When choosing building materials, it’s important to direct your choice towards a solution that balances environmental and economic options. The best way to achieve this is to ask the manufacturer/dealer for some information about its origin, the impacts associated with its use and recommendations when it becomes an obsolete product – waste. Gathering information could include, for example, asking about the raw materials (whether they are renewable or not), which country it came from (if it involved a lot of movement/transport), whether the processes used in its manufacture are clean technologies, whether it has any hazardous components, whether it has an impact on the environment or public health, the material’s behavior (technical data sheet), what to do and what to do with the material when it becomes waste. There are other manufacturers who implement environmental criteria in the manufacturing process, such as adopting the environmental certification system for companies (ISO 14001 and EMAS). Any of these options guarantees that environmental aspects have been taken into account during the manufacture of the product and that efforts have been made to minimize them. To help you choose eco-products, take a look at our database of eco-products selected taking into account their sustainability assessment.

It is essential to check that the material we are selecting for use as insulation performs well (technical characteristics). Next, the impacts associated with its use must be assessed, both in terms of environmental impacts and public health impacts. To this end, you should always look for a material that has no negative effects on health (such as asbestos, which is considered carcinogenic). On the other hand, you should always opt for more environmentally friendly materials (made from renewable resources, produced using cleaner technologies, recyclable, etc.), such as cork.

When we want to choose the type of window frames to install, the question often arises as to what material to use? The key thing to consider when choosing a frame is undoubtedly its acoustic and thermal insulation capacity. This is decisive if we want to make a choice based on the quality of the solution to be implemented. The materials we look at here for window frames are wood, aluminum and fiberglass, although there are other alternatives. There are now some solutions on the market that combine some of the most common materials, such as wooden frames covered in aluminum on the outside. The choice of each of these materials often has to do with aesthetics or economics, as each one achieves very similar thermal or acoustic performance. You should always consider double glazing with 6 mm and 4 mm glass and a 12 mm air gap between them. So let’s take a brief look at the material in terms of thermal and acoustic insulation: Performance in terms of thermal and acoustic insulation: both wood and thermally cut aluminum and fiberglass frames have similar performance; In the case of exterior frames that are very exposed to large climatic variations, it turns out that better performance is achieved with the innovation of fiberglass frames.

Thermal insulation should be placed in the middle of a double wall, always close to the inside of the wall, or on the outside of a single wall. The question that usually arises in either case is whether the insulation actually runs along the entire wall. Often the insulation is placed along the wall, but when it reaches the structural elements (beams and pillars) it is interrupted, thus providing, in this uninsulated area, air exchanges with the outside (thermal bridges), which in turn give rise to condensation, promoting the appearance of mold. It is therefore essential to apply thermal insulation continuously.

When we talk about insulation material for buildings, we have to make sure that it is impermeable to water but permeable to water vapor, so that the building is protected but not asphyxiated, in other words, it is very important to let it breathe. And the reason is simple: inside any building, vapors are produced that lead to an accumulation of water, and if they are prevented from leaving by a waterproofing layer (preventing their diffusion to the outside), the vapor will find no other way than to return inside, in other words, it will produce condensation. When we talk about environmentally friendly insulation materials for buildings, we have to consider them according to their effectiveness in terms of the useful life of the building, as well as, and no less importantly, according to the life cycle of the material itself.

They are different construction processes. The double wall is equipped with an air gap between the two wall panels, the purpose of which is to keep the interior wall (which is in contact with the interior of the house) completely dry, concentrating the humidity coming from both the house and the street in the space in between, and it is essential that there is a construction solution in this space connected to the two walls that makes it possible to drain the water that penetrates there, whether from rain or condensation, so that the interior wall never gets wet. As well as being drained, this space must be ventilated. The simple wall is made up of just a single wall panel which, if insulated from the outside, is very energy efficient, keeps the temperature at the right levels and indirectly prevents vapor condensation on the walls due to excessively low temperatures. This method allows for a significant reduction in wall thickness and the possibility of adapting or modifying the exterior appearance of the façade.

Insulation is essential when we want to achieve an energy-efficient building. This is because there’s no point in heating a house when we have high thermal losses through uninsulated walls. In other words, the aim is to have the indoor air at a comfortable temperature and then maintain it. In order to keep it at a constant temperature, we can’t let it out, which is achieved by using insulation. Insulation should be applied on the outside in the case of single walls, or placed in the air gap next to the inner wall in the case of double walls. Let’s see: when we heat the air in an interior space, it heats up the mass that makes up the wall and gradually passes through it. When it finishes its journey, it comes up against the insulation that doesn’t let it out, keeping the wall warm and consequently the interior air at a constant temperature. In addition, applying the insulating material to the outside of the wall reduces the thermal amplitude of the wall, preventing excess heat from penetrating it (on hot summer days) or cold (on very cold winter days) and also protects it from atmospheric agents, thus reducing the deterioration of the material that makes it up. For these reasons, insulation should not be placed on the inside, as not only would it not protect the wall, but it would not allow the comfort temperature to penetrate it and be stored.

