How can I best keep my room cool in summer?
I’m looking for advice about what sort of portable room cooling devices to look at and what pitfalls to avoid. Some context:
Over the past few years I’ve noticed that I do pretty badly in the heat, especially at night. I live in Zürich, the concept of air conditioning has not yet arrived in this place. The prevailing wisdom for how to survive summer is to just make sure your house doesn’t get too warm in the first place, but my apartment is pretty badly insulated and during the worst weeks it doesn’t cool down that much at night either, so it’s been pretty bad the last few years. I’ve mostly just avoided being in my room whenever possible, but I do have to sleep somehow.
The obvious solution to me is to buy some sort of air conditioning device, a topic I know basically nothing about. My flatmate has one for his room, of the “dangle a tube out of the window” kind, which seems to do an okay job, but it is extremely loud and quite bulky - neither of those are dealbreakers per se, but I’d happily pay a bit more money if that gets me something quieter. In addition, our windows are not sliding windows but ones that open like a door, so any device that requires me to poke something out of the window would probably need a solution for this as well. Any sort of permanent modification to the house such as putting a hole through the wall or the window glass are not allowed.
So my questions are: What types of coolers should I look into, what types are best avoided? Any specific brand or model recommendations would also be appreciated. I looked at one electronics vendor’s website and found a huge range in prices from below 100 to over 1000; I don’t have a specific budget in mind per se, but unless it makes a big difference (e.g. in noise levels) I would rather stay below 500 dollars.
Given that no modifications are allowed, you are likely still looking at a portable air conditioner.
The problem with those is that are really inefficient as most only have 1 hose. For some background see this video. But in short, the way the one hosed ones work creates a vacuum in your room which means that hot air gets sucked in from outside. This is not ideal.
I don't have definitive advice on where to go from here. What I can do is share some of the things I found about two or three years ago when I went on the same quest as you.
There is a whole subgroup of DIY folks who modify portable air conditioners to fix this by adding a second hose.
Luckily there are also a few options available for people that don't want to go down that road.
Mobile aircos with dual hoses:
Portable split unit solutions do excist. But these tend to be expensive or have other limitations.
One last option I want to mention is the American style window air conditioners. I have found a few of them available in the Netherlands, but only from shady sellers. However, if you can find one from a reputable seller and you actually have a suitable window I would go for that option.
I'm pleased to see the Technology Connections video. I had intended to link it myself. That channel is really one of YouTube's true gems.
Haha, same. That video brought me to that channel and also made me regret all the years I used a one hose AC when I used to rent.
Thanks a lot! Proper split systems probably be possible as I'm up on the fourth floor with nowhere to mount anything outside except for a narrow metal windowsill, but the inventum one looks promising
Relevant Polandball comic
Good to know! From what I could tell they’re out of my budget anyway, but thanks for the warning
I have the Trotec PAC 4600 and while it's quite efficient and does have wheels, it is HEAVY. If you need to move it around to store it, lifting it is going to be a challenge (you need to be at least two to carry both units). Also you may need to empty out the water reservoir if it is very humid outside. It stops working if the water reservoir gets too full.
Edit: also the indoor unit is quite big and bulky, much larger than the usual mobile units you see on sale. Outdoor unit isn't small and compact either, not too far from the size of a conventional outdoor unit. Need to keep that in mind when you put it away.
One thing that I don't see anyone suggesting is finding ways to keep the sun from heating your apartment in the first place. Not all of these options may work if you are not on the ground floor.
I live in a small detached backyard apartment in the US, so I have a small patio. I bought an umbrella that I keep open in the summer that shades my western facing windows. This doesn't help a ton for the air temperature midday, but it helps a ton at night. Your building absorbs the sun's energy and heats up the walls, roof, and floor if you don't shade them. When I have the umbrella preventing the sun from directly shining on the exterior wall and from shining onto my floor, my apartment cools down much quicker once the sun sets. Without the umbrella providing shade, it can take hours for my apartment to cool down once the sun sets.
If you can't have any exterior shading, you can upgrade your blinds. Cellular shades can prevent the sun from directly shining through your windows. Cellular shades have an air pocket in the center, so when the sun hits them, it heats an interior air pocket instead of being able to radiate the heat further into your apartment. If you install those on at least your western facing windows, you can stop the sun from heating the interior of your apartment at the time of day you want things to start cooling off.
Fwiw, this is the normal way of dealing with heat in a lot of central Europe (you should see how intense some German buildings' blinds are!), and I think it's what OP meant when they mentioned most people just try to keep their houses from getting hot in the first place. It is a good solution absent AC, but it requires your insulation to not be shitty.
I have shitty insulation too. I live in a converted 2 car garage. The exterior shading is what makes the big difference for me. It's feasible to do that for my apartment, but I know that wouldn't be possible for everyone.
