The thermal requirements for the Isover Multi-Comfort House are based on the Passive House design principles. These design principles incorporate excellent thermal insulation of the building envelope (including windows and doors), airtight constructions, and ventilation systems with heat recovery for a permanent supply of fresh air. Small additional heating or cooling systems may also be integrated if needed depending on the climate zone.
Compared to conventionally built houses, the heating or cooling energy demands of a passive house are lower by about 75 %. And in contrast to old buildings, savings amount to as much as 90%.
Passive House buildings provide a high level of occupant comfort while using very little energy for heating and cooling. They are built with meticulous attention to detail and rigorous design and construction according to principles developed by the Passivhaus Institute in Germany, and can be certified through an exacting quality assurance process.
The Passive House Standard
ThePassive House Standard requires:
- a maximum space heating and cooling demand of less than 15 kWh/m2.year or a maximum heating and cooling load of 10W/m2.
- a maximum total primary energy demand of 120 kWh/m2/year.
- an air change rate of no more than 0.6 air changes per hour @ 50 Pa.
To achieve the Passive House Standard in the UK typically involves:
- very high levels of insulation
- extremely high performance windows with insulated frames
- airtight building fabric
- 'thermal bridge free' construction
- a mechanical ventilation system with highly efficient heat recovery
The Passive House Institute has developed a series of certification processes to ensure the quality of any official Passive House buildings and practitioners:
- The Passive House Planning Package (PHPP), used to inform the design process and to assess or verify compliance with the Passive Houses Standard.
- Certification for designers who have the expertise to deliver Passive House buildings.
- A certification process for Passivhaus buildings, which applies both to the proposed design and the completed building.
"The heat losses of the building are reduced so much that it hardly needs any heating at all. Passive heat sources like the sun, human occupants, household appliances and the heat from the extract air cover a large part of the heating demand. The remaining heat can be provided by the supply air if the maximum heating load is less than 10W per square metre of living space. If such supply-air heating suffices as the only heat source, we call the building a Passive House."
Univ. Prof. Dr Wolfgang Feist
Head of Energy Efficient Construction/ Building Physics at the University of Innsbruck, Austria and Director of the Passive House Institute, Darmstadt, Germany