There is no doubt that the best and most advantageous orientation for a house, always taking energy efficiency into account, is to the south, since it allows both significant solar gains and total control of overheating through external protections. The ideal would be to be able to turn the whole house to the south, which is feasible if we’re talking about multi-family housing – apartment buildings, where it won’t be difficult to find some dwellings oriented only to the south, but when it comes to a house, the situation becomes more complicated, as there are many factors that influence the placement of openings in a building: the view, the need for ventilation and airing, as well as aesthetic factors. In this context, here are just a few suggestions for taking advantage of passive heating/cooling (using solar energy): Adjacent to the north façade, which in principle should be blind or contain the absolute minimum of windows, secondary outbuildings such as garages, warehouses, etc. should be oriented so as to achieve greater thermal protection. If the terrain allows it and the slope is steep, the north façade should also be protected by a slope or embankment. Thus, priority should be given to the south, to the main functions, i.e. the largest inhabited area, so that in winter the solar gains that are essential to contribute to better thermal conditions and well-being (health and comfort) can be ensured, guaranteeing that the south façade has the right to the sun in its entirety. Schematically, a possible orientation would be: – North: Garage, storage rooms, vestibules, circulation, with few or no openings to the outside; – East: Bedrooms, with small or medium-sized windows protected from the outside by vertical blinds or shutters, to avoid glare/overheating in the morning in summer; – South: common room, large windows, protected by external horizontal louvers or blinds and location of a greenhouse, if desired; – West: kitchen, office, small or medium-sized windows, protected by external vertical louvers or blinds, to avoid glare/overheating in the summer at the end of the day.

To begin with, you need to take this into account right from the design stage, as this is the key to having a more sustainable home down the line. First of all, in the preliminary study phase, you need to take into account the surroundings, in particular the topography of the land, so that you can take advantage of it, as well as the existing vegetation, bearing in mind that you should conserve it and take advantage of it if necessary for shading techniques, for example. Sun exposure is, if not the most important factor, a determining factor in the energy efficiency of the house. In the design phase, we should always aim for natural lighting in the living areas, balancing the proportions between openings to the outside (openings) and opaque façade surfaces. Passive heating and cooling (through sunlight) should also be promoted, achieved by opening glazed openings with solar exposure to the south, taking advantage of the northern orientation for sanitary facilities, circulation and storage rooms, and not neglecting the control of glare and overheating, especially on the east and west façades. It is very important that this control is carried out through solar protection placed on the outside of the windows (blinds, shutters, louvers or setbacks on the façades), to avoid the so-called greenhouse effect. During the construction phase, it is important that the insulation is applied effectively, insulating the house as a whole and continuously. There are, however, a few other factors that influence the house: whether or not there is water on the land that can be used for various purposes, the provision of double plumbing so that water from baths and sinks can be reused for flushing toilets. When planning a house, you should always take into account the area of the house, and consequently the proportion of land to be waterproofed, as well as good drainage of the water that would pass through the land that will be occupied. There is also the option of diverting the water to a tank so that it can be used for irrigation or other purposes.

Companies often invest more time and money in trying to convey the green image of their products than in real, effective environmental good practices. To this end, products are certified with seals that often claim to link them to nature without actually being environmentally sound, such as the image of a forest on a bottle containing harmful chemicals.

Certification can, however, be a quick and efficient way of deciphering the environmental quality of a product, as long as it is in fact an accredited certification that assesses good resource management, from manufacturing to use, including the processes that the companies themselves implement.

The PCS distinguishes between the various certifications that can be applied in Portugal and that are duly accredited by credible certification systems.

Greenwashing is when an entity or organization spends time and money on marketing actions to link it to good environmental practices instead of actually carrying out business practices that minimize negative environmental impacts. We could say that this is whitewashing the facts, but with a green brush. That’s why it’s called greenwashing.


  • The most classic example might be the company that sells fossil energy but advertises in its campaigns that it is working on and developing research into renewable energy, although it never stops using the energy that causes the greatest negative environmental impacts;
  • Or a hotel chain that claims to be green because it doesn’t change the towels in the rooms every day, but actually does very little in the back office to save water or energy;
  • Or a bank that consumes an inordinate amount of energy in its service buildings but at one point announces that it is going to plant trees in partnership with an NGO to help reduce CO2 emissions, when in fact there is no control over the green initiative;
  • Or even a company that stands by its good environmental practices, using recycled materials and providing environmental information about the product it sells, but which sets up its factory or megastore in a Natura Network or Ecological Reserve.

And many others…

It depends on the orientation of the windows:

The existence of sun screens – fixed or movable devices, to the SOUTH, should always be placed on the outside of the glass. In this way, the incidence of the sun on the glass is controlled, avoiding situations of overheating. The same is true in the EAST and WEST directions, but here, if possible, the external blinds should be made up of vertical blinds, as they allow better control of the sun’s incidence, which is always lower in these directions.

On the NORTH side, which should be used for corridors, built-in closets or bathrooms, openings should be kept to a minimum. Here it is important that the glass has an interior protection, precisely because, in the cold season, this is the only way to prevent the loss of energy (heat) through the glass.