What is a Passivhaus?

We interviewed architect Jerome Wepierre and surveyor Enrique Salavert, from the Jessica Bataille Company team to decipher the keys to a passive house, which is no longer just a constructive trend but a necessity on the road to sustainability.

Why is a Passivhaus more sustainable?

‘The goal of passive homes is to achieve between 70% and 90% energy savings compared to a conventional home. The important thing is, on the one hand, to guarantee the watertightness of the building, completely eliminating air infiltrations and, on the other, to reduce energy consumption to a minimum. In this way, we reduce environmental impact while respecting the environment. In addition, this increases the comfort and well being of the people who live inside it. Creating a Passivhaus house doesn’t just save on bills, it also means living in a healthy space,’ explains Jerome.

Which Jessica Bataille Living houses could be considered Passivhaus?

‘The first house that can be considered PassivHaus will be Ca La Siesta: it is a project in which we are studying all the data from the outset so that it meets all the criteria of the regulations. And we have a project that is very close to Passivhaus standards which is La Pinada, since it meets 70% the criteria but is not certfied. The priority in this case, is comfort and savings, which are very important, also all our future Bataille Living projects are going to be reformed following the Passive House standard’.

There are houses that are built under sustainability criteria but do not have the Passivhaus seal, what is the difference between them?

‘Sustainable construction must have special respect and commitment to the environment: it involves the efficient use of energy and water, resources and materials that are not harmful to the environment, it is healthier and is aimed at reducing environmental impacts. I think the first step is to work with existing houses adapting them to our lifestyle now, without having to demolish and start over. In the houses that we are renovating, we take great care with the issue of energy saving, comfort and that they are a healthy space. It is very important that a house that does not become a Passivhaus be renovated with criteria to guarantee the greatest tightness. By contrast, when we talk about Passivhaus we refer to those that have a certificate at European level that they have achieved by complying with a predetermined regulation’.

You have to comply with 5 basic rules, aimed at not consuming energy, as Enrique Salavert explains:

1.- Thermal insulation of all walls: hence the importance of installing, for example, good windows with double glazing.

2.- Avoid thermal bridges, which are those uninsulated holes. The meeting of a window with the wall, for example.

3.- Install mechanical ventilation systems with heat recovery.

4.- Sun protection. It is overlooked in our area: we see houses that for a purely design issue have very large windows. This is a greenhouse because a lot of radiation enters and you have to constantly refrigerate your home. There are houses in which you have to turn on the air conditioning in February… And that is not comfortable.

5.- Air tightness. One of the energy losses comes from unwanted drafts, especially in cold climates, in the joins of the windows due to aluminum sliding windows or holes in doors. That is why we have to try to make the house completely hermetic.

‘And an important criteria can  be the orientation of the house to make the most of the climatic conditions and protect it from both cold and heat’, reflects Jerome.

And the future? ‘At a constructive level, we must take those steps towards sustainability, as well as work with local materials as far as possible, because the Passivhaus concept is here to stay’, Enrique concludes.