Orientation of windows, what are the factors to be considered

The orientation of the doors and windows is one of the factors to be considered when designing energy-efficient spaces.

In fact, the orientation and position of the building and windows affect the lighting of the rooms and therefore the electricity and heating consumption.

With a view to global well-being, bio-architecture deals with this issue not only as a factor of energy efficiency. Infact, it refers to oriental disciplines by identifying in the right orientation also a factor of living comfort and, more in depth, of psycho-physical balance of each individual.

Precisely from the East, which is much more sensitive than us from this point of view, we have borrowed our studies, according to which a certain position of the rooms and their furnishings can favor rest and concentration, serenity, etc.

There is no doubt that the orientation affects the energy saving of the house.

According to some variables that precisely define the characteristics of the place, we choose the best position for the windows and doors and, when this first step is not possible, we decide on the best type of window based on its orientation.

We want to explain how this choice is influenced by:

• climatic area;
• exposure to bad weather;
• natural or artificial shading;
• internal layout of the rooms;
• design needs.

Taking these variables into consideration, we will realize that the common criterion of orientation to the south is not sufficient to favor solar radiation during the hottest hours. It is also necessary to take into account the geographical place where the building is located, the presence or absence of vegetation or many nearby buildings and all the construction and design needs that sometimes do not allow you to fully comply with the orientation and position criteria.

So we must know immediately if our need is to retain heat or reject it, if we have to heat the rooms or cool them, in what urban context we are and how to arrange the rooms.

Local climatic data

The local climatic data of the place are among the factors that most affect the orientation of the fixtures.

In fact, according to the climatic area, needs vary. In hot places our concern is to protect the interior from overheating. Instead, in places with a cold climate we must look for solutions that allow us to keep the heat inside the buildings for as long as possible.

It would be too simplistic for a designer to define the Southeast as the perfect position for a window without taking into account the local climatic data.

We investigate the various climatic zones to better understand.

Where the climate is temperate, as in our country, temperatures are generally mild, with moderately cold winters and not excessively hot summers. In our case, the general lines suggest installing large windows to the East and West, enhancing the insulation to the North and South. In this way we are able to preserve the interiors from moments of maximum cold and maximum heat.

In humid warm climate regions, ventilation plays a key role. Therefore we tend to choose the East-West orientation to ensure constant air flows from these directions.

Where the climate is hot and dry, it is necessary to prevent sunlight from reflecting on walls and floors, multiplying radiation and overheating. Installing north-facing windows can prevent this from happening.

But let’s continue to analyze other factors that affect the choice of orientation of the windows.

Internal layout of the rooms

The internal layout of the rooms also requires careful analysis so that the home or office is truly energy efficient.

In fact, choosing the right orientation of the interiors means designing the spaces so that solar energy reaches them appropriately according to the climatic area.

Once again we are in a sector widely covered by green building, which always places the well-being and liveability of spaces at the center of its attention, according to a green perspective.

In this sense, the most lived-in rooms, which require more lighting, such as the living room, kitchen and dining room, must be oriented towards the South or South-West, to benefit from natural lighting for longer. In this way we favor savings both on heating in winter and on lighting.

On the contrary, the bathroom, bedroom, closets, stairwells can also be placed in the darkest areas of the house, to the north, and take advantage of artificial light in the few moments of use of the room.

More precisely, it is better to place the bedroom towards the east so that it is irradiated by the first rays of the sun.

However, it is not always possible to support these general parameters. The client’s needs and design needs may require a different location of the rooms and the use of shading systems or thermal break windows capable of maintaining the best temperatures inside the rooms.

Presence of buildings or vegetation nearby

The presence of buildings or vegetation nearby is a factor to be considered in the design phase or at least in the installation of the windows. In bioclimatic architecture, the vegetation near a building plays a crucial role for the living well-being inside it. In fact, it naturally absorbs carbon dioxide and releases oxygen, with a series of benefits for indoor environments:

• shielding from solar radiation;
• filtering of polluting dusts;
• steam production;
• regulation of the evaporation of rainwater;
• internal heat reduction;
• decrease in urban overheating.

So vegetation plays a very important role in generating optimal thermal conditions in homes, offices, commercial and public buildings.

In addition to shading and making the air healthier, it can favor or prevent the passage of air and perform the function of a natural acoustic barrier.

The presence of tall buildings also influences the living well-being of the surrounding houses. A tall building can act as a shading unit, but it can also prevent the passage of sunlight, forcing the long use of artificial lighting. But the same tall building can protect from winds, creating a kind of barrier. For this reason, the presence of buildings is a factor that should not be underestimated in the design phase.

Of course, also in this case, as in the previous ones, the design needs could lead to choices that are not entirely in line with the theories of green building. They can be adapted to the situation thanks to the use of materials and technologies capable of making the windows perform in any thermal condition.