Windows in our homes, in addition to the visual aspect, perform specific, necessary for the proper functioning of the properties. First of all They ensure safety, secondly, they increase the comfort of the household members, and thirdly – well-chosen windows allow you to reduce the cost of heating the house. The latter element is particularly important in the case of windows in a passive house, which are characterized by low heat transfer coefficient. In this post we will discuss passive windows and windows for energy-efficient houses.
What is a passive house and what is an energy-efficient house?
A passive house is a type of home that has been specifically designed to be energy efficient. It is very important to understand what a passive house is before you decide if it is the right choice for you and your family. It is both an architectural style and an energy efficiency standard. Buildings that meet the passive house standard are extremely energy efficient, using up to 90% less energy than traditional buildings. Such a building must have dedicated windows for a passive house. Only then will it correctly meet its properties and guarantee a low level of energy consumption.
Energy-efficient houses, on the other hand, are buildings with lower heat demand compared to traditional buildings. The annual heat demand is from 70 kWh/(m2· K). Current standards set a limit of 160 kWh/(m2· K). Thanks to its design, selection of appropriate materials and increased insulation, energy-efficient buildings have an increased energy standard. Each element of the building has an impact on whether the heat will escape. Such elements include m.in. exterior walls, floors, roofs. In an energy-efficient house These elements are precisely insulated, e.g. with polystyrene.
What to consider when choosing windows?
When building or renovating a passive house, one of the most important decisions to make is the choice of window type. Many factors must be taken into account when making this decision, from thermal properties to aesthetics. Below are the following: A few rules that will be useful when choosing both windows for a passive house and for an energy-efficient house.
- The side on which the window is located is important – the largest window surface, additionally with a high transmittance coefficient, should be on the south side, while on the north side There should be definitely fewer such windows. And windows located on the east or west side do not bring any energy benefits.
- Where windows come into contact with the building structure, multiple layers of insulation are required for the windows to meet their properties.
- The method of installing windows has a big impact on the heat transfer coefficient U, and its incorrect execution may disturb the heat balance of the entire building.
- When designing a house, it is best not to place wide eaves and canopies above the windows, as they can disrupt your home’s heat management. It is best to install blinds or awnings, which can be adjusted if necessary.
- An important aspect to take into account is also whether there are trees or other elements around the space on which our house will be located that can darken the windows. For the greatest benefit, Lush vegetation around the house should be avoided.
Which windows to choose?
The heat transfer coefficient U for passive windows must not exceed 0.8 W/(m2· K), as in the case of exterior doors and garage doors. To protect the house from heat loss in winter and heating in summer, it is necessary to equip large windows with covers, such as blinds or awnings. It is worth noting that external window protection can Reduce heating costs by up to 30%. In passive houses there is also the possibility of mounting aluminum windows, however, they must be made in energy-saving technology.
In the case of energy-efficient apartments, the heat transfer coefficient of windows and external doors should not exceed 1.3 W / (m2K). If the building design provides for large windows, heat loss can be reduced by installing special windows with a U-value lower than one of the standards, i.e. less than 0.8 W/(m2· K), including those with a glass of three panes and frames made of multi-chamber profiles with thermal insulation inserts.