Passive Habitat

The passive habitat is a concept initiated in 1990 by the engineer Wolfgang Feist to qualify a building whose energy consumption with the m ² very low, is even entirely compensated by the contributions solar or emitted by the internal contributions (electrical material and occupation).

A house passivates reduced approximately 80% the energy expenses of heating compared to a new house built according to the German standards of thermo isolation of 1995, very demanding standards already.

The purpose of program CEPHEUS (Cost Efficient Passivates Houses ace EUropean Standards) contributed to develop the concept of passive building, it was to promote this type of construction. Via this program, Europe financed achievements made in 5 countries: in Germany, in Austria, in France, in Switzerland and Sweden. Each country taking part was to prove technical feasibility and the profitability of the project and to allow the reproducibility of this type of construction.

History of the concept

The basic principles (passive walls and use of solar) go back to antiquity but they profit from new knowledge and materials. There existed already buildings energy savers (low-energy house), and a German standard ( Niedrigenergiehaus Passivhaus, in German), as well as Swedish or Danish standards very demanding and adapted to the cold countries. But the construction passivates became a standard of quality in several countries (Scandinavian Germany, Switzerland and countries in particular).

The concept of construction passivates was developed in the years 1970, but was formalized in 1988 by Pr Bo Adamson of the university of Lund, (Sweden) and Wolfgang Feist ( Institut fur Wohnen und Umwelt /Institute for Housing and the Environment). ) It was developed thanks to the assistances of the German Land of Hessen with a first line of 4 houses (with terraces) built for families, by the Professors and architects Bott, Ridder and Westermeyer. The concept was validated with Darmstadt, with a saving in heating of 90% compared to the standards of the time.
Puis an work group was created in 1996 to develop technically and economically the concept by planning the production of materials, labels or certification for the windows, like ventilation systems with high efficiencies. Passive houses were built with Stuttgart (1993), Naumberg, Wiesbaden, and Cologne (1997) and the die developed with the support of the European Union via the program CEPHEUS which validated the concept in 5 European countries the winter 2000 - 2001. Some processes were invented for construction passivates (ex: stuck hollow bricks of type Monomur). Standards and labels were especially created, others are simple improvements of techniques and existing technologies (surisolation for example).

Principles

The design of a passive habitat is based on six great principles:

reinforced Thermo isolation, windows of great quality
Suppression of the cold bridges
Excellente air tightness
Ventilation doubles flow with recovery of heat
optimal, but passive Captation of the solar energy and the calories of the ground
Limitation of consumption of energy of the domestic apparatuses

Thermo isolation

the Thermo isolation is the basic principle of the passive house . It must be highly powerful and applied to all the outer jacket of the building, without interruption nor breach in order to limit the bridges thermics. Construction must be rather compact in order to limit its external surface. All the opaque parts of the building are to be insulated in an optimal way. In theory for the central European climate, their overall heat transfer coefficient U should not exceed 0,15 W/m ² K but it is currently recommended that this value reaches the 0,10 W/m ² K. For comparison, the RT2005 (French Thermal Regulation) imposes a maximum of 0,45 W/m ² K and a value reference of 0,36 W/m ² K for the walls in contact with outside. The characteristics of the windows are also very important (it is useless to carry out a powerful insulation of the opaque parts if all is wasted by the transparent parts…). Indeed, the coefficient of transmission U should not exceed 0,8 W/m ² K what is much lower than the reference RT2005 which is of 1,8 W/m ² K with a limiting value of 2,6 W/m ² K. Taking into account these characteristics triple glazing is often used. More than the glazing in itself, it is the whole of the window which must be coherent. It should in particular be taken care that its installation in the frame is carried out " house passive" (it is not worthwhile to install an expensive glazing if all energy slips by between the frame and the window). For the French climate, a little softer than that of Germany, it is possible to reduce the value of U (wall, roof, ground, window) and to optimize it thanks to the calculations carried out with spreadsheet PHPP (Passivhaus Planning Package) provided by Passivhaus Institut.

Removal of the cold bridges

From the moment when the building is very seriously insulated, the thermal Ponts, i.e. the places where heat escapes more quickly than from others, must be limited to the maximum. Those must generally with the assembly of the elements carrying the building or with the balconies. In the passive house, it is a question of reducing these zones in a drastic way. Indeed on the level of insulation required by the concept of passive house, the possible cold bridges take an excessive share in the heat losses.

Air tightness

The losses by a bad air tightness can be very prejudicial with the energetic efficiency. The continuity of air tightness must be carefully studied as of the stage of the design, while paying an special attention with the connections between the elements, the bay framings and the penetrations (led chimney, drains.), with qualities of insulators, etc to check the good sealing of the building, one carries out after construction a Test of infiltrometry.

Ventilation

To limit the thermal losses implies to be isolated completely from outside. A system of ventilation to double-flow with recovery of heat installed in the passive house makes it possible to manage flows of air in the building and to heat or refresh the interior air. The use of a heat exchanger air/ground (well Canadian or of Provence or circuit water) makes it possible to preheat the air in winter and to refresh it in summer, before it enters the building. In intersaison, the temperature of comfort ranging between 18 and 22°C, the system will be shorted-circuit. Moreover a good ventilation makes it possible to limit the contact with the toxic products generated in the habitat and thus to better preserve its health. The exchanges of air recommended are 0,3 ACH (changes of air per hour), with beyond the air is too dry in winter. The low level of renewal implies a quality of the completions which minimizes the exposure to the COV' S, formaldehydes, etc

Solar liability

For to develop the potential provided by the sun in winter, in spring and in autumn, it is necessary to collect its heat, to store it and restore it. Solar energy is collected by the glazed parts of the house. These insulating glazings are dimensioned according to the orientation of the building: 40 to 60% of surface glazed on the southern frontage, 10 to 15% in north, and less than 20% on the frontages is and western. The solar energy, which penetrates via the windows, is stored inside by materials with strong inertia. The heat accumulated in the building must be restored in the part by convection and radiation, with a time-scale. In order to avoid the discomfort caused by overheatings in summer, the direct sunning of the frontages is to be controlled thanks to constructive solar protections (hood, sun visor, shutter,…) and with glazings with a sufficient solar factor to limit the energy contributions. These constructive measurements can be supplemented by blinds and a vegetable protection.

