Low-energy and passive house

The passive house is a concept of the future, even though such buildings have been built in developed countries for some 15 years. Passive houses are so well insulated that they need no radiators or air-heating system. They therefore use extremely little energy, while being very comfortable to live in, in winter and in summer.

The key features of a passive house:

• Outstanding thermal insulation of walls, floors and roof
• No thermal bridges
• An airtight building envelope
• Comfort ventilation (which makes window ventilation unnecessary)

The energy criterion for a passive house:

Maximum annual heating demand ≤ 15 kWh/(m²a) — roughly 1.5 litres of heating oil per m² of living space per year.

The passive house standard relies on a system that extracts used air and supplies fresh air, bringing the necessary heat into the building with the fresh air. The remaining small heat losses (from air movement) are compensated by almost "free" passive energy gains.

Passive energy gains:

• Sunčevo zračenje kroz prozore i ostale transparentne površine
• Predaja toplote kroz veštačko osvetljenje i rad električnih uređaja u kući
• Telesna toplota osoba koje borave u kući

The passive house standard relies on a system that extracts used air and supplies fresh air, bringing the necessary heat into the building with the fresh air. The remaining small heat losses (from air movement) are compensated by almost "free" passive energy gains.

Passive energy gains:

• Sunčevo zračenje kroz prozore i ostale transparentne površine
• Predaja toplote kroz veštačko osvetljenje i rad električnih uređaja u kući
• Telesna toplota osoba koje borave u kući

Wall, floor and roof insulation in a passive house:

As an example we take a house with a basement that is not used as permanent living space:

• Perimetarna termoizolacija (izolacija spoljnih podrumskih zidova) uz pomoć Austrotherm XPS P debljine 16cm
• Termička izolacija ploče iznad podruma uz pomoć Austrotherm EPS A100 debljine 25cm
• Termička izolacija spoljnih fasadnih zidova uz pomoć Austrotherm EPS AF debljine 25cm, ili Austrotherm EPS AF PLUS debljine 20cm
• Idealnu krovnu izolaciju

Windows and glazed doors:

In a passive house the windows and all glazed doors (e.g. terrace doors) must be of higher quality than in a normally insulated building. We recommend triple glazing.

No thermal bridges:

Edges, corners, joints and openings must be well insulated to avoid thermal bridges, i.e. heat loss.

A compact, airtight building:

Construction details at the joints between doors (windows) and walls make the building airtight, so outside air cannot pass through gaps and openings.

Comfort ventilation:

Its purpose is to keep harmful substances and other negative atmospheric influences on health as low as possible.

• Potrebno je obezediti priliv 30 m³ svežeg vazduha po času, za svaku osobu koja boravi u prostoru
• Provetravanje obezbeđuje higijenski čist vazduh, a sa razmenjivačem toplote se štedi i energija
• Zanemarivo prisustvo prašine i zdravstvenog opterećenja kojeg vrši na čoveka
• Sprečavanje prodora čestica vazduha iz spoljašnosti na koje su neki ljudi alergični
• Razni neprijatni mirisi, uključujući i dim od cigareta bivaju "usisani" i ne šire se po čitavoj kući
• U kući nikada nema promaje

A passive house is not tied to a particular style or method of construction. There are passive houses with solid walls, in timber or in a combination of both, and many European makers of prefabricated houses offer passive houses. The concept is not limited to new buildings either — it can also be applied when refurbishing old ones.

Fifteen years ago a passive house cost considerably more to build than a building with standard insulation. With better technology and more advanced building components, the cost has fallen. As passive houses are meant to last 50 to 100 years, and energy prices will certainly rise (perhaps drastically), there is no doubt that building passive houses will pay off even better in future than it does today — though it is already very much in demand.