A Passive House is a dwelling in which a year-round comfortable interior climate and good indoor environmental conditions can be maintained without the use of significant active space heating or cooling systems.
The concept of a Passive House is based on minimising heat losses and maximising heat gains, typically this includes optimising insulation levels with minimal thermal bridges, high thermal performance windows, very low air-leakage through the building, utilisation of passive solar, internal gains and good indoor air quality maintained by a mechanical ventilation system with highly efficient heat recovery.
By creating a thermally efficient building envelope and making optimum use of free heat gains the space heating requirements of a Passive House are minimised, thus reducing but not eliminating the need for a conventional heating system; the air supply system essentially serves to distribute the remaining heat requirement.
The creation of a Thermal Building Envelope with very low air-leakage (air-tight) and the provision of a mechanical ventilation system (HRV) is key to ensuring the required volume of fresh air needed for healthy living conditions is provided.
As a Passive House is more demanding than a conventional Irish house in regard to conception, for Passive Certified Houses design and execution of construction work, a quality approval process for checking and verification purposes must be maintained for performance and certification.
Passive Standard or Near Passive Homes are built to the same levels of performance and efficiencies, using the same demanding specification, giving you all the efficiencies without the final certification.
The main certification criteria, applicable to residential Passive House buildings, are described as follows:
Specific Space Heat Demand max. 15 kWh/(m2a)
Pressurization Test Result n50 max. 0,6 h-1
Entire Specific Primary Energy Demand max. 120 kWh/(m2a) incl. domestic electricity.
Useful cooling Demand (if applicable) max. 15 kWh/(m2a)
The above criteria for the Passive House is non-exhaustive and are explained further in detail, for Passive Certified Houses these must be verified in the Passive House Planning Package (PHPP), by Passive House Institute, Germany.