This is main thing to fight summer heat for us (I'm in Czech Republic, central Europe). We have blinds that are metal shiny in color, it seems they are pure aluminium coated in some transparent thing. They kinda work like mirror, I would say even better than white ones.
Still - we get high temperatures inside, 25-27 degrees Celsius. It really is about managing the heat than foghting it - don't open windows until outside temperature is good (may be even as late as 22 o'clock) and shut them down again right in the morning. If temperature inside is high, we may even open a window fully (like 1,3m^2 of surface) through the whole night. Or just run good old fan to circle the air in the room.
As a precaution, ideally one would want to shade the window (or even wall) from outside. Maybe OP can open the window and install some kind of temporary ... cloth? ... hanging from the window frame over the glass. The worst thing is OP seems to be in rented appartment = no permanent solutions.
Seconding cellular shades, Ikea sells some blinds like this and they're a godsend for us! Keeping the blinds down during summer has made a big difference. A couple of quick and dirty solutions:
One better for sleeping on really hot nights is to wrap the frozen bottle in a towel and pop it in your bed. This has allowed me to sleep in a pinch on +30C nights.
As has dampening a sheet to cover myself with and turning on a fan.
I'm personally aiming to just die melting, as my apartment doesn't even have windows that open so a portable AC unit is out of the question. Luckily we've got that brand-new Neubau insulation so the German method of frantically covering all the windows at dawn works better in our case.
Wait, your windows don't even open? Is that pretty normal where you are? That would be completely unheard of (and I think illegal) where I am.
I can’t imagine living in a house and not being able to open the windows when it’s nice outside
And that’s coming from someone that lives in Texas (there’s maybe live 6-10 days in the year where I’d open the windows)
My apartment has a big balcony, so rest assured I get plenty of fresh air during the one week of good weather we get in Berlin 😆
Yeah, pretty normal for extremely energy efficient houses. There is no need to ever open a window (room ventilation is automated, and all escape routes are planned in advance - they might include a single window you can open/break).
The advantage is that you can build well-insulating windows a lot cheaper if they can't be moved and don't need seals.
Houses, yes, but that commenter said apartment. While the same concept could apply, I guess I've just never seen apartments like that (not contesting they exist, just saying it's alien to me). I apparently have a new topic to go into a wiki hole on, thanks!
Wow, I'd absolutely despise that. I hope there's at least some way to let some fresh air in.
At least in my case, I have doors that lead out to my balcony that can be tilted open for ventilation (as well as opened fully to access the balcony) as well as a special ventilation system that allows air transfer when everything is closed. I don't know the details of how the ventilation actually works, since I'm just renting, but for me it's just a small thing on the wall that I never notice except if it gets super windy outside, in which case it makes some vague noises. I can confirm our apartment is very well-ventilated compared to our previous one though.
Yeah I previously lived in a new energy efficient apartment building as well. I had windows that opened, but the apartment had vents fitted on a few exterior walls to allow some amount of air transfer even if the windows were shut. There was also a central fan in the apartment that would exhaust the air in the apartment so the wall vents would bring in more outside air.
It was pretty nice. The electricity bill was only $30 a month for a 1200sqft 2bd apartment with 3 people living there. In California, $30 a month is very low for that many people in similarly sized apartments. My previous 600sqft studio apartment was $30 a month for just myself.
Yeah I'm not super worried when it comes to the windows between the ventilation and the balcony, plus I like the brightly-lit effect of floor-to-ceiling windows.
There's plenty of fresh air, there's a ventilation system that takes the "stale" air out of the rooms and puts in air from outside. The heat pump usually transfers the temperature of the outgoing air onto the incoming air, and controls for humidity.
The energy exchange between incoming and outgoing air that you're referring to is called "energy recovery ventilation," and you can read more about that here and here. Awareness about these systems has been slowly spreading in the US, but it's kind of starting to pick up its pace - much like the increasing popularity of heat pumps. However, ERV systems can be more difficult to "retrofit" or "backfit" to existing homes, particularly if existing ductwork can't be used for some reason.
My apartment has floor-to-ceiling windows! Each room with them has a door out to our rather-large balcony, which we can open the normal way or tilt open upwards for just ventilation. But the windows themselves don't open.
Aaaaah, that makes a lot more sense.
De'Longhi makes compact air conditioners. They're sold everywhere in Switzerland, e.g. Galaxus. If you're not to sensitive to noise, you should be able to sleep while it runs in silent mode.
The tube goes out the window, and De'Longhi sells window covers even for "door style" windows. It's basically a piece of fabric that runs along all three sides of the open window, and the tube goes through a hole in the fabric.
If you're sensitive to noise, you need a "split system", which has a second device sitting outside your window and the tube connects to it. It contains the compressor, and so the device inside is much quieter. Those are less common for rental apartments, and often require you to mount the thing outside the window to the wall somehow. Also usually more expensive. A single unit compact system is several hundred bucks, a split system is often several thousand.
