Sun Exposure

If you want to buy a house, solar orientation is one of the factors that should be considered for the sake of your comfort and the value of your investment.

Exposição solar nas casas

The ideal is that the most used rooms of the house are oriented in order to capture the maximum hours of sun exposure (in the regions of Portugal with cold to moderate weather), in order to improve energy efficiency and maximize natural lighting .

Climate and sun exposure in Portugal

Portugal is characterized by benefiting from a temperate climate and mild temperatures, being influenced by its maritime exposure to the Atlantic and Mediterranean, which contribute to hot summers and humid winters . But the climate and temperatures also vary depending on latitude, altitude and proximity to the sea:

  • Influence of latitude: the South is hotter than the North;
  • Influence of the sea: the coast is not so cold in winter, nor so hot in summer;
  • Influence of the relief: the more mountainous areas of the North and Center are colder;
  • Influences of embedded valleys: namely in the Douro, where summers are very hot.

It is therefore important to take into account the specificities of each region because, despite the fact that the Portuguese territory is not very large, as its shape and topography mean that between the North and the South, the coast and the interior, the degree of humidity at the thermal differences are large.

  • Further north, in Minho , the climate is colder and more humid in winter.
  • In the northern interior of the country - Trás-os-Montes, Alto Douro and Beira Alta - as they are more mountainous regions, the climate in general is colder and more humid, with periods of snow in the higher areas. In these regions it is preferable that the solar orientation is facing South , in order to benefit from the greatest number of hours of sun exposure.
  • In Lisbon, Alentejo and Algarve the summers are longer and hotter with temperatures around 35, 40 ° C. The humidity decreases as we move away from the sea coast, and in the interior areas, in the Alentejo, temperatures are very high in the summer.Thus, in this region, one should avoid orienting the most used rooms of the house to the South, with the East-West solar orientation being an adequate option;
  • Madeira benefits from a subtropical climate throughout the year, with mild and stable temperatures, while in the Azores winter is generally more windy and humid.

The influence of solar orientation in a home

Solar orientation of a house

The areas of the house facing each of the quadrants have specific particularities that are important to know, as the sun exposure conditions the comfort and the respective energy consumption:

  • North: side with low sun exposure, cold and humidity in winter, contributing to the divisions being very cold in winter and cool in summer. Depending on the house being located in a more northern region of the country, one can choose to reduce the number of windows mitigating the thermal impact ;
  • Rising (East): some sun exposure, especially during the morning when the sun is low. Very cool place in winter but very pleasant in summer;
  • South: the best side of the house, provides good sun exposure throughout the year, benefits from the low sun in winter. Para minimizar o sobre-aquecimento das divisões, especialmente na região Sul do país, é conveniente utilizar protecções solares do tipo: palas, alpendres, proteção de alçados, telheiros ou outros “obstáculos” de origem natural (árvores de folha caduca, etc.). Desta forma a casa continua iluminada e aquecida durante o Inverno, quando o Sol anda mais baixo, mas desempenha uma proteção importante no Verão quando o Sol circula em posição mais alta;
  • Poente (Oeste): as divisões orientadas a poente, beneficiam de forte exposição solar nos períodos da tarde, com sobre-iluminação nas horas de poente ou quando o sol se encontra em posição mais baixa, como no Inverno. Localização ideal para plantar árvores.

Sugestões para a orientação das divisões de uma casa

Sugestões para orientação solar das divisões de uma casa

Despite what has been said in relation to the specificities of each region of Portugal, here are some suggestions for a better orientation of the different rooms of a house:

  • North - This being the coldest area and with least sun exposure in the house, it will be advised for the garage , pantry , laundry , attachments and storage areas;
  • Source - With morning sun exposure, it is ideal for areas that despite being cooler in winter, are quite comfortable in summer, such as: workshops and atelier , gym , solarium , entrance hall , dressing room , kitchen / pantry , guest room , bathroom, etc.;
  • South - This is the area of the house with the greatest light and sun exposure, which makes it ideal for areas of enjoyment and leisure: swimming pool , bedrooms , dining room , terraces and balconies , entrance hall ;
  • West - Facing the sunset, it is recommended for rooms that need light. In warmer regions or during summer there will be an increase in temperature that can be compensated with, such as: rooms and social areas , office , library , corridors , stairs and circulation areas , balconies and terraces ;

Advantages and disadvantages associated with sun exposure in a home

This is aof the most important factors to consider when buying a house or preparing an architectural project, if you intend to build a new one.Some of the benefits associated with the correct sun exposure of a home are:

Improvement of energy consumption - Depending on the climate of the region where the house is located, it will be convenient to orient the rooms in order to protect those that are most used, from excess heat or cold. This way you will use less artificial heating / cooling methods, saving energy consumption and reducing gas or electricity bills in seasons with higher peak temperatures.

Energy Efficiency Certificate - This is a factor that reflects positively or negatively on the valuation of a home. Thus, a good efficiency index declared in the energy certificate (which takes into account the sun exposure of the property), can contribute to sell your home more easily and at a better price.

Comfort and health - Living in a house oriented to the north, especially in areas close to forest or mountains, will contribute to making the house more humid with the consequent problems that this can cause in terms of health in children and adults;

Valuation of a house - Those who buy a house do not always think that one day they may have to sell it, but if that happens, they may face increased difficulties, discouraging visitors who encounter a property with poor sun exposure, eventually having to lower the sale price to be able to close the deal.

What to do to lessen the effects of a bad sun exposure?

What to do to lessen the effects of a bad sun exposure?

Sometimes it is not possible to do anything about the solar orientation of a house, either because the orientation of the land or the implantation polygon does not allow it, or because simply the house or apartment you bought was built by a third party.But here are some tips to alleviate the negative impact of poor solar orientation:

  • Choose the most suitable rooms to serve as a bedroom, living room or office, depending on the time of occupation and the need to have more or less sun exposure, more or less heat;
  • Window frames and window glass are one of the most important sources of heat and cold transfer. Replacing windows with windows with better thermal insulation is a solution (eg Oscilo-Jamb windows with double glazing and thermal cut, allowing a reduction in thermal transmission between 40% to 60%). However, it must not fail to safeguard the issue of ventilation in order to allow air to be renewed.
  • If the house overheats, install suitable blinds / curtains to filter the sun, especially when it hits in the morning or at dusk.Alternatively, you can apply Sun Protection Films over the existing glass. These films insulate in winter and summer, filter solar radiation (infrared rejection up to 98%), allowing for a reduction in air conditioning expenses and an almost total absorption of ultraviolet rays.
  • If it is a house with a garden and has too much sun exposure, plant deciduous trees in order to create a natural curtain to reduce sunlight in the summer, safeguarding the winter period when leaves fall and more radiation is needed solar.
  • If you have walls with too much sun exposure or the walls of your house do not have the appropriate thickness / thermal insulation, you can request the intervention of a company specializing in Exterior Thermal Insulation (using, for example, the coating with acrylic).The application of this thermal insulation reduces moisture by condensation (molds) and contributes to improving the energy efficiency of your home.
  • If your house is cold and has a fireplace, consider installing a heat recovery system to take advantage of the fireplace's heat and heat the cooler rooms.
Updated on: 
8. September 2019
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