Heatwaves: shut the windows to keep out the heat

During the summer season, the heat inside the house can become oppressive and be the cause of various discomforts.

windows closed during heatwaves

There are many ways to protect oneself from the heat, including the use of fans and air conditioners.

Heat waves are one of the consequences of climate change and the use of air conditioners, while making the temperature inside pleasant, only increases the temperature outside.

Those who want to save on electricity, while maintaining a livable temperature inside the house, can make it dark inside by closing shutters and windows. It may seem like a nonsense to close the windows of the house during the hottest hours of the day but, in fact, this is perfectly logical.

The heat inside our homes is caused by two factors:

  1. the hot air coming from outside
  2. the direct sunlight that penetrates through the windows

To ajar the shutters but leave the windows open would certainly create a shading inside the house that would increase the comfort but the hot air or, even worse, hot-humid air present outside would tend, however, to penetrate inside the house.

It goes without saying that if, on the contrary, we left the shutters open but kept the windows closed, the direct sunlight on the windows would create inside the house what can be called the "greenhouse effect", or the same unbearable situation that is created in the closed cockpit of a car left under the sun in the summer.

It is in all cases advisable, therefore, that the glass surfaces, during the period of direct insolation, are adequately shielded so that they do not end up constituting, themselves, a multiplier effect of heat.

The best solution is therefore to totally close both the shutters and the windows; in this way, a sort of air chamber is created between the shutters and the windows, insulating the inside of the house during the day.

At this point, if you have to stay at home, you will necessarily have to turn on some lights and you are legitimately wondering if this method can be considered an acute ecological choice and savings; well, the answer is both negative and positive.

This is an acceptable compromise between those who want to save themselves from the heat and yet not have to use an air conditioner.

Keeping light bulbs on, in fact, certainly implies an energy consumption but it is a much lower energy consumption than that of an air conditioner/fan.

This will be even more true if we take care to follow common sense and keep the rule "one man = one light bulb", i.e. keep the light on only where it is needed and only when we physically occupy a room.

The advice, if you have not already done so, is to replace all the old bulbs with LED bulbs.

Many people will not like having to stay "barricaded" inside the house without seeing the light of day and then you can resort to a further compromise downward that will increase the internal temperature of a little but will allow at least to have a portion of the house not completely in the dark.

As we were saying, one of the causes of the heat perceived inside the house is due to direct insolation, but once the sun has moved and does not directly irradiate a surface, one can try to reopen the shutters while continuing to keep the windows closed.

In this way the hot air will continue to stay outside but at least on the side where there is no more direct insolation you will be able to enjoy natural light and this, by keeping the internal doors of the house open, could also be enough to maintain a minimum of visibility in all rooms.

So when can the windows be opened?

Once the sun has set and until shortly after its rising the outside temperature is sufficiently pleasant (or at least always more pleasant than during the hottest hours) and therefore during this period, which essentially corresponds to the phase "sunset-night-dawn", the windows can also be kept open.

We are perfectly aware of the fact that, with the times that run, it is not the best security to leave the windows open during the night even if you are at home, but this is a problem that has little to do with the summer heat and a lot to do with security, unfortunately.

In any case, we take into account that an air exchange is necessary even if we have adopted the daytime dimming.

Even if we have left the sun out during the day, it has not ceased to heat the outer walls of the house and they accumulate heat and then give it up progressively during the night; and this happens even in modern houses where the walls should be well insulated.

The transfer of heat accumulated by the walls during the day will therefore be felt during the night if we do not take care to ventilate the rooms.

If we really want to adopt a solution that takes into account all aspects, savings-comfort-safety, the advice is therefore to darken the house during the day and use a fan / air conditioner at night, so as to ensure a good night's sleep without exposing us to the risks of open windows.

Finally, there is also another very valid alternative which consists in applying special anti-sun films on the windows which allow to reduce solar energy up to 80%.

DIY Editor
Do-it-yourself enthusiast. I started with the renovation of my flat and then I changhed this passion into my job.