What is Passive House?

“Passive House is a building standard that is truly energy efficient, comfortable and affordable at the same time. Passive House is not a brand name, but a tried and true construction concept that can be applied by anyone, anywhere.” – Passivhaus Institut

The aim of “Passivhaus” is to create a thermally competent envelope which uses free heat gains to minimize the space heating requirement. Passive house is the ultimate building for energy efficiency. Passive House designs are globally renowned for being the leaders in terms of energy performance. Passive House buildings are widely considered as being able to provide extreme comfort in a healthy interior climate. This is sustained without using heating or cooling systems.

Passive house construction presents one of the most economical methods of providing comfortable living and working environments. The “Passivhaus Institut”, Germany were rigorous in developing the Passive House Construction Standard. Passive House Builders are required to be strict in following these demanding specifications. Passive house designs must consist of outstanding levels of insulation with minimal levels of thermal bridging. Passive homes are required to have very little air leakage throughout, solar gain is utilized and mechanical ventilation is provided with competent heat recovery.

Important features in Passive House Designs

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The most important feature of a Passive house is insulation. Without heavy insulation it is impossible to meet passive house standards. It is also vital that during the Passive house construction period that there are no gaps left in the insulation. It must be continuous throughout the house as it prevents air getting in or out. In Passive House designs, the insulation is usually found in the walls, floors and roof of a dwelling.


Due to the extensive use of insulation in Passive Homes air cannot travel through the walls. In order to keep a very healthy indoor environment, Passive House builders install a ventilation system. A Passive house needs to be extremely well ventilated in order to control the airflow in and out of the house. In this way it is protected. It is also a regulator for the temperature within the Passive Home. As the air is coming in it is heated by the air going out.

Solar Gains

Passive House designs also insure that the house is heated by Passive solar gains. This means the windows in Passive homes warm the building using heat from the sun. Windows are a vital part of passive house construction in order to meet passive house standards. This is because windows can be critical in carrying on the continuous flow of insulation throughout a Passive home. It is of the utmost importance that Passive House builders install competent windows correctly.

Air Tightness

You need to achieve a maximum of 0.6 air changes per hour at 50 Pascals pressure. Airtigntness is key in maintaining a consistent and comfortable indoor environment.

The Thermohouse Solution for Passive House Construction

The Thermohouse wall, roof and ground floor insulated board achieve the requirements set by Passive House Standards.

Components Passivhaus Standard Thermohouse System
Insulating Concrete Formwork (ICF) Walls U = 0.15 U = 0.12 / 0.10
Roof U = 0.15 U = 0.15
Underfloor Board U = 0.15 U = 0.12
Airtightness ≤0.6 ac/h ≤0.6 ac/h
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