passive houses

Passive house certificate criteria:

For a building to be considered as a Passive House, it must meet he following criteria:

1st criteria:

The Space Heating Energy Demand is not exceed 15kWh per square meter of net living space (treated floor area) per year or 10 W per square meter peak demand.

In climates where active cooling is needed, the Space Cooling Energy Demand requirement roughly matches the heat demand requirements above, with a slight additional allowance for dehumidification.

2nd criteria:

The Primary Energy  Demand, the total energy to be used for all domestic applications (heating,hot water and domestic electricity) must not exceed 120 kWh per square meter of treated area per year.

3rd criteria:

In therms of Airtightness, a maximum of 0,6 air changes per hour at 50 Pascals pressure, as verified with onsite pressure test. (in both pressurized and depressurized states)

4th criteria:

Thermal comfort must be met for all living area during winter as well as in summer, with not more than 10 % of the hours in a given year over 25Celsius.

All of the above criteria are achieved through intelligent design and implementation of the 5 Passive House principles:

• thermal bridge free design
• superior windows
• ventilation with heath recovery
• quality insulation
• airtight construction

Thermal insulation:

All opaque building components of the exterior envelope of the house must be well-insulated. For most cool-temperature climates, this means a heat transfer coefficient (U-Value) maximum of 0.15 W/m²K . 

 Superior windows:

The window frames must be well insulated and fitted with low-e glezings filled with argon or krypton to prevent heat transfer. For most cool-temperature climates, this means a U-value of 0.80 W/m²K or less. (With g-values around 50%. -g-values= total solar transmittance, proportion to the solar energy available for the room)

Ventilation with heath recovery:

Efficient heat recovery is key, allowing for a good indoor air quality and saving energy. In Passive house, at least 75 % of the heat from the exhaust air is transferred to the fresh air again by means of a heat exchanger. 

Airtightness of the building:

Uncontrolled leakage trhough gaps must be smaller than 0,6 of the total house volume per hour during pressure test at 50 Pascal (both pressured and depressured) 

Absence of thermal bridges:

All edges, corners, connections and penetrations must be planned and executed with great care, so that thermal bridges can be avoided. Thermal bridges which can not be avoided must be minimesd as few as possible.