The Passivhaus standard adapted to the Mediterranean climate

One of the main features of the Passivhaus standard is that it can (and should) be adapted to different climate zones to achieve energy efficiency and thermal comfort wherever you are.

Although the Passivhaus standard was born in Germany, which is characterised by an inclement winter, this construction method has spread all over the world. In 120 countries there are already Passivhaus buildings adapting to all types of climate, and Spain is no exception.

So read on and find out more about how the Passivhaus standard is adapted to our Mediterranean climate!

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Characteristics of the Passivhaus standard

Passivhaus is an energy efficiency standard that is used in the design of homes and buildings to reduce their ecological footprint. This results in ultra-efficient homes that require very little energy to heat or cool their spaces and feel comfortable.

In general terms, these are the requirements that a building must meet in order to be certified as Passivhaus:

• Heating demand less than 15 kWh/m² per year.
• Cooling demand less than 15 kWh/m² per year.
• Primary energy demand less than 60 kWh/m² per year.
• Airtightness less than 0.6 air changes per hour

I recommend you to read this article of our blog if you want to know in more depth what the Passivhaus standard is and how it was born.

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What is the Mediterranean climate?

The Mediterranean climate is a temperate type of climate characterised by hot, dry summers and cold, rainy winters. In autumn and spring, both temperatures and rainfall are highly variable.

Although it is so called because it is the characteristic climate of the entire Mediterranean Sea basin, this type of climate is present in other parts of the world, such as the coast of California (United States), the central coast of Chile, southern Africa and south-western Australia.

As you may have already guessed, this is the type of climate in the Barcelona area, where we mainly focus the construction of our houses.

Adapting the Passivhaus standard to the Mediterranean climate

What is important when adapting the Passivhaus standard to the Mediterranean climate is how to achieve a comfortable indoor temperature in both winter and summer with minimum energy consumption.

For this, the specifications of the Passivhaus standard are combined with bioclimatic strategies to take advantage of the surrounding conditions. Here is a brief overview of the factors to be taken into account:

From the Passivhaus standard:

• Windows: For this type of climate it is advisable to use high performance windows with double glazing (triple glazing is not necessary) and low emissivity glass, in order to reflect the heat inside the house in winter and keep it outside during the summer.
• On the ventilation system: Including a mechanical ventilation system with heat recovery helps to regulate the temperature in both winter and summer, as it equalises the temperature of the outside air with the inside air before it is brought into the house.
• On insulation: According to the Passive-on study, the optimum thickness for the Barcelona area is 15 cm for vertical envelopes, 10 cm for the roof and 1 cm for the sill. In addition, it is advisable to insulate the outer layers of the façade; in this way, the façade materials heat up at a slower rate.

Bioclimatic strategies:

• On orientation: South-facing openings allow solar radiation to penetrate the interior of the dwelling in winter. In summer, these same openings can take advantage of air currents to cool spaces, provided that the solar radiation is blocked with some kind of protection.
• On the distribution of rooms: Occasional use rooms should be placed in the north and more frequent use rooms in the south, where solar radiation is easier to control and exposure to cold winds is less.
• On solar shading: It is important to consider a solar shading system for openings. This can be a cantilever, canopy, awning or louvres, either horizontal or vertical. Well-planned vegetation can also be very useful as sun protection.
• On night-time cooling: During the summer, it is advisable to take advantage of the slightly cooler temperatures at night to ventilate the house. Therefore, it is during this time of the day that it is suggested to open the windows.

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So, one only has to look at the large number of houses built to the Passivhaus standard in Catalonia to realise that this standard can not only adapt to different types of climates, but that it does so marvellously. The key is to understand the environment where the house is going to be built and to use other bioclimatic strategies to enhance the results.

Are you thinking of building a passive house in the Barcelona area? Schedule a video call with us to discuss your project. 😁