This article was written by Carlos Hernández Puente, industrial engineer and vice president of the Association of Executives and Directors EJE&CON.
Passive houses, also known as "Passivhaus", represent a construction model that integrates energy efficiency, comfort and sustainability. While it may seem like a futuristic concept, this type of construction is already gaining traction in Spain. But what does it actually mean to live in a passive house, and what benefits does it offer?
Energy savings of a passive house
A passive house is characterised by a significant reduction in energy consumption. To put this into perspective, traditional homes with energy ratings of E or F, commonly found in buildings constructed before 2007, consume over 200 kWh/m² per year. This results in energy bills of approximately €2,000 annually for an average 100 m² home.
In contrast, a passive house reduces this consumption to between 15 and 30 kWh/m² per year. In other words, the annual energy costs are reduced to just €150-300, representing savings of up to 90%.
What is Passivhaus construction?
The low energy consumption of a passive house is achieved through the application of five key principles:
- Quality thermal insulation: Efficient materials that keep the interior temperature stable.
- Air tightness: Prevents heat or cold leaks.
- High-performance windows: Triple glazing and insulating materials.
- Mechanical ventilation with heat recovery: Ensures clean air without losing heat.
- Absence of thermal bridges: The design eliminates areas where energy is lost.
This efficient design not only lowers energy costs but also greatly enhances indoor air quality.
Health, comfort and well-being
One of the greatest advantages of passive houses is the improvement in the health of their occupants. The heat recovery ventilation system ensures a constant flow of fresh air, removing pollutants, humidity and dust mites. This is particularly beneficial for individuals with respiratory issues.
Additionally, airtightness and insulation help to reduce external noise, creating a quieter and more peaceful environment. They also maintain a stable and comfortable temperature year-round, without draughts or sudden fluctuations in temperature.
Passive houses and solar energy: a perfect combination
When the efficiency of a passive house is combined with solar panel installation, the environmental impact becomes positive. A Passivhaus already has very low energy consumption, so a small solar system can meet all its energy needs. In fact, in many cases, the generation of photovoltaic energy transforms the house into a net-positive home, meaning it produces more energy than it consumes.
What about old houses?
The Passivhaus standard is not exclusive to new builds. There are already numerous examples of homes over 20 years old that have undergone energy rehabilitation following the same principles:
- Improving insulation in façades, roofs and floors.
- Replacing windows with high-efficiency models.
- Installing ventilation systems with heat recovery.
Studies, such as the one on the housing stock in Navarra, show that these interventions can reduce energy consumption by up to 80%, offering clear benefits both economically and in terms of comfort.
A long-term investment
Although constructing or refurbishing a home to the Passivhaus standard may incur an additional cost of 5-10%, there are subsidies available that can cover up to 80% of the total project cost, allowing for a quick return on investment through the energy savings achieved.
It is also important to consider that the market value of a home typically increases by around 20% following a comprehensive renovation, and this increase can be even higher depending on various factors.
Conclusion: efficiency, health and future
Passive houses are an example of how architecture can seamlessly combine energy efficiency, economic savings and well-being. It's not just about reducing bills; it's about living in a healthier, more comfortable environment.
When renewable energies, such as solar power, are integrated, the benefits extend beyond financial savings to positively impact the planet. Passive housing is not a trend; it is a step towards a more sustainable future for all.
