Thursday, April 16, 2020

What are Passive Houses? Are they the future of construction?

Passive House is called when a building or dwelling has almost zero energy consumption, where the natural resources of its surroundings are used efficiently, without the need for external energy and maintaining high levels of quality and climatic comfort inside the dwelling.

In the initial phase of the project, the characteristics of the place where the house will be built should be studied, with the intention of adapting its design and choosing the most appropriate construction materials to enhance environmental conditions: solar radiation, orientation, volume, ventilation , humidity, etc. 

In recent years the number of Passive house (German name that defines this type of house) has been multiplied by a greater awareness of environmental respect, energy saving and the forthcoming entry into force of the European Directive 2010/21 / EU , by which, as of December 31, 2020, all new private residential constructions or renovations must have the regulations of Nearly Zero Consumption Buildings (E CCN). 

Elements of the construction of the Passive Houses.

The Passives house Consortium, Spanish promoters of the standard, sets out the basic principles that define a Passive House: 

1º.- THERMAL INSULATION: the most suitable covering materials are used that insulate from the heat and cold outside. A passive house means 2-3 times more insulation material and better quality for its construction than those used in a traditional home. 

2º.- TIGHTNESS: the aim is to avoid the entry of uncontrolled air leaks from outside to inside the house. These houses, thanks to their tightness and insulation, keep the interior of the house between 20-25 degrees most of the days of the year. 

3º.- ABSENCE OF THERMAL BRIDGES: both in windows, walls, ceilings and foundations that can produce loss of cold or heat in the home. 

4º.- MECHANICAL VENTILATION WITH AIR CIRCULATION: which allows a recirculate of the indoor air, guaranteeing the highest quality of air that is continuously filtered and renewed, an especially important aspect for people who suffer from allergies or asthma. Ventilation in bathrooms and kitchen is taken outside directly to avoid bad odors, but not before taking advantage of its temperature to save energy. 

5º.- HIGH PERFORMANCE WINDOWS: where triple glazing, high-efficiency profiles and carpentry are used that allow maximum tightness. Windows must be properly oriented to ensure that sunlight is hot in winter, taking advantage of that energy and where the entry of light and heat in summer can be controlled. 

6º.- EFFICIENT SUPPLIES: both sanitary hot water (DHW) and energy consumption are made taking into account the most efficient available renewable energy systems according to the project. 

How much does a Passive House cost compared to traditional construction? 

Taking into account both the design and the construction of a Passive House with respect to traditional construction, this represents an increase in construction costs of between 5-10%. 

The current average construction price is around € 750-1050 / m² depending on qualities, taxes, fees and professional fees not included. In other words, we would be talking about the m² of a Passive House being between € 900-.1,100 / m² built. Making it clear that any calculation has to be done with each particular case and will depend on the size of the projected house and the final qualities. 

A good strategy is to have several budgets for the different items to get the best value for money. 

Interested in investing in a Passive House? 

From an economic point of view, the main advantage that will make this type of construction the future is the energy savings achieved, which can even reach 90% of the energy supply bills of a traditional home. 

Thinking about the long term, the increase in construction cost is offset by energy savings, it is also estimated that the sale price of a Passive House is revalued by more than 20% compared to what it is not