What is a passive house?
Established by the Passivhaus Institute in Darmstadt, Germany in 1996, “passive house” was one of the pioneering concepts for building low-energy houses and today is a leading building standard. The design is focused on making best use of the “passive” influences in a building – like sunshine, shading and ventilation – rather than active heating and cooling systems such as air conditioning and central heating. Coupled with very high levels of insulation and airtightness, this makes it possible for a passive house to use 90 percent less energy1 than a typical dwelling.
What defines a passive house?
A building must meet several criteria to achieve the passive house standard:
Space heating: The energy demand for space heating must not exceed 15 kWh/m2 of living space per year or 10W/m2 at peak demand. This contrasts with the 100W/m2 needed in a typical house.
Primary energy: Total energy needed for all domestic applications (heating, hot water and domestic electricity) must not exceed 60 kWh/m2 of living space per year.
Airtightness: Passive buildings are very airtight and should have no more than 0.6 air changes per hour at 50 pascals of pressure.
Thermal comfort: Living areas should be comfortable all year round, with no more than 10 percent of the hours in a given year exceeding 25°C.
Intelligent passive design
To achieve this level of performance, builders use intelligent passive design – for example ensuring the house is oriented and designed to make best use of sun and shade – together with the five passive house principles (see factbox).
Very high levels of insulation are a key element of passive construction, which keeps heat losses so low that a house can be kept warm either without heating or just by preheating the fresh air entering rooms. Passive buildings feature a continuous insulating envelope like a warm coat around the building, and an airtight layer.
ROCKWOOL’s non-combustible stone wool insulation is ideal for reaching passive house standards because it fits easily into the building and stays in shape over time, lets vapour pass through, is long-lasting and fire-safe.
This is why we have created a unique wall system combining stone wool columns, ROCKWOOL insulation and airtight OSB4 boards on the inside. Rockzero is a highly energy efficient wall system that also offers fire protection and superior indoor comfort. You can read more about Rockzero here!
1 "25 Years Passive House – Interview with Dr. Wolfgang Feist", Passive House Institute