Air conditioning alternatives?
February 11, 2014 2:25 AM   Subscribe

To prepare for summer I'd like to install air conditioning, but don't want the huge electricity bill. What are some alternatives?

Last year we kept the windows closed and used a fan to circulate the air. This worked, but not well enough.

I looked at evaporative cooling on wikipedia, but I worry about electronics and mould. Window films might be an option as long as they aren't too visible. What are some other options? Any alternatives welcome!
posted by gorcha to Home & Garden (29 answers total) 7 users marked this as a favorite
If you install a heat pump, it will do A.C. well and while the bill will be the same for that, it will slash your heating bill in winter - it's far more efficient than electric heaters.
posted by anonymisc at 2:32 AM on February 11, 2014 [1 favorite]

Some good advice here.

I'm generally bemused by the idea of closing windows in summer. It is rarely necessary except in the hottest, most humid climes. In general, people have stopped being smart about shielding and evacuating heat from buildings in summer, preferring the brute force option of air conditioning.

Instal solar to use and absorb the heat and offset your costs. Use your windows properly to create an air flow and ventilate your house. Use fans to move warm air out. Remove humidity in closed rooms with a dehumidifier. Use shutters and physical barriers to shield aspects that take the brunt of the sun. Cook outside. Live downstairs as much as possible. In short, treat cooling your home less like a one-off fixable problem and more like a lifestyle.

I'm British, so warm sunny days are lovely and rarely oppressive. But even when living in the tropics, I've used air conditioning as a last resort. Fans and moving air are much more pleasant in my experience.
posted by MuffinMan at 3:05 AM on February 11, 2014

Currently suffering through a 38-42 degree (C) heatwave without air conditioning (where, MuffinMan, you really do want to keep windows shut during the day, as you can generally keep the house at least five degrees cooler than the outside that way). We have developed the habit of keeping the curtains closed all day and only opening them (and the windows) up once the outside temperatures drop below the inside ones in the late evening. Very little else makes much difference. Fans circulating air around the house as a whole just add extra heat, but having ONE fan on, blowing directly into your face, is very pleasant.

Then multiple short (30 second) cold showers a day, especially before bed, spending quality time lying naked on the tile floor, and sucking on ice cubes are also pastimes that feature prominently in my life lately.
posted by lollusc at 3:34 AM on February 11, 2014 [8 favorites]

Oh, and in case it wasn't clear from my comment, we leave the curtains and windows open all night too, getting the house as cool as possible before closing it up again in the morning.

(Don't leave any doors open, though - we got burgled that way a couple of summers ago. The police said burglars wait for heat waves and then go around all the houses that have left doors open for night time cooling.)
posted by lollusc at 3:35 AM on February 11, 2014

One final suggestion: if there are rooms of your house that get hotter than others, keep them sealed off on hot days, or during the hottest part of the day. Our spare bedroom is basically off-limits all summer, with curtains drawn and door closed, because the sun hits it solidly all afternoon. Same with the (connected) garage, which is worse because uninsulated. The temperature difference between those rooms and the rest of the house can be 10 degrees or more, so it makes sense to keep them blocked off.
posted by lollusc at 3:39 AM on February 11, 2014

@anonymisc: our winter heating bills aren't a problem, they're pretty low, but I'm googling heat pumps for aircon right now. I'd like something unobtrusive and small to keep the neighbours happy really.

@MuffinMan: We found that keeping windows closed, like lollusc says, really does help. Five degrees for us. If we were to open windows the only way we could get a draft going would be to open on both sides of the building, but this creates a window tunnel of such force that the doors start slamming and everything is blown everywhere.

@lollusc: thanks for all the tips! Our south side is where we spend most of the day, and it's the hottest side. I'm going to try "going dark" this summer with blinds, but would like to avoid that if possible. Maybe with a film that I can apply to the glass. Something that isn't too visible would be best, particularly in winter.
posted by gorcha at 3:42 AM on February 11, 2014

In general, people have stopped being smart about shielding and evacuating heat from buildings in summer, preferring the brute force option of air conditioning.

This is something that happened decades ago, well before most of us were born, when energy was a lot cheaper than it is now. It seemed like a sensible idea at the time. Now we're stuck with a lot of houses that are pretty unpleasant without AC.

