:23 PM on July 3, 2006

Just to follow-up on PH's post, here's an explanation of how gas-refridgeration works -- it's the same basic principle for air conditioners. My girlfriend's friend used to sell tools and appliances to the Amish, and these were apparently quite popular.
posted by Civil_Disobedient at 4:29 PM on July 3, 2006

paulsc: I sent her the link to the 115v A/C you recommended...have you ever actually used one of those? It almost sounds too good to be true. I wonder if it will actually cool the room.

There is indeed a three-prong outlet in the room in question.
posted by bingo at 5:48 PM on July 3, 2006

...also, it does say A TIME-DELAY FUSE OR CIRCUIT BREAKER AND SEPARATE CIRCUIT IS RECOMMENDED. (caps theirs)
posted by bingo at 5:57 PM on July 3, 2006

bingo, 5500 British Thermal Units (BTU) of cooling per hour isn't a whole lot, by air conditioning standards, but in a 150 square foot room, with normal ceiling heights and some insulation, it should be adequate for NYC. 143 BTU is required to melt a pound of ice. A gallon of water weighs about 8 pounds, so a machine of this size would provide the cooling of melting about 6 one gallon jugs of frozen water per hour.

Moreover, one of the things about an air conditioner, is that it not only cools air, but dehumidifies it. Water taken out of the air drains to the outside by gravity, if you set the air conditioner in the window as recommended, and your room air is then able to evaporate more water from you and your surroundings, because the air has been effectively dried. Hence, you feel cooler than you would, just from pure BTU heat transfer.

Obviously, heat gain from the outside can offset this. If you have big windows, poor insulation, south exposure, or a heat generating appliance like a refrigerator or computer in the room, the air conditioner will have to transfer the heat load those things are contributing back to outside air, before it can cool your room air below outside temperature. So, if you have a lot of these conditions, you'd need a bigger air conditioner (more BTUs), which would probably draw more power, and that, you say, is a no-no.

Still, something is far better in July and August than nothing. Good luck.
posted by paulsc at 6:57 PM on July 3, 2006

Well, thanks for all the help. It looks like I won't be getting any a/c this summer. And the landlady actually expected for me to pay for the electrical work to add a new circuit, so that's not going to happen either. I'm moving as soon as possible.
posted by bingo at 6:28 PM on July 12, 2006