Learn all about the "passivhaus"

The efficiency and comfort revolution

Did you know that there are buildings and homes that require 75% less heating and cooling due simply to their construction design?

These are the passivhaus or 'passive houses', which use mechanical ventilation systems to recover heat, perfect thermal insulation, correct orientation, and eliminate heat or cooling leaks, among other standards that must be met to earn the Passivhaus certification.

Passive houses not only favor lower energy consumption, with the economic savings and lower carbon footprint that this implies, but also, according to various studies, are healthier for those who inhabit them. Thanks to the renewal of air, the more sustainable materials used, and the search for natural light, they help prevent diseases. We explain the characteristics of passivhaus houses and the advantages that have made them popular in recent years.

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What is a "passivhaus" or a passive house?

The defining characteristic of passivhaus houses is their maximum energy efficiency and minimum energy requirement for heating and cooling. This construction system employs bioclimatic architecture techniques so that these homes generate a comfortable temperature practically on their own at any time of the year.

Passive houses have recently become a trend in the field of construction, due to their efficiency and commitment to sustainability. The concept was coined in 1988 by professors Bo Adamson, of Lund University in Sweden, and Wolfgang Feist, of the Institute for Building and Environment in Germany, which resulted in standards that the Passivhaus Institut checks in order to issue passivhaus certification.

These characteristics, which make them passivhaus, make it possible to reduce energy consumption in these homes by around 75% compared to homes built using conventional construction techniques.

Characteristics of passive houses

The Institut für Baubiologie und Okologie (Institute for Building Biology and Ecology) in Bavaria - in charge of all aspects related to bioconstruction - establishes a total of 25 guidelines for bioconstruction that serve as indicators and define the basic characteristics of this discipline, which, broadly speaking, can be summarized as follows:

Correct orientation. The proper orientation of the house is another of the requirements to be able to use the term passive house. This construction model takes into account the climate of the area and the bioclimatic resources that can be used in it, and solar energy is a fundamental point to ensure energy efficiency.

Highly effective thermal insulation. Passive houses use a perfect insulation in exterior and interior walls, floors, and ceilings so that there is no loss or gain of temperature. For this purpose, materials with a very high thermal conductivity and the appropriate thickness are used, which are also chosen according to the climate of the place where it is located. Cork or wood fiber are two of these highly insulating and biodegradable materials.

Windows and doors with high insulation capacity. Along with the envelope, doors and windows are the other points through which a house can lose heat or cold. Those used in a passivhaus house have low thermal transmittance, double or triple glazing, and even the carpentry uses techniques that allow high insulation, so that no temperature losses or gains occur at these points.

There are no thermal bridges. A thermal bridge is that point in which, either because it joins several construction elements, or because of the characteristics of its materials, it favors the loss of thermal energy. Passive houses eliminate any thermal bridge in the envelope, which also avoids any condensation problems.

Air tightness of the envelope. In addition to having a high insulating capacity, the envelope of the passivhaus houses guarantees air tightness. This not only facilitates the ventilation of the house, but also improves the insulation itself, preventing moisture or drafts.

Mechanical ventilation system. Passive houses have mechanical ventilation systems that renew the air in the rooms and extract humidity, odors, and gases harmful to health such as CO₂; in addition to maintaining the optimum temperature throughout the year. Its function is to improve both energy efficiency and hygienic efficiency.

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Benefits of the passivhaus

For all these reasons, passive houses have a series of advantages that conventional houses do not have:

Greater energy efficiency and less consumption. The houses that have a passivhaus certification enjoy greater energy efficiency, since it is one of the objectives with which they are designed. The lower demand for artificial heating and cooling translates into lower energy consumption and therefore also into economic savings.
Lower carbon footprint. This type of housing contributes to the reduction of emissions by using bioclimatic architecture techniques and requiring less energy consumption.
Healthier. Better ventilation, more natural light, harmless materials... Passive houses have certain characteristics that also make them healthier homes.
Greater comfort. The optimum temperature maintained by passivhaus-certified houses, better acoustic insulation, and optimum orientation, among other factors, make them more comfortable homes.

Repsol and energy efficiency

If along with the above standards we add the use of renewable energies to the passive house, we further reduce the carbon footprint. In this sense, the installation of photovoltaic panels is an alternative that fits this type of design. Solar panels allow us to make use of renewable energies at home, thus contributing to the reduction of emissions and saving on consumption and electricity bills.

At Repsol, we promote the use of renewable energies, as part of our commitment to be the first multi-energy company to achieve net zero emissions by 2050. We also make it easier to control consumption in the home, for example, thanks to Vivit, the app that allows you to control the energy expenditure of each appliance, your bills, or save by accumulating surplus solar energy, among other advantages.