Most of the time, when we think of comfort in the home, we immediately associate this idea in our minds with a soft sofa, large and comfortable beds, spacious rooms, a well-equipped kitchen, etc. However, within this comfort, we almost never think of an element that goes unnoticed, but which is essential to achieve the desired well-being at home: the windows. And now, more than ever with rising energy prices, having windows that keep the heat in your house is very important. It's time to think about energy efficient windows in Spain and find out how you could save up to 30% on your energy bills as a result, with the help of Sandra Barañano, technical director of Cuida Tu Casa.
Heat loss through windows in Spain
Windows consume 13% of the energy in single-family homes in Spain, that is to say, 13% of the heat in our home escapes through them. A percentage that can reach up to 23% in the case of blocks of flats, according to OnVentanas. Precisely, the construction elements that separate the home from the outside are one of the weakest points in achieving thermal comfort at home, and windows are one of the weakest links, as they must not only provide thermal insulation, but also acoustic insulation (they protect from noise) and provide light, ventilation and security.
For this reason, it is essential that our windows have a series of characteristics to fulfil the function for which they were designed. Now, with winter knocking at the door, it is a good time to think about getting new windows so that when winter arrives, your Spanish home is well protected and doesn't waste energy. Because no matter how much you turn up the heating, if the windows are poorly insulated, it will be useless.
A guide to energy efficient windows in Spain
First of all, we must be clear that the quality of the windows is directly proportional to the materials they are made of. That is to say, the quality of manufacture of the joints, the material of the frame, the fittings, the glass or the shutter assembly will define the performance of the window. However, it must be taken into account that the necessary characteristics of each window will depend on its location, as depending on the location, it will be necessary to choose one or the other.
Building orientation
For example, in the case of glass, which in Spain generally occupies between 60% and 65% of the total surface area of a window, it has a decisive influence on the comfort in our home. However, few people know that depending on the orientation of the window, the glass must be of one type or another:
- North facing: North-facing facades are practically not exposed to solar radiation, only in the early morning hours. Therefore, not much sun enters through the windows, so it is advisable that the glass is large, i.e., that the glass is more important than the frame in the window so that it lets in as much light as possible without excessive heat loss. It is also important that the glass is low emissivity, i.e. that it has the capacity to reduce heat loss by reflecting the energy radiated by heating appliances. In this way, these glasses act as a shelter that keeps the heat from the heating in the rooms thanks to their 'rebound effect'. Moreover, in this case, as the glass faces north, it does not need solar protection.
- South facing: in this case, and contrary to what one might think, solar radiation is greater in winter than in summer, therefore, glass with the capacity to maintain heat (low emissivity) and a medium solar factor are also recommended to protect the house in summer and avoid overheating and to collect part of the free energy from the sun in winter. To reinforce this protection from the sun, it is recommended to install overhangs, awnings, blinds or curtains.
- East and west facing: in this case, solar radiation is direct, so it is advisable to equip the exterior windows with adequate solar protection that is capable of reducing the heating of interior spaces and glare. Therefore, the best option is to use glass that is also capable of reflecting energy and has a high solar factor, i.e. that does not allow the sun's energy to pass through.
The exception is for windows where there is solar protection independent of the window, such as awnings. In these cases the glass may have low solar protection, so that in winter it lets the sun's energy through.
Double glazing
There is also the option of double glazing, which is made up of two or more single panes of glass separated by one or more spacers. In fact, most windows in Spain, at least in newer properties, have double glazing. If these panes have also low-emissivity and reduce heat loss, they can generate energy savings of between 2% and 13%.
Preventing heat loss from windows
But when it comes to preventing heat loss, it is not only the glass that plays a role; the work of the window frame and its installation is also important. It should be clear that all types of carpentry require cleaning and greasing of fittings and, in the case of wooden carpentry, the protection of the finish (paints or varnishes) and biocide treatment (which prevents external agents from damaging the window) should be taken into account.
The frames are usually made of wood, metal or PVC, but there are usually cracks that allow air to pass through. This property is known as permeability and, as a result, air infiltration occurs, leading to heat and cold loss in winter and summer, respectively. However, wood and PVC are insulating materials, which is why there are no thermal bridges in joinery made of these materials if they are installed correctly and, as a result, no air leaks. On the other hand, metals, due to their high conductivity, are not insulating materials, which is why, to improve their performance, plastic parts and air chambers must be inserted, which is what is known as thermal break joinery.
Finally, in order to save energy and protect against noise, the frames of the joinery and the shutter boxes must be fixed in such a way as to guarantee air permeability and airtightness. With all these measures, energy savings can be between 5% and 30%.
Other ways to save energy and reduce household bills
Finally, there are other allies that reinforce this protection against solar radiation and energy leakage. These are the movable elements, which are well known to everyone, such as awnings, blinds and adjustable louvres. With regard to the former, it is advisable to carry out regular maintenance of the entire system, with special emphasis on the fabric, as it is the element that provides shade. In summer, it is advisable to unfold the awning before direct light begins to enter the house, while when it is windy it should be retracted so that it does not come loose. If it rains, wait until it dries before rolling it up to avoid damaging the fabric.
Blinds and shutters should be closed in summer during the sunny hours and raised at night, opening the windows of opposite facades at the same time, if possible, to cause cross ventilation and to renew the air in all the rooms of the house, thus achieving the appropriate air quality. It is important to take care of the winding belt or handle, avoiding abrupt operation or dropping them suddenly. In addition, during prolonged absences (such as holidays) we should not close them completely, as exposure to the sun produces a high concentration of heat that can damage the slats.
With all these recommendations, your window renovation should be a success and will make a difference to your electricity/gas bill this winter.