Ventilation during heat waves, how can we combat them?

The summer months can be a real ordeal when heat waves arrive, those periods when going outside can be unpleasant and stores and shopping centers become crowded as people seek refuge from the heat. At home, those without any air conditioning solutions used to leave, but since the late last century, air conditioning units have become popular. However, their consumption is too high and today new alternatives are being sought. One of these is the use of ventilation during heat waves, which can assist us in a variety of situations.

Mechanical ventilation is the best way to refresh the air indoors without the need to open windows, thus improving our health. With the necessary air exchange, we prevent the formation of germs in the air, the retention of humidity, and also the elimination of stale air and other pollutants. During heat waves, it can also help alleviate the harmful effects of high temperatures, in addition to providing us with greater comfort.

Before considering the necessary air conditioning during heat waves, we must prepare at home to manage them better. The following is recommended:

• Close the windows, whether you have forced ventilation or not. And during sunny hours, use blinds. You can open the windows at night when it cools down.
• Avoid the sun. Try to stay indoors between mid-morning and mid-afternoon, and do not sit near the walls where the sun's rays hit.
• In addition to blinds, you can use reflective materials on the windows. Light-colored windows remove heat better than dark ones.
• If you have no air conditioning, taking baths and wetting yourself with water always helps. Of course, drink plenty of water and avoid alcohol. You can drink soft drinks, but watch out for sugar.
• Always have water at home.
• You can identify which room is the coolest in your house and prepare it to stay in.
• At home, wearing light clothing also helps.

Assuming you have an air conditioning unit, it is possible to eliminate heat by introducing cold air. Unfortunately, this method - which is very old - continues to be very low in energy efficiency, and it does not renew the air in the home. For that, a mechanical ventilation system is necessary.

Forced ventilation can eliminate the indoor air and replace it with outdoor air. In this way:

1. It removes the warmer air inside the house.
2. It extracts humidity, which is a significant source of thermal sensation.
3. It carries away smoke and toxic products.

Even so, can we cool the home with a mechanical ventilation system? It is possible, and with very good results thanks to heat recovery units.

Double flow systems for ventilation during heat waves

The double flow ventilation is the most practical solution for air renewal indoors. Thanks to it, it is possible to extract air under less than optimal conditions to introduce quality air. For this, it utilizes two separate duct systems, one for extraction and the other for supplying air. It can be centralized or decentralized.

To use ventilation during heat waves, it is essential to have a heat recovery unit, as it would facilitate the following:

1. The poorer quality air, also of high temperature, would be uniformly extracted by the extraction system. With this, humidity would also be removed, which increases the thermal sensation and discomfort by making us sweat more.
2. When introducing air from the street, it may indeed be very warm, but this air would pass through a heat recovery unit, which heats the air in winter and cools it in summer. By letting this outside air in with the cooled air, a cooling bypass effect would take place and we would manage to cool the rooms.
3. If additionally the mechanical ventilation system includes a dehumidifier, in high humidity areas like the coast, the comfort could be significantly improved.

With this system, we can cool our homes at minimal cost since the ventilation system only consumes the energy that each of the fans needs. How much can it cool a room? It won't be difficult to achieve a comfortable 26°C without using air conditioning systems, as long as the house has minimum thermal insulation.

Even when air conditioning units are available, ventilation during heat waves can help reduce air conditioning expenses, as its use will be much less necessary, at lower power, and for very little time thanks to the support of mechanical ventilation.