What are passive houses and how do they work?

Passive houses are one of the greatest architectural examples of bioclimatic and sustainable housing.

At Withfor, an ethical real estate agency based in Barcelona, one of our greatest commitments is sustainability, so we are going to tell you all about the construction of passive houses and what advantages they offer you and the environment.

What are they?

Traditional constructions seek to meet all comfort needs. However, it is not always possible to meet air conditioning needs for various reasons, and this is a problem that is now being tackled in homes for sale in Barcelona.

The lack of proper weatherproofing in the home means that when it is very cold, people will logically look to turn on the heating to be more comfortable. The same happens when it is hot: people will look for a cooling system.

In Passivhaus houses this does not happen because they are a special type of construction whose function is to reduce energy consumption by up to 80-90%, as they use a different design to the traditional one: the Passivhaus standard or norm.

This construction standard guarantees optimal conditions of comfort and indoor climate in the home, without the need to use conventional energy systems (heating, air conditioning, etc.), saving 15 kWh/sqm per year.

The Passivehaus concept

Wolfgang Feist was the founder of the Passivhaus Institute in the 1980s, and creator of the world’s first passive house in Darmstadt, Germany.

They are called “passive” because they are a very low-maintenance type of building. Thanks to the precision of their composition, they do not require much energy to weatherproof.

Types of biopassive houses

The difference between a traditionally built house and a passive house is not in the materials, but in the design.

The success of passive house design is that it makes the best possible use of the site’s conditions and makes the best possible use of the building materials.

This process optimisation is achieved by means of modular construction for maximum energy efficiency.

There are currently several companies in Spain that have developed architectural projects that follow the Passivhaus standard and have created a catalogue of passive houses.

The construction catalogue includes prefabricated passive houses based on the use of concrete and wood (most of them using PEFC or FSC certified wood). There are also many modular timber construction projects, or single-storey passive houses. Most of these constructions are smart and sustainable dwellings that include home automation systems for energy efficiency.

Characteristics of the Passivhaus standard

In order to obtain the Passive House building standard, some aspects are taken into account, which are evaluated by an official Passive Institute certifier.

• Thermal insulation

The facades are designed with large openings facing the sun during winter to capture heat, while materials such as pergolas are added to protect from solar incidence in summer. The façades are then properly insulated with low transmittance thermal insulation to prevent energy leakage during winter and summer.

• Thermal bridges

The design of passive houses seeks to avoid thermal bridges, which are the points of heat leakage (in winter). These are detected and repaired to optimise energy efficiency.

• Airtightness

Through the design and the correct use of the building materials used, the aim is to provide a high level of airtightness for walls, doors and windows. This prevents the loss of heat or cold during the seasons of the year.

• Quality doors and windows

Various resources are implemented such as: triple insulated windows with double glazing and air chambers. As for the carpentry, it should also be in a condition to be able to insulate properly.

• Ventilation system

Passive houses have a 24/7 mechanical and continuous ventilation system. This system allows high-performance heat recovery. In this way, energy is recovered from the house itself and there is no need for traditional air-conditioning in the house.

Advantages of these construction models

• Up to 90% energy savings.
• Solving the problem of air-conditioning in the home.
• Improve the quality of life.
• Promote sustainable housing and the saving of biological resources.
• Acoustic insulation.
• Improve the cleanliness of the home by reducing dust, pollen and mite production.
• Savings and economic profitability.

Prices of biopassive houses in Spain

According to various specialists, the construction of passive houses in Spain would represent an estimated cost overrun of between 5% and 15% over a traditional house.

The variation in price per square metre will depend on the construction model and the type of material used. And, of course, other conditions such as location, size of the building, etc. also play a role.

At Withfor, we are committed to sustainability, and we want our customers to be informed about ways to optimise energy resources in their homes to take care of our environment. We invite you to our Withfor House. We are here for whatever you need.