Hey everyone, I live in a WG in Aachen. My room gets extremely hot during summer. I am a bit more sensitive to heat than a normal person and this makes my stay in this room extremely uncomfortable. But except for this, the WG is pretty great and at a nice location, so I don't feel like moving from here.

The main problem is the 4 large windows directlt exposed to the sunlight (see image). There are blinds, but while they help to restrict the light they do nothing against the heat. On one warm summer afternoon, I checked the temperature of the window glass using an IR thermometer and it was 48°C. 4 large windows like that radiate the hell inside and I get cooked. Now, even if it is cold outside like 18-20°C, if there is sunlight my room gets hot. I can solve this by opening the windows as cool air comes inside. But during summers this doesn't work as the air outside itself is hot.

I spend my last summer entirely in my office until 21:00 when the sun went down. My boss was compassionate and he even gave me an extra key for the office. But I don't want to do that this summer, and I really need to find some way to reduce the heat.

I was thinking of foils which can be stuck on windows, but I don't know which to choose. Also, should I stick them outside or inside? I heard that if you stick inside, there is a chance that the double glazed window might break? What other options are there? I don't care if it also restricts the light and the room becomes dark.

I would also like to know if there are any professional guys in Aachen who can help me with this.

by Round-Excitement-377

9 comments

  2. Of course, the blinds hardly help against the heat. Because the sun’s rays are already in the room before they are holding back by the blinds. So for an effective solution, you would need something on the outside of the window. The best solution would of course be roller shutters. But as it’s a room in a shared flat, you won’t be allowed to install them.

    You’ll also have a hard time with other “fixed attachments” because it’s not your property.

    So I’m afraid the best solution in your case is to buy a mobile air conditioning unit.

  3. You can try sticking the tinted foils outside the window so they reflect off most sunlight.

    Also may be invest 8n an AC unit. I see no other option than to shell out 150 or so € and cool off…cheaper than moving apartments I assume.

  5. Im sure you are already doing it but just to make sure: at night open all windows, best all of the flat. Let it get as cold as possible to cool down the walls and so forth. During the day windows closed as long as its still cooler inside than outside. 

  6. And another tip to make yourself cooler, put your feet in a bucket with cold water. 

  7. Unless you can change anything on the outer side, there is not too much you can do, unfortunately. You can try to keep hot air outside for the first few days by keeping the windows closed during daytime and opening them once it gets colder over night. However, after a few days, this won‘t help anymore as the heat will also come through the walls etc.

    Once the hot air is inside, windows are closed and you spend time inside the room, the humidity will go up simply due to your presence (breathing, sweating, …) and this will make it even more unbearable.

    To make it somewhat comfortable, open the window and try to put a fan in a good location so that there will be a bit of air circulation, which is going to cool you down a bit. This won‘t change the room temperature itself, but it will feel more pleasant. Think of it as if you were in a desert while it‘s 35°C (will feel more pleasant due to low humidity) VS in a rain forest while it‘s 35°C (will be unbearable due to high humidity).

  8. You can buy mylar sheets (usually sold as survival blankets or the like) and line your windows with them. They’re very lightweight and reflective. This reflects a large portion of the energy back out – even more than white blinds. Additionally, even if the glass gets hot, the mylar will help reflect that out as well. It’s not perfect obviously, but it’s a much stronger effect than just blinds or curtains.

    There are a few downsides: the mylar is fragile and rips easily, you must set it up and take it down every day (if you want to open windows at night) and it blocks a huge majority of the light (which is what has the heat so this is kinda wanted).

    If you’re very careful, you _might_ even be able to wrap the outside of your windows in it instead, keeping the heat entirely outside. I would kinda expect it to rip and tear though, especially if there’s any window.

  9. If you don’t want to stick foil at the windows try white fabric at first. An old table cloth or something like that. Put it over the open window(outside )and then close the window so it clamps. It’s important that you reflect the sun rays before they enter the room and the window.

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