Construction of passive house or passivhaus

Specifically, buildings constructed to passivhaus standards must meet a number of requirements. The first one is reducing heating and cooling needs by 75%, while the rest of the energy can easily be covered by renewable energy. Additionally, to obtain Passivhaus certification, buildings must meet these requirements:

• HEATING DEMAND < 15 kWh/(m²a)
• REFRIGERATION DEMAND < 15 kWh/(m²a)
• PRIMARY ENERGY DEMAND < 120 kWh/(m²a) (heating, hot water and electricity)
• TIGHNESS < 0.6 air changes per hour (value with a pressure differential of 50 Pa)

Through different techniques and applications, they minimize the use of conventional heating and cooling systems, taking advantage of the weather and sunlight conditions of each place. In other words, they are designed and built with a clear strategy: make the most of light and solar radiation, achieving high thermal insulation and a renewal of the air through a ventilation system. But how is this achieved? On what aspects is the design and construction of a passive house based to achieve the passivhaus standard?

• An study of the bioclimatic environment The passivhaus concept has to be adapted to the atmospheric conditions of the region in which the house will be built. To do this, passivhaus specialized architects take into account temperature, humidity levels, wind direction, site sunlight and shadows, among other issues. All these aspects can have advantages or disadvantages to achieve greater energy efficiency.
• An excellent thermal insulation. It is, without a doubt, the most important aspect when it comes to improving the energy efficiency of homes and, therefore, of passivhaus construction. Every building aims to protect us from the outside environment by creating an indoor climate that is generally supported by heating or cooling systems. Among the most effective measures to achieve a comfortable indoor climate without resorting to these systems is the thermal insulation of the building. The building envelope, formed by the exterior walls and the roof, must have a low thermal transmittance, something that is achieved with systems such as Sismo Building Technology.
• Absence of thermal bridges. Directly related to the previous point, there is the importance of reducing thermal bridges as much as possible. We are talking of areas such as door and window openings, where heat or cold are more easily transmitted. An issue that is easily achieved by incorporating our industrialized system into the project. Unlike others, Sismo is characterized by offering continuous insulation, which prevents the breakage of thermal bridges in practically all elements, such as boxes for blinds, jambs of windows, lintels or pillars.
• Quality of materials in doors and windows. Since they are the main points of energy leakage, double or even triple glass windows are used, accompanied by a PVC frame, the most suitable for its low thermal transmittance.
• Airtightness. It is about reducing the cracks and gaps that can cause leaks and drafts, so that the house is airtight enough. For this, it is necessary to especially take into account the planning of housing meetings to avoid this type of problem.
• Mechanical ventilation with heat recovery. Passive houses recover a large part of the energy generated inside, both by people and household appliances, renewing the air used to thermally condition the home.

In summary, the basis of an environmentally sustainable design is to give an appropriated response to the disadvantages and advantages of the local weather, and to apply a series of constructive measures that allow us to dispense with mechanical systems of thermal conditioning that consume energy, producing emissions of greenhouse gases.

The application of Sismo to any sustainable housing project helps considerably to achieve these objectives, while simplifying the process thanks to the simultaneity with which different phases are executed. For example, with Sismo the hermeticity and the insulation are completed at the same time. This saves time and money, especially in a passivhaus project, which has many steps that are usually carried out in different phases.