OP, what's viable for you will depend on climate. Where do you live?

In high school (also decades ago) I painted houses during the summer breaks. This was in northeast Ohio, which can get very humid and has annual high temps that typically flirt with 100F. One lovely house had a whole-house fan that worked so well it seemed like magic. This was a large, powerful fan, maybe 3' in diameter, mounted over a grille in the top-floor ceiling. When switched on, it sucked air out of the house and exhausted it into the attic, which in turn was vented to the outside (probably through larger than average gable vents, but I don't remember). The negative pressure inside the house would pull in a nice breeze through any open window. At night they'd open many windows and pull lots of cool outside air through the house, quickly exhausting the heat of the day. Even when it was warm outside, they could open some basement windows on the shady side of the house and get a noticeable benefit. I remember thinking my boss was kidding when he told me the house didn't have AC, because it was so comfortable inside despite the weather being miserably hot and humid out on the ladders.
posted by jon1270 at 3:48 AM on February 11, 2014 [1 favorite]

Keep a supply of chilled water in the fridge and drink it.

And -- this is a guess -- big leafy houseplants? They evaporate a lot and getting water to evaporate soaks up energy.
posted by batter_my_heart at 3:49 AM on February 11, 2014

I also came to say you should consider a whole-house fan. They really are magical, and quite energy efficient. How well insulated is your house? Upgrading the insulation might also help.
posted by medusa at 4:44 AM on February 11, 2014

I hate air conditioning. We generally made it through hot weather by beekeeping blinds down during the day and and at night using top floor window fans facing outward. An attic fan might be happening this year. The only time we use the air con now is during heat waves that don't cool down at night.
posted by bonobothegreat at 5:00 AM on February 11, 2014

Just as a datapoint, I live in the U.S. south where our summers are extremely unpleasantly hot and humid, and my AC bills are always less than our heating bills in the winter. It might not be as expensive as you're thinking.
posted by something something at 5:10 AM on February 11, 2014 [2 favorites]

I never had air conditioning, not even window units, until I moved to Florida 9 years ago. I moved there in May, thought I would try to avoid using the AC as much as possible. I didn't last long. If I had had the money I would have installed something like this solar attic fan. A cursory look indicates they've come way down in price since then.

If by some chance you have a basement you could try what my uncle did in suburban Washington DC many years ago: leave the basement door open, close all curtains/blinds on sunny side of house/ put window fans in two windows upstairs- one fan sucking air in from the shady side, and one blowing it out. The cooler air got sucked up from the basement and flowed through the house and out the upstairs. It worked quite well, even in the horrendous humid summers. Speaking of humidity, if high humidity is a big problem where you are you could try using a dehumidifier.
posted by mareli at 5:44 AM on February 11, 2014 [1 favorite]

If you live in an area with dry summers you could us an evaporative cooler (aka swamp cooler). They are common in Phoenix, although in monsoon season they lose effectiveness due to increase humidity. No need to worry about mold or damaging electronics. The moister in air of a home being cooled by an evap cool is still much lower then the moister in a humid climate (ie Florida). In fact once the air becomes humid enough the evap cooler does nothing, which is why they are only effective in bone dry desert climates.

Whole house fan is a good idea as well.

Both solution require need airflow from outside, so some windows will need to open to work.

As for more passive solutions. You can embrace the windy cross venting of open windows (invest in paper weights and door stops). That is the natural, non enhanced, version of the whole house fan solution. Also lower the amount of sun exposure on your home during the summer. This can be accomplished with extend eaves or screen walls or shade trees/landscaping that shade your exterior walls during the summer. If you have a masonry home this particularly important.
posted by Ommcc at 6:03 AM on February 11, 2014 [1 favorite]

Pros of a swamp cooler - they don't use a lot of electricity compared to AC, and they're simple machines that most people can work on. Cons - if you live in a climate with any humidity at all, it's not going to do you any good. Ours works great until monsoon season, and once the dew point clears 50 degrees it's pretty well worthless.

Look into a whole house fan. They're not horribly expensive. Heat rises, and these fans take the heat that's accumulated in the attic and blow it outside.
posted by azpenguin at 6:14 AM on February 11, 2014

Tips I've used for getting through very hot and humid nights without an air conditioner in New York:

1. cool showers (not freezing-cold, that just shocks your system), but use Dr. Bronner's peppermint soap. There is a crapton of peppermint oil in it, and the menthol in the peppermint oil has a cooling effect on your skin that lasts for a while.

2. When you go to bed, get an extra sheet, then get it wet; either just damp if you're uneasy about dripping, or pretty soaked if it's really hot. Then sleep UNDER that wet sheet. It'll have more or less dried by the time you wake up, and in the meantime the wetness and the evaporation will keep you cool at night.

3. You can use a similar trick during the day (for more casual attire days) by wetting your shirt before putting it on. That's actually how I came up with the sheet trick, was by adapting this one; on a July 4 trip to Washington DC, I got desperately hot about mid-day; I was wearing a button-down shortsleeved shirt over a tank top and shorts, and in desperation I took the button-down shirt off and dunked it in the reflecting pool at the Lincoln Mall and put it back on. I got some funny looks, but I was considerably more comfortable for the rest of the day so I had the last laugh.
posted by EmpressCallipygos at 6:15 AM on February 11, 2014 [1 favorite]

in desperation I took the button-down shirt off and dunked it in the reflecting pool at the Lincoln Mall

....i'm not sure you realize how full of duck feces this used to be. I hope this was after, not before these changes were made.

Agree with whole house fan - but any reason you're not considering a window unit here or there? they make a lot of sense and let you spot cool here and there. I use them in my 1904 bungalow.
posted by waylaid at 6:28 AM on February 11, 2014

It's hard to make good recommendations without knowing more about your climate and schedule, but what works for me is keeping all the blinds down (and windows closed) during the day when I'm at work, then opening all the windows and really getting some cross-breezes going as it starts to cool down in the evening. I also use a window unit in my bedroom for the warmest nights. This is in New England, and generally at my place no one's home on weekdays (for work) or really much on weekends (I like to spend as much of summertime outside as possible).

I also just avoid doing anything physical in the house on hot days. I leave the cleaning for when it's cooler.
posted by mskyle at 6:56 AM on February 11, 2014

This is very difficult to answer with more than guesses unless we know where you are and what the average temperatures and humidity are like.
posted by Lyn Never at 6:59 AM on February 11, 2014

Central Europe. Apartment. Temperatures reached 40 degC in summer last year.

So unfortunately a whole house fan (never heard of them before today) won't work, and insulation is already good.
posted by gorcha at 7:04 AM on February 11, 2014

Does it cool off at night, or do you just get a long miserable run of hot without much relief?
posted by Lyn Never at 7:07 AM on February 11, 2014

In Europe, it should be fairly easy to get shutters, in a light colour. They are much more effective at blocking the sun out than blinds, since they are on the exterior side of the window. If your insulation really is good, AC shouldn't be that expensive, since your heat gains will be relatively small. Look into "minisplit" units (made by Futjitsu, Mitsubishi, Daikin, etc.); if only certain rooms are hot, you can install indoor units in these particular rooms only.

A heat-recovery or energy-recovery ventilator (HRV, ERV) may help you save a bit of energy and keep your house cool. If nights are much cooler than days, you'll want an (H/E)RV that has a bypass option (so the hot air exiting the house doesn't warm the cool air entering it).
posted by Monday, stony Monday at 7:51 AM on February 11, 2014

One way to set up temporary evaporative cooling is to hang a wet sheet and put a fan behind it, blowing air into it.

This will work in a dry heat, it's rather useless in humidity.

You can install energy efficient window units, for the really hot days.

Ceiling fans are good, and by changing the direction of the blades, you can drive cool air down, or draw warm air up (depending on the season.)
posted by Ruthless Bunny at 7:59 AM on February 11, 2014 [2 favorites]

2. When you go to bed, get an extra sheet, then get it wet; either just damp if you're uneasy about dripping, or pretty soaked if it's really hot. Then sleep UNDER that wet sheet. It'll have more or less dried by the time you wake up, and in the meantime the wetness and the evaporation will keep you cool at night.

This. I also sometimes put a towel down on the bed, run a vest under the tap, wring in it out a bit and sleep in that. You can put a wet washcloth over your face as well.
posted by hoyland at 8:28 AM on February 11, 2014

If it gets hot here in the UK this year, I'm going to make a home-brew air conditioner.

It's better to prevent the heat from getting in in the first instance, though. I have a sheet of 3mm acrylic attached to a window surround (using magnets, so no need to drill holes). I get about a 10 degree difference between the "inside" and "outside" of this set up. More if I pull the blackout blind down.
posted by Solomon at 11:11 AM on February 11, 2014

Does it cool off at night, or do you just get a long miserable run of hot without much relief?

It gets much cooler, but it's still very warm.

I'll look into minisplit AC units, external blinds and recovery ventilators - thanks!

Also for the other answers, any ideas welcome :)
posted by gorcha at 3:30 PM on February 11, 2014

As an Australian, I love my AC, so I'm going to vote for that. But be smart. Cool one room and use that as a refuge, rather than cooling the whole house. This should be either your largest bedroom, or a shady down-stairs room that you can close off from the rest of the house and you can sleep in. Don't keep it ridiculously cool, but cool enough that you can comfortably sleep at night (low humidity helps here) and function during the day. Use a draft excluder and make sure the windows seal. Keep the curtains (thick and thermal-lined, hopefully) closed if possible to keep the heat out and don't have people running in and out all the time.
posted by ninazer0 at 3:39 PM on February 11, 2014

For the record, whole-house fans are terrible in places where humidity routinely tops ~70–80% (like here in the mid-Atlantic US).

My wife and I used to live in a house with a whole-house fan, and the entire house was slowly mouldering. The humidity had, over decades, soaked the drywall throughout the house, which was buckling, and the paint was bubbling up and peeling off. Our dry goods didn't stay dry unless sealed up tight. (Salt shakers turned to salt cylinders, malted milk powder adopted the shape of the container, never to be chipped out.) Everything cold generated condensation—pipes under the sinks and the toilet, the toilet tank itself, even a glass of cold water would have rivulets running down the side in no time. We finally stopped using the fan, and instead made white (reflective) insulating curtains to cover the windows, installed overhead fans to keep air circulating, and got in the habit of wearing very little clothing at home.
posted by waldo at 5:35 PM on February 11, 2014

Indeed, as the article I linked to states:
Ventilation can only reduce the indoor relative humidity if the outdoor air is dryer than the indoor air. Since cold air can’t hold as much moisture as warm air, ventilating a house helps lower the indoor relative humidity only when it’s cold outside (or on dry days during the spring and fall). In most parts of the U.S., ventilation during hot weather actually introduces more moisture into the house — that is, it tends to raise rather than lower the indoor relative humidity.
So a whole-house fan in the Southeastern United States is pretty useless to reduce humidity. You need AC and/or a separate dehumidifier.
posted by Monday, stony Monday at 6:28 PM on February 11, 2014

When I was young and short of money in north Texas, I found that unplugging the heater on the waterbed and sleeping on a thin or no sheet helped a great deal - . Even if it's only a couple degrees cooler than body temperature, it's a great heat sink. Desperate times, desperate measures. I still sleep on one, and in a few minutes, will crawl into my nice warm bed in the house I don't have to heat as much as otherwise.

Our big box hardware stores sell little 2 fan units that are designed to fit semi-tightly into a window frame, and are reversible. One of those in one window of a room, open the other window *just a bit* and you'll have much the same effect of the whole house fan.
No, fans don't reduce humidity. If you have stoopid high humidity in your area, it might not be the solution.

I also lived in the Florida Keys for a while, where stoopid high humidity originates. They ship it out to the rest of the country as they have a great natural supply. We had a landlord supplied window A/C unit that helped, some. I bought a de-humidifier, just a box on the floor that plugged in and had to be emptied once a day, it helped immensely.

If you've ever lived in the high desert, 100F /38c ain't that bad. Walking around comfortably in the snow with a pair of jeans and a sweatshirt on is also entertaining. No humidity makes a great deal of difference.
posted by rudd135 at 7:08 PM on February 11, 2014

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