Ha! I'm assuming you're German swiss? Maybe it doesn't make a difference.
Allow me to introduce you to this comic, which made me understand Switzerland
Good to know! I can see the reason, every back alley in south east Asia is filled with the constant low chatter of dozens of small AC compressors of all the surrounding buildings.
I have no experience with this, and the reviews of this particular one in amazon are mixed, but I am posting it because it is different than the other solutions that have been suggested and might be a starting point for more research. It is a mat for the bed that circulates water to cool the bed.
https://www.amazon.com/Adamson-B10-Aqua-Mattress-Sleepers/dp/B0C2CRPM5P
So, a few simple things to consider. Keep in mind this will purely address comfort, not cost effectiveness.
Cover your windows with aluminum foil, shiney side out. Reflecting out the light in the summer time will do far more than most anything else. If you're feeling ambitious and you get a lot of direct sun on some walls, you could probably get some substantial benefit by hanging foil quilt insulation I'm betting between tape, rope, and some cheap caulk you could do so in an easily removable way.
Speaking of, seal all the largest wall and floor gaps with caulk, especially along the baseboard and window sill. You probably don't want to fully seal off unless you have some air coming in from elsewhere though.
A dehumidifier will do wonders for comfort if its a humid heat. It won't cool the room directly, but half of the benefit of air conditioning is that it removes humidity from the air. If you pair it with a humidifier (like hanging a wet towel on the other side of the room with a drip pan under it), and make sure the drain hose just goes straight out a sink or tub, you can get a lot of benefit. Make sure you get the most powerful one in your budget, in the USA you can get ones that cover entire 4br homes for < $400, it'll get the job done faster and just stay off when humidity levels are low enough.
If you have a ceiling fan, make sure that it's pushing the air down. This causes the cooler air on the floor to push up the walls.
As a hypothetical aside:
I wonder if they make a portable heat pump water heater, in the same vein as a countertop dishwasher. Something you could screw in to say your bathroom sink and then out to your shower faucet. They work by extracting the heat from the air into the water.
Are you trying to say that running a humidifier and dehumidifier in a room at the same time will cool it down? I have not heard of that being done, but I can see how it might work.
Not a powered humidifier mind. Just a source of moisture to evaporate into the air once humidity is < 50%. It might do nothing since at lower humidity your sweat will be the humidifier. You could just mist your body too.
It's the kind of thing that is dependent on trial and error.
Ah so a swamp cooler and then a dehumidifier to get rid of the humidity
Correct. A swamp cooler is just an evaporative humidifier. The dehumidifier itself will get warm, so there may negligible benefit. But lowering humidity to the point your sweat evaporates will do a lot.
A basic swamp cooler one can be made with a cup of water, a paper towel, and a AA battery fan.
Purely on thermodynamics, this cannot be the case. If you've got two devices doing work, some (plenty) is escaping as heat. A dehumidifier is most likely running a compressor, which is a relatively energy-intensive device. A humidifier is probably a transducer, which doesn't draw nearly as much, but still not nothing. If it's a forced evaporative humidifier, it'll be chucking out heat like nobody's business.
Unless you're doing some work and exhausting some energy outside the room, you're going to heat it up. That's why those portable aircon units (often) have an exhaust pipe to trail out of a window (and if it doesn't, it's a scam!).
Yea i probably shouldn't have said 'humidifier', because people assume that means 'another powered device'.
Powered humidifiers are a bit of a scam that will easily over-humidify a space. You just need some water with something to wick it to a wider surface area. If you have forced air or a fan elsewhere in the room, you don't need anything else.
And yea, the dehumidifier itself will get warm, but the fact that you'll be able to sweat again makes up for it.
Does the foil have to go on the outside of the window or can it be on the inside?
Doesn’t really matter except that on the outside it will be exposed to weather. You want that shiny stuff to stay shiny so as long as you clean it then I guess it should be fine. Inside seems easier overall.
If you have insulated windows, put the foil on the outside. The heat radiation won't come to the inside of the window in the first place.
Inside works fine.
We used to do it on the inside of the window with a cardboard backing. This both absorbs whatever heat might get through the foil and makes it easier to remove the foil in a way that's usable again later.
I'm no expert, but possibly a swamp cooler, depending on how dry it is where you live (the dryer the better)
I used to have a box fan in my window, but I wouldn't do that unless you have a screen to keep the bugs out. If you do this route it's best to keep the fan about a foot away from the window for optimal airflow
As someone who's had to deal with mold in a rented flat in central Europe before, I'm gonna advise against a swamp cooler. It really isn't dry enough in the summer here for them to be effective, and a lot of these buildings do not have good enough ventilation to avoid fungal problems.
Zürich is next to a lake (lake Zürich).
