The passive house is comfortable, energy efficient and has a reduced impact on the environment. If you wish to build your passive building in Portugal you may be wondering what is the cost of a passive house.
Additional costs of a passive house
There are specific additional costs related to passive houses compared to low-energy and standard houses. These additional costs come in particular from:
- Ventilation
- Insulation
- Airtightness
A gap that tends to decrease
The first economic studies carried out showed that passive houses had an extra cost of 16% compared to standard constructions. But since then, things have changed. Especially thanks to the more efficient windows. It is now possible to reduce the thickness of the insulation and therefore reduce this price difference.
A study conducted by the Passive House Institute (PHI) shows that the additional investment for a passive house would now be less than 5% of total construction costs (study conducted in Germany).
However, it is necessary to study each case on a case-by-case basis. The insulation needs in Portugal will be different from those in Germany.
A passive house in Portugal will not necessarily be more expensive to build than a new construction that must comply with current Portuguese regulations. In the Decree 379-A/2015, the values of the heat transfer coefficients are close to those recommended for passive construction in Portugal.
In a passive house, heating needs are 4 to 10 times lower than those in a standard house. The electricity bill will therefore be lower. In addition, as electricity prices will tend to increase, passive house tenants will no longer have to worry about this increase.
PHI points out that even after 30 years, energy costs can continue to be reduced because the inactive components of the passive house continue to operate as long as the house is in place.
How to reduce additional costs of a passive house ?
Passive houses can be a bit more expensive than traditional construction but several techniques can allow cost optimisation. In order to optimize the cost-benefit ratio, it is necessary to:
- Favor compact shapes: a compact building will be more energy efficient
- Define a good orientation of the windows: it will increase solar gains in winter
- Ensure airtightness
- Define a natural ventilation to cool the room (except during the hottest hours)
- Increase the insulation of the roof and slab
- Limit the thickness of wall insulation (make sure to comply with the Passivhaus standard)
- Limit the length of ventilation pipes to limit heat losses
- Avoid thermal bridges
Building a passive house is a long-term sustainable investment. Indeed, compared to a conventional construction, resources and energy are saved.