Kalbreite Innenhof

Sustainability in today’s operations

As a Minergie-P eco construction, Kalkbreite meets high energy and ecological standards. It requires little heat input, which is made possible through a groundwater heat pump. Around 15 % of the electricity is produced by the photovoltaic system located on the rooftop. While features such as comfort and energy efficiency are inherent to MINERGIE-buildings, certified buildings according to MINERGIE-P-ECO standards also meet the requirements of a resilient and ecological construction, which require the disclosure of “grey energy” content. While the cooperative has taken a big step in the right direction in terms of construction, optimal energy conservation can only be achieved during operation. This depends on how much apartments are heated, how tenants ventilate them, if they unnecessarily leave light on, how much hot water they consume, and much more.



The cooperative largely refrains from regulations on reduced resource consumption and focuses above all on self-responsibility and sensitization. Resource consumption can be calculated using various instruments, e.g. the Novatlantis ECO2-calculator or the WWF-Footprint-calculator. Tenants thus receive tips about consumption in areas such as housing, mobility, utilization and nutrition. Consumption includes a proportion of “grey energy” which can only be influenced to a very limited extent, but which should nevertheless be included in consumer behavior. The consumption of “grey energy” can be improved through conscious shopping, avoiding unnecessary purchases and the economical use of consumer appliances.



Besides housing, mobility is the largest energy consumer in our society. The need for mobility is very individual and therefore an area of sustainability that is difficult to influence. The cooperative has taken various measures to make it easier for tenants to consciously deal with their mobility:



  • The Kalkbreite has a mobility concept that obliges residents “not to own a car during the rental period or use a car frequently”. Those working at Kalkbreite are also encouraged not to drive a care to work.
  • The car waiver (german only), a central part of the mobility concept, is a mobility fund through which tenants are provided with electric bicycles, trailers, bikes, etc. for hire and other amenities such as a bicycle service station, reception service for purchases, mobility information, etc. The mobility fund is also used to provide the tenants with the necessary information (available at the reception).
  • By saving on parking spaces, “grey energy” consumption during construction was significantly reduced. In addition, cleaning, lighting and maintenance costs are saved during operation.
  • The optimal connection to public transport by tram, bus and train offers the best conditions for a car-free zone.
  • Approximately 300 ground-level bicycle parking spaces in the house facilitate the use of bicycles.
  • Two parking spaces are available in the house for people with disabilities. An additional ten parking spaces are currently being rented in the urban neighborhood of Lochergut. Commercial tenants, guests staying at the guesthouse, renters of the Flex meeting rooms as well as by residents who have good reason for owning a car can rent these parking spaces.
  • Car-sharing and car rental services such as Mobility is recommended. In the immediate vicinity of Kalkbreite there are various Mobility locations.

In order to earn a 2000-watt society certification, it is essential that all residents minimize their mobility energy consumption. This includes frequent air travel as well train travel, which also consumes considerable amounts of energy, especially daily commuting.

Space consumption


At Kalkbreite, the average individual area consumption per person, including shared areas, is 33.5 m2. This is significantly lower than the usual 45 m2 (41m2 in Zurich) space consumption per capita for today’s new buildings. Due to the positioning (large building depth of 16.5 m and problematic corners), the Kalkbreite premises tend to be too large, which makes it more difficult to achieve this objective. This is compensated by the relatively large proportion of apartments with 5 or more individual rooms, in which space consumption is lower than in apartments with 1 to 4 rooms.


In addition to the residential and commercial areas, the common areas help reduce individual space consumption:

  • The shared office space reduces the need for an office area in the apartments.
  • Guestrooms in the Guesthouse Kalkbreite make visitor rooms in the apartments superfluous.
  • Residential joker can be rented and cancelled at short notice in various situations, e.g. teenagers getting older, couples break up, friends or relative moving in.
  • 4 boxes with no predetermined use offer free space outside the apartments, e.g. for communal play, television, yoga, sewing, etc.
  • The garden kitchen, cafeteria, library, sauna, Laundromat, workshop and music room are further common areas which support the reduction of individual space consumption and increase living comfort.

The most important parameter for achieving the objective of 35 m² / person is the minimum occupancy requirement in the apartments – number of rooms minus 1 (further information on this can be found in the Rental Regulations (german only).



