Why is it that the portals of buildings are cooler than the actual houses?

Summer is here and many people realize how fresh their portals are when they return home. This thermal difference becomes even more apparent during a heat wave, making it almost impossible to sleep there. Although each portal is unique, this phenomenon has some commonalities.

The portal is often a darkened place. It is often located on the ground floor and has many elements that provide shade. Arcades, overhangs that protect against the rain or terraces on the upper floors are just a few examples. These elements reduce the risk of solar radiation which can lower the temperature.

These spaces could also have shade-producing elements outside the building, such as trees or street furniture. These distant obstacles can help lower the temperature of these spaces in summer without shading the upper part of the buildings.

Other spaces or elements may be in direct contact with the main entry of the building. If there is no basement, the land is an example. It is generally more stable throughout the year. Non-habitable properties include storage rooms, meter room, boiler rooms and garages. There may also be commercial stores that condition premises during business hours. They all help to temper it.

We don't refrigerate our air during the day because we aren't usually home. We leave the windows wide open so that the outside air can escape. It causes the temperature to soar.

The entrances to buildings are often covered in noble materials. This is a common decoration that uses stone or ceramic materials such as tiles and marble. This can also reduce the temperature at the entrance of the building and keep it cooler.

The chimney effect, which is caused by stairwells, also has an impact on the temperature of these areas.

Hot air is lighter than cold and escapes through the staircase, reaching higher floors. Stratification is the result of heat accumulation in the upper layers of air. This air will rise if it is not contained. The main entrance or other entrances allow fresh air to enter, replacing warm air and keeping it cooler for longer.

These spaces don't radiate heat from the sun by not being in direct contact with them for prolonged periods of time.

Heat transfer occurs from one residence to the next. Older houses are often not well insulated. They are often better insulated against uninhabitable areas. This means that coolness from the building access doesn't easily pass through the dwellings.

Other complex effects, whether they are anthropogenic or natural, include extreme weather events (heatwaves) and the urban heat island effect. These tend to increase thermal differences between different spaces.

Access spaces for residential buildings (portals and hallways) have a number of features that make them cooler than the rest.

They could be used as climate shelters. People who are vulnerable to heat could use many of these accesses. They would be particularly useful during heat waves or at central times of day.

People with heat stress and fatigue can take a break or rest for a few moments to relieve their symptoms. The portals could be used to give them more life. These access spaces, which were once meeting places for neighborhood social gatherings and community meetings, are now treated with individualism, social mobility, and the same care as non-places in residential buildings.

This new function could help public health by transforming access spaces into cool rooms. Cool rooms are so necessary during periods of heat suffocating.

This article was published in "The Conversation".