What is a Passive House?

09 dicembre 2007
What is a Passive House?

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A passive house is a building in which you can maintain a comfortable environment internal climatically throughout the year without resorting to active heating systems or air conditioning.

The house practically alone maintains the ideal temperature its own, hence the definition of "passive house". Obviously, definitions and specifications vary significantly depending on the place where a house is built passive, because it is clear that there are differences between a house built in Norway and one in Sicily.

The basic approach does not change, and the requirements for a passive house built in Europe were established in less than 15 kWh per square meter per year for heating only, with a consumption of less than 40 kWh per square meter to the year for what it regards the total energy consumption, including heating, hot water and regular consumption of lighting and electrical appliances.

It is therefore obvious that the low total power consumption of a house can be passive totally covered through the use of renewable energies, and that the combined power of a passive house is less than consumption only for hot water and normal use of electricity (without heating) of a home European average. The total consumption of a passive house is less than a quarter of the corresponding house built in traditional technologies.

But what are the costs necessary to achieve this ambitious goal?

A little higher than a traditional house. Indeed, a passive house should have a total cost (including construction, equipment and operating costs for 30 years) than those of an average new construction traditional.

To conclude this brief introduction to passive homes, here are the basic characteristics that should have a building to fall under this definition:

A compact form and a good thermal insulation: All components of the exterior of the house were isolated until it reaches max values. U 0.15 W / (m2K).

Orientation towards the south and considerations sull'ombreggiatura: Use passive solar energy is a key factor in homes passive.

Glass window frames and high efficiency: Windows (both for what concerns the structure that the glazing) should have a U-value not exceeding 0.80 W / (m2K), with a coefficient of solar gain around 50%.

Impermeability of the external structure: Loss of air through cracks and joints should be less than 0.6 times the total volume of the house per hour.

Pre passive fresh air: Fresh air can be introduced into the house through underground pipes carrying out an exchange of heat with the ground. This preriscalda the cold air from the outside to a temperature of at least 5 ° C in the cold winter days, when the air outside is well below zero.

Recovery of heat from leaving through an air-to-air heat exchanger: Much of the heat content in hot expelled from the house is transferred all''''aria fresh input, with a recovery of about 80% heat.

Production of hot water through renewable energy hot water is produced by solar panels or heat pumps.

Low-consumption appliances: The use of low-consumption appliances such as refrigerators, dishwashers, freezers, light bulbs, washing machines, dryers, etc. is essential in a passive house.

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