Hot water treatment consumes more energy than heating. At Kalkbreite it is produced with heat pumps and stored in storage tanks per staircase. There are no solar collectors for water heating. The photovoltaic system is used solely for the production of general electricity and supplies around 20 % of the energy required for this.



Technical facts about construction and operation:

  • The water is heated by four heat pumps, producing heat from the groundwater.
  • In winter, heat pumps heat the water to 30° for heaters while the hot water pumps heat the water to the legally required 60°.
  • In summer, the hot water heat pumps extract the heat from the floor heating circuit. As a side effect, the rooms are lightly cooled.
  • The efficiency of the heat pump is measured with the annual coefficient of performance (COP). It indicates the ratio of the heating energy emitted over the year to the electrical energy absorbed. The COP of hot water treatment at Kalkbreites is 3.5. This means that 3.5 KWh of hot water are produced from 1 KWh of electricity.
  • Hot and cold water consumption is measured.
  • The building custodian monitors the energy consumption level of the apartments. There is no automated recording.
  • The meters are visible in the apartments. Apartments located the staircases have two counters.
  • All valves are equipped with “ecototal+”, which reduce the water flow by adding air. In the default setting, the mixer faucets are set to cold water. A small resistance must be overturned when turning the control lever in the direction of hot water. This prevents warm water from flowing out unintentionally.
  • The common WC facilities are only equipped with cold water. Hot water is available in the cleaning room next door. The facilities are equipped with waterless urinals that function without water, electricity or chemicals.
  • Some of the small apartments only have showers. By eliminating the full bathtub and using a low-energy shower head, hot water consumption can be reduced by approx. 60 %.
  • Instead of private washing machine connections, the Kalkbreite provides a Laundromat and two additional common washing machines per staircase. This not only saves “grey energy”, but also time as several machines can be used at the same time.
  • Rainwater utilization is only intended for the irrigation of the rooftop gardens, not for WC facilities, as the roof area is too small to function profitably.



The heating is designed for a comfort temperature of 20° C in the living rooms and bedrooms and 21° C in the bathrooms at – 8° C outdoor temperature. Kalkbreite is a so-called 3 liter house, e.g. a conventional heating system consumes a maximum of 3 litres of oil per m2 and year, or approx. 30 kWh/m2/year. This is about five times less than an average house or ten times less than an un-refurbished house built between 1960 and 1980. User behavior is crucial for achieving sustainability. In the event of negligence, such as inappropriate ventilation, cooling, etc., deviations of several 100% are possible. In summer as in winter, there is a danger that the apartments will overheat when exposed to sunlight and not properly protected. The sun can warm up rooms very quickly and the buildings insulation makes it difficult to dissipate the excess heat. Putting down the blinds is therefore necessary in the summer.



Technical facts about construction and operation:

  • Heating with groundwater heat pump at a temperature flow of max. 30°.
  • Heat distribution with floor heating.
  • Self-regulating heating system without direct regulation is possible for the tenants. The power can only be reduced by lowering the inflow. This regulation is very slow and is only suitable for the basic setting and not for daily temperature adjustments.
  • No individual measurement of heating per apartment or commercial space.
  • Easy cooling of the rooms in summer by extracting heat from the floor heating to generate hot water.
  • The efficiency of the heat pump is measured with the annual coefficient of performance (COP). It indicates the ratio of the heating energy emitted over the year to the electrical energy absorbed. The COP of the heating capacity Kalkbreite is 6.54. This means that 6.54 KWh of hot water heating energy/heating heat is produced from 1 KWh of
  • Information on ventilation and sun protection is available at the reception.



The Kalkbreite residential and commercial building has a comfort ventilation system which ensures constant, low air exchange filtered with outside air. Heat exchangers extract the heat from the exhaust air, preheating the supply air. This allows tenants the comfort of sleeping with the window closed. Of course, all windows can still be opened. In both summer and winter there is a risk of overheating if the shutters are not used correctly. The sun can warm up the rooms very quickly. Because the building is well insulated, it is difficult to dissipate excess heat. Hence, disciplined shading during the day is necessary in the summer.



Technical facts about construction and operation:

  • Central ventilation systems for the apartments are located in the technical center on the rooftop.
  • The ventilation systems for commercial spaces are located in the basement.
  • In the apartments, the ventilation distribution is inserted into the ceilings. The distribution boxes are visibly attached to the ceiling in the bathrooms.
  • In the commercial spaces, the ventilation distribution is visibly attached to the ceilings.
  • Tenants cannot directly influence the ventilation.
  • There is no individual measurement of ventilation per flat/commercial space.
  • Cooling of particular commercial establishments with groundwater is possible (max. 150 KW).
  • Information on ventilation and sun protection is available at the reception.



The energy consumption of electricity, hot and cold water, heating and waste is measured and shown in an annual utility bill. This allows users to monitor their total consumption and manage their progress towards 2,000 watts. On request, the hub can provide detailed data on individual consumption and suggestions for reducing consumption.


Private electricity consumption consists of the following elements:

  • Private lighting fixtures of the tenants
  • Use of private appliances such as computers, kitchen machines, vacuum cleaners, etc.
  • Usage frequency and duration of built-in kitchen appliances
  • Use of washing machines and tumble dryers

Technical facts about construction and operation:

  • The appliances installed in kitchens, laundries rooms, etc. at Kalkbreite are among the most economical on the market.
  • The basic standard of the kitchens is very low so that no unused appliances (“grey energy”) are left in the apartments. The standard can be individually adapted via the offered extension modules.
  • Apartment refrigerators do not have freezers. A common freezer (Freeze) with heat recovery is available in the basement. A considerable part of the hot water is heated through recovered heat.
  • All apartments have a power switch at the apartment door. When leaving the apartment, the power supply to predefined sockets can be interrupted by pressing a switch, which switches off all connected devices.
  • Energy-saving lighting is offered as an extension module (e.g. for bath, WC, shower and the central areas of apartments).
  • Smart metering (installation of meters in the apartment that make electricity consumption visible) is possible.
  • Energy-saving lamps sold at favorable price at the reception.

Community Electricity

Community electricity consumption includes:

  • Pumps (e.g. heating, water)
  • Motors (e.g. ventilation)
  • Lighting of common areas and outdoor areas

The photovoltaic system produces approx. 15 % of the common electricity consumption.

Technical facts about construction and operation:

  • Installation of efficient pumps and motors.
  • Minimal, economical lighting with motion detectors and daylight control.
  • 100 % of the electricity purchased comes from renewable sources (“EWZ nature made star”).


Waste & Recycling


The glass recycling area is a few meters away at Lochergut, at the corner of Badenerstrasse and Seebahnstrasse. The city of Zurich is responsible for the removal of green waste. The disposal of paper, cardboard, batteries and other waste materials is regulated by the city of Zurich and the reception desk.



Technical facts about construction and operation:

  • There are three sub-floor containers for household garbage and green waste on Badenerstrasse near the bicycle entrance.
  • Temporaty storage for residual materials is provided at various locations in the building, such as in the bicycle parking area and near the stairwells.

Group «easy living»

There are many good ideas for reducing individual resource consumption and it is important to implement them. This is what the residential group “easy living” advocates. It address the topic and makes the Kalkbreite public aware by brining it up in conversation. The “easy living” group follows the principle of sufficiency, i.e. the reorganization of consumption. Every conversion is initially difficult, but can soon become a matter of course. The group wants to show that sufficiency is not a hassle, but rather fun. It opens up new perspectives and leads to greater autonomy and freedom. The group has developed concepts for measuring and optimizing a personal life cycle assessment, which is tested and continuously improved by the group members. The results are regularly compared and discussed, and a balance sheet is drawn up periodically.



Topics and experiences are discussed in the General Council, in the Board and in other committees of the cooperative. The group is part of the broad participatory process that ensures social, environmental and economic sustainability in the operations of Kalkbreite. It sees itself as an open group and is committed to volunteer work. The group discusses its findings both internally and externally, and networks with other player in the city, in research and on the Internet. The group also actively writes, speaks, publishes and organizes events. In order to monitor and improve resource consumption, educate residents and create incentive systems and other measures, it cooperates with the reception desk. Conversely, the cooperative and the committees involve the “easy living” group in the advisory of resource consumption issues.

Further information on participation