Sparing domestic apparatuses

Not to spend unnecessarily what was gained in addition, the concept of passive house fixes a maximum value of total energy consumption in term of consumed primary energy (what makes it possible each and everyone to think of the enormous losses of energy caused by the fossils energy utilization…) who generally requires the use of weak apparatuses consuming energy. If one uses electricity for example, 120 kWh (m2.an) of primary energy thus correspond to 120/2,58 (the coefficient of ratio primary energy/final energy that one knows well with the DPE) that is to say thus a maximum of 46 kWh (m2.an) of total intake of the house. As the heating takes of them already 15 kWh (m2.an), one realizes that it remains well little to conform to the concept of passive house. Thus the use of apparatuses énergétiquement effective becomes a requirement, which brings moreover the advantage of not constituting a parallel heating system.

Definition

The standard of passive house primarily aims at reducing consumption, altogether largely useless our houses. To qualify what was known as higher, " 3 critères" defining a house passivates were established as follows:

Consumption of energy of heating < 15 kWh (m2.an).
air tightness: test of the door (blower door). n50 < 0,6 h-1.
Total intake of energy of the house < 120 kWh (m2.an) of primary energy.

As it is seen, the concept of " house passive" corresponds to a dwelling with very low energy consumption.

Cost

A passive house costs between 7 and 15% of more than one traditional house. According to the cases, the investor returns in his expenses between ten and a score of years thanks to energy saving carried out.

Brakes

One of the identified brakes is the lack of qualified craftsmen, architects trained with these standards and the rise in the costs pulled by a demand which exceeds. To decrease the energy consumption of the buildings by 22% from here 2010 in Europe, a Directive " energy performance of the buildings " (EPBD) is in the course of transposition in 2007 in the national rights, it could possibly encourage the formation.

But the 1st Sitted Frenchwomen of passive construction, in 2007 aim at encouraging:

construction with the passive standard (what implies to better train the architects, craftsmen, the elected officials and owners building, etc),
the use of regional wood for local development and the reduction in the ecological print,
the support for the dies of production of passive construction, to answer the expectations of the market.

Stakes

The sector of the building is in Europe the first consumer of primary energy (40% of consumed total energy) in front of the Transport S (30%) and the Industrie (30%). It is responsible of more than 40% of the total emissions of CO2. Energy saving is an economic issue and ecological major for this sector. The passive houses and/or, or “ vigorously positive” which exists per thousands in Germany and Switzerland show that the technical solutions exist. Remain to generalize them to hold the objective of the Facteur 4, or Facteur 9 (to divide by 9 consumption for a service are equivalent). … Whereas the oil price and of energy should ineluctably increase (cf misses Pétrole, Manque of Uranium starting from 2024 according to IAEA). An European directive on the energy performance of the buildings aims at reducing their energy consumption of 22% from here 2010.

Criticisms

Principal criticisms made with the passive standards, are that they convey an image of high-quality, without imposing ecological quality nor social or in ethical term of trade as for materials used (toxicity, source) or with the labor and with health and safety with work (cf wages of the workmen, etc). This standard is sometimes confused besides with those of HQE, which are broader (14, even 15 targets) but less powerful at the energy level.
Les architectural forms, and is often considered to be less complex architecturalement poorer. This results from the will to have a compact building.
Because of the low number of opening windows of certain constructions, the claustrophobics can feel locked up in these houses (in addition very quite sound-proof), even if the renewal of air is often better assured there than in a traditional modern apartment. Element-plug of the veranda type and widened picture windows can attenuate or make disappear this feeling, but with an increase in cost to construction. This feeling often is in addition quickly compensated by a thermal and sound comfort increased.

See too

solar Maison passivates
HQE
Isolto
Glossaire of the real estate

External bonds

residential examples

Construction of passive houses in Alsace, France
Two certified passive houses with Formerie, France
a passive house in Nice, France
original Houses of Darmstadt

Other images of constructions in Darmstadt

In Germany and Austria (Residential)
Kama House One of the first passive houses of the United Kingdom.
Irish Examples
Waldsee BioHaus passive First houses certified in North America ([[Minnesota]).]
E-colab Passivates House projects, Urbana, [[Illinois].]

Another example in Illinois: Energy Design Update

Ecozap: Construction of residence with positive energy in the Vendée, France

general information

Informations on the principle of house passivates (France)
Site of the German institute PassivHaus
Brochure in French of Passivhaus Institut
the house passivates Site of an architect
the Platform House Passivates (Belgium)
the principle of the house passivates Site of an architect
the House Passivates France (France)
a passive house in Nice Actualités and project
a passive house in Belgium blog and project
IG Passivhaus Schweiz (Swiss)
Portail for the Minergie-P label (Swiss)
positive Energie, site dedicated to the building with Positive Energie
Portail ofECBCS, body created by the International agency of energy to encourage individual and collective energy saving ( Energy Conservation in Buildings and Community Systems )]
Calculation of sunning for the construction of passive houses

Random links: