"Air conditioning" in a humid climate, without air conditioning

We moved in to our new home last year in the middle of what many people around here say was one of the hottest summers anyone has seen in a long time. New Hampshire has traditionally had such a mild summer climate that few houses have air conditioning. Even if they get a little warm during the day, you can usually open the windows at night to cool the house back down to a tolerable level by morning. Last summer, though, we had almost two straight months of daytime temps in the upper 90s with 70+ percent relative humidity, and it would only drop down into the 80s overnight. Our house’s long axis faces southwest, and 85% of our windows face either southwest or southeast. When temps were in the upper 90s the temperature of our living room would reach the mid-90s by dinner time, and our bedroom upstairs would be the same temperature as the ambient air. The best we could hope for at night was for it to cool back down into the low 80s before the next morning.

We couldn’t do much about it at the time. Between having a child in January and buying a house in June we were financially tapped out. But with a young child (the risk of death by SIDS goes up dramatically if the child sleeps in a room kept warmer than about 70 degrees), and a wife who despises (and complains loudly and frequently about) being overly warm I knew I had to try and do something about the situation as quickly as I could. Purchasing air conditioning units – even window shakers – was out. Whole house because of the cost, and window units because all of our windows are casement style (i.e. they open sideways like a door) and most window units are designed to be placed in double hung windows.

But honestly, we’re too reliant on air conditioning to make our life bearable, anyway, so I wanted to try and alleviate the problem as much as possible via other means first before resorting to that. What follows is a record of what we’ve done or plan to do, and if applicable, how well it’s worked.

The first thing we tried was putting reflective film in all of the windows that receive direct sunlight during the day. That made a small but noticeable difference – about 3 or 4 degrees. It wasn’t terribly expensive, either. We paid about $30 for enough rolls of the stuff to do virtually every window in the house. (Only 4 get no direct sunlight at any point during the day.)

Next, I purchased a couple sheets of 1/2" foam board, which is just the right thickness to sandwich between the windows and the window screens in our house. I cut a piece to fit each non-north facing window upstairs, glued aluminum foil to one face, and pretty much permanently installed them in their respective windows for the remainder of the summer. With curtains drawn over them you can’t even tell they’re there. Fortunately, we have one north facing window upstairs, so we still have enough daylight to see by without having to turn a light on during the day. This lowered the temperature of our bedroom to only about one or two degrees warmer than the temperature in the living room one floor below. I offered to give the main living area the same treatment, but my wife decided she would rather have the natural light in the living room even if it meant heating up the house more. She doesn’t spend the entire day outdoors like I do, so I can understand that.

That was all we had resources for the first summer. Over the winter I installed a couple ceiling fans in the main living area to help with air movement. Obviously, that doesn’t cool the house any, but it certainly feels better – especially if you happen to be sitting under one. We also purchased a couple of additional dehumidifiers to go with the one already in the basement. Although the one in the basement was nominally rated to cover the square footage of our entire house, in reality it could only keep up with the floor it was on. The upper two floors maintained relative humidity above 70% for most of the summer. Adding two smaller dehumidifiers on the upper floors has allowed us to keep the RH in all parts of the house in the 40-50% range. The dehumidifiers do warm the house up slightly while running, but it feels more pleasant because the air is drier.

This spring I built a shade awning over the elevated deck which most of the windows in the house face. Now we don’t have direct sunlight on the living room windows until almost sundown. We haven’t had weather like last summer yet to really test it, but initial results look promising. A couple weeks ago we had a good solid week of 80-degree days, though it cooled off nicely in the evening. We’d leave the windows open at night to reset things and the house would only be in the upper 60s at five when we’d start cooking dinner. Last year we’d have been within a degree or two of the outside air temperature. We aren’t expecting miracles from this. You can only get as cool as your night time low, but at least we won’t regain heat so fast.

Going forward, we want to build some kind of outdoor kitchen. Cooking a meal on our stovetop raises the temperature in the living area by three to five degrees, and baking anything adds anywhere from five to ten. I figure the easiest way to remove heat is to not add it in the first place. We can grill right now, but I don’t want to be burning propane all the time. A cob baking oven and a J-tube wood burner would be nice. I just need to create a flat spot for them first.

What are we missing? If you live in a humid climate, what have you had success with that we aren’t yet doing?

You never mentioned trees. I  built our house long and narrow, with two windows facing north, and dozens of windows facing south. It adds a great deal of heat and light in the winter. Around the base of the house I planted ewe bushes. They break the winter wind before it hits the house. So we also stay warmer that way. For summers, I planted trees, lots of trees. Deciduous trees. They give great shade in the summer, so our house never really heats up. And for winter the leaves fall so we, again, get more light and solar warming. The fastest growing deciduous trees I know of are cottonwoods. They are kinda messy this time of year with dropping copious amounts of seed "cotton". But they grow fast. Then you can intermix maples or oaks or black locust (another almost as fast grower). When the "better" trees get to size for shade, you could remove the cottonwoods if you don't care for them. They are a soft wood, but they burn pretty good in the wood stove.

A whole-house fan, drawing the air out through an upstairs window, with the remaining windows all at half-open, or less, will create a draft strong enough to cool a house, drastically. On very hot days (95°F and higher, with 70-80%humidity), in Chicago, our house was cooled 10 - 15degrees, in very short order. At night, the temps dropped enough, in the house, to require a light blanket, at night, rather than just a sheet. Strategic placement, and a powerful fan are key.

You could also move where you sleep.  Australian houses often have verandas all the way round. In the heat it is easy to move your bed outside into the breeze.

Jim Fry wrote:You never mentioned trees.

One thing we have plenty of here is trees. Fairly decent sized ones - 40 or 50 feet for the most part, with the overstory white pines 70-90 feet tall. I'm pretty bummed because it looks like the only place near the house I could put a garden is on the southeast side, which would require cutting down most of the trees that have any effect on the house temperature. They really only provide shade until about ten o'clock, though. The sun is up above the tree line after that until dinner time.

Living in various houses and apartments without AC or with no insulaton and inadequate AC near the hot and humid shores of Lake Ontario, I've figured out the following, hopefully something is helpful

- fridge and hot water heaters are huge sources of heat in a house. My grandma used to keep her fridge on a side porch (old summer kitchen) of her AC free farm house. I have always thought having the water heater out of the living area would be super nice. Or maybe insulated around?
- light management is hugely important. I like a double system of light filtering blinds to provide light when I am home, and blackout drapes to cover windows before I leave for the day. I also keep drapes closed unless I am in the room. I think of it as flicking a light switch when I open them.  I open windows at night and close during the day.
- cross breezes in the early morning from open opposite windows is really useful. Coolest time is generally just before sunrise.
- I use an instant pot a lot in the summer, or cooK in the microwave, and sometimes use an electric frying pan. It's a lot less hot than having the stove or oven on. I also cold brew my coffee. My grandma used to have a stove out in the garage for summer baking.
- unplug electronics not being used, use led bulbs. I love incandescent light but can definitely feel the difference in heat.  Turn off lights when possible!
- cool wash cloths applied to the face are wonderful. Also to the palms and soles of feet. I have even taken one with me to bed and out it on my pillow. And go to bed with wet hair.
-get used to the temps. The worst is when you go from an over ACed workplace to a hot house. When you just live in heat all the time, your body does adjust.
- exterior colour really matters! Hottest I have ever been was an upstairs apartment with insufficient ac, tucked under the eaves of a black roof. Other apartments without AC were much cooler!  Maybe too expensive to change, but if you are planning on painting or a new roof, a light colour would make sense.
-thermal mass is great if you can get it.

I am staying completely comfortable 8 degrees from the equator at sea level. Evaporative cooling is very important. Although the humidity is high , you still get evaporative cooling when water is applied to any hot surface. We have a tile floor that is about 300 square feet when it starts getting hot i apply about 5 gallons of water. Slowly flows toward one side of the room. A broom is used occasionally to make sure that the whole floor is wet. A fan is directed at the floor on an angle so that it dries a 10-foot portion. Bare feet can feel the heat being sucked out of them.

About an hour before dark the most powerful fan is placed outside of the door about six feet from it. This distance takes full advantage of the Bernoulli effect . The amount of air moving into the house is much more than the amount expelled from the fan. Ventilation through the door happens until bedtime. Then a fan is placed outside of a window and left on all night. If i wake up to pee, the floor is wet again ( water not pee). We usually wake up to nice cool floors which cools the whole space.

If I'm going outside for very long , I wet my pants and shirt . Sometimes completely wet and other times just damp. I usually soak them and then put them in the spinner of the washing machine for about 5 seconds. This keeps me cool for between one and two hours depending on conditions.

Someone mentioned southern Ontario.  I was surprised to find that it's easier to get cool here in the tropics than it is on a sweltering night in Saint Catharines Ontario, where I thought I might die of heat exhaustion or simply rot.

My much-better-half and I live in a third-floor apartment in Toronto with no AC. We open the three windows we have, use fans strategically, and remove lots of clothing whenever possible.

The absolute worst is that my workplace is so ACed I often feel like hanging meat. I should make a pit-stop by the butchers and pick up a carcass to hang from the ceiling.

I love the evaporative cooling in the tropics, Dale. Reminds me of the brewing shop in that BBC Tudor Monastic Farms documentary, where they cooled the room by dampening the clay tile floor and encouraging a cross-breeze.

Now this won't work in an environment designed for maximum through-flow of air, but in a humid temperate climate, where the air intake for the house is coming in from the side of the house away from the sun, I would imagine that if something like an airwell was placed in the path of the incoming humid air, that airwell would cause at least some of the humidity in that air to condense out, leaving the air entering the house drier and more capable of evaporative cooling, as it would have a greater capacity to carry away moisture.

We have a Flemish Giant rabbit that free-ranges in our kitchen, and when we're home to hang out, with us in the rest of the house too. One of the chief concerns of rabbit owners is overheating. But while she gets her own little fan and her water bowl is thick pottery, what I really want is a large crock of water to stand in the corner of the kitchen with some cheesecloth draped into it and over the sides. That would cool the whole kitchen, most likely, but also provide dechlorinated water for plant watering.

And there's always the old swamp cooler idea. It can be done open or closed. The open version is simply a block of ice sitting in a drip tray in the flow path of a fan moving air barely fast enough to be detected. You sit in front of the fan, and the air passing over the ice is cooled. Theoretically, if the drip pan, for the sake of argument a cookie sheet, was sitting atop a metal heat exchanger, more air would be cooled faster.

The closed model also involves a fan and ice, but we swap out the drip tray for an old cooler and some cheap ducting. Two holes are cut in the lid of the cooler. One is to the size of the fan you will be using, and the other is about the same size, perhaps a little smaller. The ice block is placed inside the cooler, the fan ducted to the bottom hole, and the air forced past and around the ice block and out the top hole, cooled by its passage.

Now this isn't something I have even seen anywhere before, and I am sure there are reasons not to do it in areas where something would come and take up residence in it, but I had an idea, a thought experiment of sorts. What would it work like if the outer, structural walls of a hut or house were essentially reinforced gabion walls, with large stacked rocks making up the structure? Would the gabion walls act themselves as airwells? Would that make for a less-humid interior environment? And would it also be possible to collect that condensation and direct it to garden beds?

Just a few thoughts. Good to hear from you Dale. Are you amending your signature to include your current location?

-CK

In hot humid climates where there's no refrigeration type A/C or using it is against personal choice, evaporative A/C is probably one step up from a fan.

It only works with good ventilation - doors and windows open. The trade-off in the tropics are mosquitoes and the need to use mosquito netting over beds = makes it hotter! (Mozzies carry nasty diseases.)

Another method is using the 'Coolgardie Safe' principle - hang a water container up over a door or window, drap a loose weave material (like curtain material or hessian) in it so it wicks the water, and let it hang so any warm breeze hitting it will create a cool breeze on the other side. Also needs a basin or trough on the floor to catch the flow.

We had canvass blinds on verandahs and hosing them down after sunset created a similar cooling effect.

Same principle as a canvas water bag traditionally hung on the front of 4WD's in Australia and Africa during the 'Empire' period.

Other techniques we use are lots of timber lattice to block sun but let breezes through, designing houses so all the bedrooms are on the shaded side of the house, and traditionally placing the kitchen in a separate building beside the main house - when wood fired stoves were commonly used.

In another thread Dale mentioned growing a useful vine like passionfruit on a trellis. Combine the lattice and vine on trellis and there's significant benefits.

Anyway, after a few seasons, if you survive the heat and mosquito-borne diseases, you'll probably acclimatise!

I live in southern New Hampshire, so similar climate and struggles as you.  Although we have central air, we try to use it sparingly.

I'm surprised to hear so many suggestions related to evaporative cooling.  In my experience, it's the humidity that makes summer uncomfortable; adding more humidity just makes the problem worse.  Be very cautious about growing mold in your living space.  Leave the dehumidifier running in the basement or it will invite mold growth.  Last summer was so humid that the furniture on our screened porch were covered with mold by August.

We had a whole house fan, but decided to remove it as part of an attic insulation project.  It wasn't practical or useful when you needed it.  At 9 PM in the summer when you're trying to go to sleep, it's still blazing hot outside, and you're pulling in hot humid air which doesn't help.  The time you need it is 4-5 AM when it's coolest outside, but I'm not going to set an alarm to wake up, open all the windows and doors on the second floor before turning the whole house fan on and going back to sleep.

Our dehumidified basement is the most comfortable place to sleep in the summer.  When my wife and kids are travelling, I sleep down there.

You can get a minisplit A/C system to cool down one room, that works with casement windows, and is a lot cheaper to install and run than central A/C

Catie George wrote: I open windows at night and close during the day.
- cross breezes in the early morning from open opposite windows is really useful. Coolest time is generally just before sunrise.

Davis Tyler wrote:We had a whole house fan, but decided to remove it as part of an attic insulation project.  It wasn't practical or useful when you needed it.  At 9 PM in the summer when you're trying to go to sleep, it's still blazing hot outside, and you're pulling in hot humid air which doesn't help.  The time you need it is 4-5 AM when it's coolest outside, but I'm not going to set an alarm to wake up, open all the windows and doors on the second floor before turning the whole house fan on and going back to sleep.

Last summer it didn't seem to matter, but so far this year it has still been cooler in the house than outdoors by the time we go to bed at 10. Fortunately for us, if I'm home I'm up most mornings at 5:30. I open the windows then, and they stay open until my wife closes them about 7:30 or so.

I'm sure it's probably possible, but I wonder how expensive it would be to make an adequate sized vent in the lower floor that would open on a timer in conjunction with a whole house fan that also worked on a timer? And what the difference in energy requirement would be between such a system and traditional air conditioning.

I'm sure it's probably possible, but I wonder how expensive it would be to make an adequate sized vent in the lower floor that would open on a timer in conjunction with a whole house fan that also worked on a timer? And what the difference in energy requirement would be between such a system and traditional air conditioning.

I have no idea, though didn't like the one air exchanger I had. House was stale with it off, hot with it on in summer, cold in winter. My dad has a few mini fans affixed to the wall by doorways to draw heat through the house in winter from a wood stove. It's kinda redneck looking, but works well. And anything not running a compressor should be a huge savings

Do you have a window at the top and bottom of the stairs? We always found trying to draw hot air from the main floor out the window in the upstairs worked well. Depending on your house construction, you may be able to install a register vent to another floor. They are common in old houses that have no heat to the upper stories... like the one I grew up in, and are, not connected to anything but the ceiling below. Not sure what they do for summer though, i always closed mine except on really cold winter days to keep the noise from the main floor out.

Seriously though, if you don't have a moral objection to AC, get a portable  AC on wheels for the bedroom. With a titch of plastic sheeting, you should be able to diy to fit in a casement window. Turn it on for an hour before bed.Turn it off when you go to bed. Life is so much more bearable when you sleep well and the AC should be in a small enough space and short enough duration not to kill you with electric bills....

Mosquitoes don't seem to be a problem here in cebu. Other members of the family have complained but they don't seem to bother me at all. Perhaps they know to not bother a superior vampire.

We aren't getting a little bit of benefit from evaporation. It's huge.  I would guess that we are evaporating about 10 gallons per day from floors and other surfaces. Once it warms up in the morning and it's time to close the door, the fan is directed over a pool of water that sits in the lower corner of the room. There's about a 30 square foot area that becomes the evaporation pond. Air flows along the floor and then the cool air shoots up the wall and around in a circular pattern. This section of floor is much colder than the dry section.

We came home to hot floors a few days ago , so I used about 10 gallons all at once.

Dale Hodgins wrote:We aren't getting a little bit of benefit from evaporation. It's huge.  I would guess that we are evaporating about 10 gallons per day from floors and other surfaces. Once it warms up in the morning and it's time to close the door, the fan is directed over a pool of water that sits in the lower corner of the room. There's about a 30 square foot area that becomes the evaporation pond. Air flows along the floor and then the cool air shoots up the wall and around in a circular pattern. This section of floor is much colder than the dry section.

That sounds pretty nifty if you have a suitable floor like tile or linoleum. We do not (two stories have carpet and one has softwood plank).

Catie George wrote: Seriously though, if you don't have a moral objection to AC, get a portable  AC on wheels for the bedroom. With a titch of plastic sheeting, you should be able to diy to fit in a casement window. Turn it on for an hour before bed.Turn it off when you go to bed. Life is so much more bearable when you sleep well and the AC should be in a small enough space and short enough duration not to kill you with electric bills....

We did try that. Problem for us was that our bedroom is 600 square feet (it's the entire third floor), and the most powerful AC unit we could find was only rated to 500 square feet. We bought it anyway and hoped for the best, but it couldn't keep up.

This joke about immigrating to the tropics was doing the rounds a while ago:

Diary of a Pom in Darwin

August 31
My company just transferred me from Leeds UK to our new home in Darwin, Northern Territory, Australia. Now this is a town that knows how to live! Beautiful, sunny days and warm, balmy evenings. I watched the sunset from a deckchair by our pool yesterday. It was beautiful. I’ve finally found my new home. I love it here.

September 13
Really heating up now. It got to 31C today. No problem though. Living in air-conditioned home, driving air-conditioned car. What a pleasure to see the sun every day like this. I’m turning into a sun-worshipper – no blasted rain like back in Leeds!!

September 30
Had the back yard landscaped with tropical plants today. Lots of palms and rocks. No more mowing lawns for me! Another scorcher today, but I love it here. It’s Paradise!

October 10
The temperature hasn’t been below 35C all week. How do people get used to this kind of heat? At least today it’s windy though. Keeps the flies off a bit. Acclimatizing is taking longer than we expected.

October 15
Fell asleep by the pool yesterday. Got third degree burns over 60% of my body. Missed three days off work. What a dumb thing to do. Got to respect the old sun in a climate like this!

October 20
Didn’t notice Kitty (our cat) sneaking into the car before I left for work this morning. By the time I got back to the car after work, Kitty had died and swollen up to the size of a shopping bag and stuck to the upholstery. The car now smells like Whiskettes and cat shit. I’ve learned my lesson though: no more pets in this heat.

October 25
This wind is a bastard. It feels like a giant fucking blow dryer. And it’s hot as hell! The home air conditioner is on the blink and the repair man charged $200 just to drive over and tell me he needs to order parts from fucking Melbourne ….The wife & the kids are complaining.

October 30
The temperature’s up around 40C and the parts still haven’t arrived for the fucking air conditioner. House is an oven so we’ve all been sleeping outside by the pool for 3 nights now. Bloody $600,000 house and we can’t even go inside. Why the hell did I ever come here?

November 4
Finally got the fucking air-conditioner fixed. It cost $1,500 and gets the temperature down to around 25C degrees, but the humidity makes it feel about 35C. Stupid repairman. Fucking thief.

November 8
If one more smart bastard says: ‘Hot enough for you today?’ I’m going to fucking throttle him. Fucking heat! By the time I get to work, the car radiator is boiling over, my clothes are soaking fucking wet and I smell like baked cat. Fucking place is the end of the Earth.

November 9
Tried to run some errands after work, wore shorts, and sat on the black leather upholstery in my car. I thought my arse was on fire. I lost 2 layers of flesh, all the hair on the backs of my legs and off my arse. Now the car smells like burnt hair, fried arse and baked cat. Fuck. Fuck. Fuck.

November 10
The Weather report might as well be a fucking recording: Hot and sunny, Hot and sunny, Hot and fucking sunny. It never fucking changes! It’s been too hot to do anything for TWO months and the weatherman says it might really warm up next week. Fuck!

November 15
Doesn’t it ever rain in this damn fucking place? Water restrictions will be next, so my $5,000 worth of palms might just dry up and blow into the pool. The only things that thrive in this fucking hell-hole are the fucking flies. You don’t dare open your mouth for fear of swallowing half a dozen of the little bastards! The pool is like a hot bath and we can’t swim at the beach because of crocodiles, sharks and box-jelly fish, FUCK!

November 20
Welcome to HELL! It got to 45C fuckin’ degrees today. Now the air conditioner’s gone in my car. The repair man came to fix it and said, ‘Hot enough for you today?’ I wanted to shove the fucking car up his arse. Anyway, had to spend the $2,500 mortgage payment to bail me out of jail for assaulting the stupid prick. Fucking Darwin! What kind of sick, demented idiot would want to live here!

December 1
WHAT!!! The FIRST day of SUMMER!!! You are fucking kidding me!

It's very simple to construct a blanket fort around the air conditioner , so the you're only air-conditioning about 50 square feet.

Might be interesting to see what the temperature is 3feet down below the surface of the soil there in Cebu, and then figure how much cooled fluid would need to be moved thru a heat exchanger by a solar powered pump to make the idea feasible.

Burl Smith wrote:Might be interesting to see what the temperature is 3feet down below the surface of the soil there in Cebu, and then figure how much cooled fluid would need to be moved thru a heat exchanger by a solar powered pump to make the idea feasible.

Approximately 80 degrees in places that have plant cover. At least 5 degrees hotter in areas  that are completely housing and paving. Nighttime temperatures are in the 70s. The stream of cool air is directed across wet tile and it gets considerably colder than the incoming wind. I've had several people from here check the place out , and the consensus is that this is the coolest house around.

On the hottest days incoming shower water is about 95 degrees . Nobody heats shower water. When we lived in a location where there were lots of trees, the shower water came in considerably colder. Near-surface supply lines.

Right now the temperature is sitting at 82 with 77% humidity. Humidity will drop for a couple hours but it may completely saturate by afternoon and there will be rain. So right now is the best time for cooling. The family have never stored the cold before. Because they lived in a lightweight bamboo house, it wasn't possible. They enjoy the cool floor but without my instruction it would never be wet and cool.

OK I see the prevalent geothermal ingredient is working against me in this argument.

Geothermal Power locations-Philippines

There is a definite sweet spot when using a fan to cool a wet floor. The air travels along the floor smoothly until it reaches the wall. Then because it hits a sharp corner, it billows upward, adjacent to the wall and up to about 1 foot from it. The air is considerably cooler than the hot air entering the fan.

This is where I sit when eating or socializing.

The entire floor is wet . I just walked from the bathroom to the area in front of the fan. I'm guessing that it's 10 degrees colder by the fan. The pool near the bathroom is warm enough for children to swim if it weren't a 1/8 -inch film. When it's really hot i put my bare feet on the cold tiles. Long after the floor dries, it remains cold. A couple days ago Nova's sisters went jogging. When they returned, both laid face-down on the cold floor for a couple minutes and then they turned over and watched television from that position for half an hour.

The whole family were sprawled on the floor one hot afternoon. She said they look like a litter of baby pigs on a hot day. Animals will always choose the right spot on a hot day, if they aren't penned up. My labrador retriever found a seep coming out of the hillside, that dripped onto clay. That became her wallow whenever it got hot.

I always find it strange when people wait until the heat of afternoon to lie on a hot beach.