The passive house ‘LS30’ multi family residence in Darmstadt

Wandering the streets of Darmstadt, I discovered several beautiful energy efficient houses. One of them hidden between old baroque-style houses in the Martinsviertel, one of the oldest districts of the city.

On one of the last vacant properies in the Martinsviertel, two constructor companies fulfilled their vision of a family-friendly & ecological living in an urban environment. The “LS30” multi family residence, placed in an L-shaped plot, has eight apartments of variable size, individually tailored to the needs and expectations of their habitants.

The architect Corinna Bauer in order to meet the various requirements and client wishes in terms of housing size, location, orientation and equipment, designed the apartments to fit together like a complicated three-dimensional Jigsaw puzzle.

The residential building consists of two seperate apartment blocks. The courtyard block was constructed according to the Passive House standard and the front block, which faces the street, was constructed according to the KFW40 Energy Efficient standard.

The apartment blocks form a green, communal courtyard. Through a gated entrance one arrives in the intimate, green courtyard with bicycle and car parking spaces and variously configured and utilized gardens. The apartments in the courtyard  block are easily modifiable: If the children move out, their rooms can be separated to independent living units with bathroom (e.g. for a carer) and the maisonettes can be separated into flats. To get the individual wishes and needs of the families under one roof, was not easy – but living together works very well today. The laundry room, the workshop with yard and garden are being used without problems.

The contemporary, clean-lined rectangular exterior of the courtyard block might at first seem to be at odds with its surrounding, but the facade, an interwoven matrix of permeable wire-mesh balconies, red and black metal cladding, and various size windows, gives the building the subtle balance of form, function, materiality and light.

Ecological aspects:

Photovoltaic system on the roof of the courtyard house
Green roof
Rainwater is used for garden irrigation and infiltration


The balconies and the garden provide a perfect ‘settle’ to enjoy the mornings, afternoons, and evenings while floor-to-ceiling glass helps fill all the units at the courtyard block with plenty of natural light.

Selected project details of the Certified Passive House courtyard house:

Architect: Dipl.-Ing Architect BDA Corinna Bauer
Building services: Krauss + Brunnengraber
Building physics: Dipl.-Ing Architect BDA Corinna Bauer
Statics: Dr. Ing. Keller

Construction type: masonry construction with thermal insulation composite system
Annual heating demand (PHPP): 15 kWh / (m2a)
Heating load (PHPP): 12 W/m2
Primary energy requirement (PHPP):  107 kWh / (m2a) on heating installation, domestic hot water, household electricity and auxiliary electricity
Air tightness (PHPP):  n50 = 0.5/h
Basement floor /floor slab: tiles 10mm and 45mm screed followed beneath 240mm insulation and pre-cast 300mm concrete slab. U-value: 0.15 W/m2K
Walls: 175mm beton/Sand-lime brick with 300mm thermal insulation and 15mm plaster render externally. Internal 15mm wet plaster forming airtightness layer. U-value: 0.11 W/m2K
Roof: 10 mm gypsum fiber board followed under rafter insulation 100 mm, inter-rafter insulation 260 mm. U value (hall roof): 0.10 W / m²K
Windows frames: Pazen, Enersign Passive House certified component timber-fiberglass profile U-value: 0.79 W/m2K
Glazing: triple heat-insulated glazing, thermally separated with plastic edge seal. U g-value = 0.53 W / (m2K), g -value = 52%
Entrance door: Pazen, Enersign-door Passive House certified component timber-fiberglass profile. U-value: 0.8 W/m2K
Ventilation: Paul, Climos 150 DC, Multi 150 DC, Atmos 175DC decentralized ventilation system with heat recovery. Passive House Institute certified to have heat recovery rate of 90%
Heating installation: Air heating via preheater, electric. The coverage of the residual heating demand is performed in the plurality via a solid fuel stove. In addition, most apartments have electrically operated underfloor heating in the bathroom, for particularly cold morning hours.
Domestic hot water: decentralized instant hot water heater
Front building: geothermal heat pump system