This is what I used to do without AC and it get pretty hot here (100/38+). Covered all my windows during the day and set up a push/pull fan configuration in the evening. I still had to sleep in basically nothing but it got me through grad school.
If you can afford/setup some type of AC unit it would definitely be much better.
Maybe try cooling down your body instead of the room?
Easy electrolyte formula
I know the swiss people hate running air (durchzug) but where I live only rich people have aircon, everybody else just has a (good) fan. once you get used to it, its nice.
Oh I bought a fan a long time ago, it's the only reason I'm still alive to write this post, but it's not enough to be comfortable
Also Zürich based and having the same intolerance to the heat, made worse by living in an attic flat, getting the sun on all sides of the roof. I do have the possibility to make a cross breeze through the flat to help cool it at night, but sounds like that isn't feasible for you.
I looked into it last year as well but couldn't settle on an AC unit to suit the awkward windows here. I did see some posts where people cut out a glass shape to suit the window and a hole for the tube, there's also window kits to attach to the window directly as another commenter mentioned.
I did find closing the bedroom door a while before sleep and sticking on a humidifier for a while to help slightly, but that may be more specific to me as I find the air very dry here, coming from a country that rains a lot and is usually above 70-80% humidity all year round.
I'm basically looking for another flat outside the city that isn't an attic so I don't have to deal with it again this year.
Lookup "DIY copper pipe air conditioner". Basically a box fan, a bunch of thin copper pipe, a water pump, some kind of insulated box and either ice or dry ice turns into an A/C unit. Bringing ice in from somewhere else keeps your freezer from heating your home to make the ice.
It may end up just having a source of blowing cold air rather than cooling your entire home, but it's better than nothing. Just be careful about leaks and condensation, might put down a tarp or plastic sheets just to be on the safe side.
Bringing from outside is key. Otherwise you're fundementally just wasting power.
Ice based air cooling is a pretty futile thing, in my experience. Ice melts very quickly in the summer heat and it doesn't actually displace that much energy, so it's only good for very short periods of time.
Greetings from Greece. I would consider a large slow-moving ceiling fan. Also, shutters are much more effective than blinds to keep the sun out.
I'm not entirely sure what the difference between shutters and blinds is supposed to be. Mine are greyish plastic panels that can be rolled down on the outside of the window and that, when fully rolled down, entirely block out the light.
The issues I have with just keeping them down all day is threefold:
If they are on the outside of your window, they should be fine. Keeping the sun out is very important. You should go out, not let the sun inside.
You should air the room as much as possible, if the outside temp is lower than the inside.
Also, 27-29 Celsius is what I consider acceptable in-house temp for our summer. In July we usually face up to 30-33 at night inside. Above that, AC is the only solution.
One small trick: Sprinkle a few drops of water on a curtain/sheet. It will evaporate and cool the room a little when it does so.
We had horizontal sliding glass windows and any ac unit we could find was for vertical windows. My husband is pretty handy and used wood to fill up the window where the ac unit wasn't (and to help hold it in). Dunno how handy you are but if you and the house owner are fine with an ugly modification that could easily be removed when you move you could try doing something like that with the ac. Downsides though is it is ugly, your window would be permanently opened and you wouldn't be able to see out of it, you couldn't actually open the window to the outside anymore (it's opened but filled). I mean with the sliding glass I still got some window cause we only needed to open it up partway to put the ac unit in where as door like opening ones will have to be wide open to accomodate the ac unit.
Not a great option but thought I'd mention it in case you still liked it better than the portable one (and the window units do work better I believe).
I have set up reflectors outside my windows to keep the sun out with great success.
In the US we have foam boards that are covered in mylar (reflective metallic coating) and are 4’x6’ (122cm x 182cm). I leaned a few of these up against the windows that got the most light and it kept the temp in my house (especially my bedroom) much cooler. If the boards aren’t available anything white or reflective could work.
A word of caution: make sure that the light isn’t reflecting onto the ground or anything that could even possibly catch fire.
With that said a board leaning against the wall at 80 degree and pointing out to nowhere will be fine.
I have a set of tasks for when it gets dangerously hot. I lived in the deep south of the US for a decade. Our city lost power for non essential buildings for over a week when it was over 110F/43C. My house had no power for an additional week because I lived on an island.
Reflective tape on the windows from the outside. It's not glued on so it can be removed when you return the apartment with minimal effort. Using the inside variant gives you about 3-5°C. Outside variant should help even more. Blinds are the best, but it's hard to install exterior blinds on a property that's not yours. Possibly combine reflective tape and interior blinds.
Huge problem is your own body heat and possibly your computer or TV set. It's pretty easy to heat up a room in winter by playing a demanding game. Humans produce 100-200 Watts of heat, your desktop up to 400W. Large TVs easily 200W. In summer, where the heat cannot escape outside, the temperature rise from all this is even faster.