The Passive House is an integrated concept assuring the highest level of comfort, but it is not an energy standard. The definition that is applicable worldwide is as follows:
“A Passive House is a building, for which thermal comfort (ISO 7730) can be achieved solely by post-heating or post-cooling of the fresh air mass, which is required to achieve sufficient indoor air quality conditions – without the need for additional recirculation of air.” . That is to say, a building, which can be kept at a thermally comfortable level and is able to provide a sufficient indoor air quality by only using a minimum of air exchange by the ventilation system that, if needed, has an integrated heating or cooling device.
Originally the concept was based on the cool-temperate climate zone of Germany, and so the heating demand was used as a measurement. Since 15.04.2015 a new definition of the Passive House has been used. That will be explained in section 6. To explain the idea and the concept of a Passive House, the original definition is used in this section.
The Passive House Principle and Concept
The Passive House concept was developed in the early 1990s in Germany and successfully spread across Europe and beyond. The PH concept has a dual aim of low energy consumption and affordability. This objective should be mainly achieved by passive methods, such as thermal insulation, high-quality windows, airtightness and limitation of thermal bridging. In most cases, heat recovery ventilation is needed. The ventilation system that is required for hygiene can heat/cool the supply air efficiently in a Passive House. The higher cost for the high-quality building materials and systems can be reduced by eliminating the cost of the radiators, plumbing and the heating system that are not needed. The results for the slightly higher investment cost (between 0 and 15 percent) are buildings with extremely low energy consumption and optimal hygrothermal comfort. 
For certification by the Passive House Institute, the heating demand cannot exceed or the heating load may not exceed. Further requirements are that the total primary energy consumption of the building stays below and the airtightness with air exchanges does not exceed 0.6 per hour at of differential pressure. Throughout the present report, these values refer to the living area, i.e. the net floor area of all rooms within the thermal envelope excluding the walls and staircases. 
Energy efficiency and consumption in a Passive House
Air, as a heating fluid, has a limited heat capacity. The heat capacity of air at normal pressure and is . The fresh air can be heated to a maximum of – higher temperatures can cause dust carbonization. According to DIN 1946, the minimum fresh air flow rate per person (hygiene condition) is . 
This comes to:
The heating capacity per person is 300 Watts. The average living space for one person is . This comes to the maximum heating capacity of and refers to the day with the highest heating load. Another important criterion is the annual heating demand, which is not allowed to exceed . Either one of these standards, or , needs to be fulfilled to meet the Passive House criteria.
(The average energy consumption in a 2.5-person household in Canada needs 101 gigajoules, and 63 percent are used for heating, which is a heating demand of .)
Overall, the primary energy demand in a Passive House cannot exceed The primary energy is the energy that needs to be provided to heat or cool the building, heat the domestic water, do the laundry, work the lighting and supply all other energy users in the building. 
This low energy consumption of a Passive House can only be achieved if the building components are designed for it.