a passive house

A passive house (PD) is characterized by very low energy consumption to ensure thermal comfort and for the entire operation - ideally, it is enough to heat (or cool) the ventilation air to heat it (or cool it in the summer). We define it with the following values:

specific heat demand for heating no more than 15 kWh/m2a (and/or heat loss below 10 W/m2) - calculated by PHPP software or in simulation

BlowerDoor test – air permeability test of the building envelope (BDT) with the value of hourly air exchange with leaks n50 at most 0.6 times the volume of the measured space

the need for primary energy (including electrical appliances) no more than 120 kWh/m2a

The characteristics of a passive house describe the quality of the outer shell and structural solution - these are not unambiguously defined values ​​and conditions, as they are also related to the size of the object and its architectural design, but we often also state them: The coefficient of heat transfer "U" of opaque perimeter structures should be below 0 .15 W/(m2K). For a family house, in our climatic conditions, it must be less than 0.1 W/(m2K)), the "U" factor of the windows should be below 0.8 W/(m2K) and if we want to count on the passive use of solar gains, they should windows should let in at least half of the solar energy (g > 0.5). The building should be designed without thermal bridges and with controlled ventilation with heat recovery (recovery) from the ventilated air (minimum efficiency of the recovery unit 80%). Solar collectors or the use of a heat pump can significantly contribute to reducing the need for primary energy.

The uniqueness of a passive house lies in the efficient use of local energy sources of heat, in particular:

in the passive use of solar energy,

in the use of internal heat sources (residents, appliances),

in the re-use of heat from the indoor air - recuperation

Such energy gains can be achieved mainly thanks to:

thermal insulation of packaging heat exchange constructions (U < 0.15W/m2K),

windows with excellently insulated frames (Uw around 0.8W/(m2K)),

elimination of thermal bridges in constructions,

airtightness of the envelope, heat exchange constructions of the building - air permeability less than 0.6 times the volume of the measured space in 1 hour with a difference in external and internal air pressures of 50 Pa (i.e. n50 < 0.6 /h),

controlled ventilation with heat recovery (with a minimum effective 80% efficiency).

At first glance, a passive house is no different from an ordinary house - from a construction-technological point of view, it is "only" an improvement of the so-called low-energy house. However, higher demands are placed on PD in terms of design preparation, care in the development of construction details, excluding thermal bridges and leaks. Professional implementation without any deviations from the project documentation is especially important.

active house, multi-comfort house

The term "passive house" is not legally protected or enshrined in legislation in most countries - it relies on the authority of PHI Darmstadt and cooperating organizations. Several companies pursue similar goals with almost the same means (physics applies), for marketing reasons and also to emphasize specific approaches, they introduce terms such as "Active House" (Velux) or "Multi-Comfort House" (ISOVER) to denote their version of PD.

These solutions, like the concept of houses with almost zero energy needs, are based on the principles of passive houses.

These texts are a joint work of the Institute for Energy Passive Houses according to Act 618/2003 Coll. Any reproduction of the work or its parts (with the exception of exact citation with source) is possible only with the written consent of the Institute.

https://iepd.sk/