Detached single family Passive House in Volos, Greece

My last visit to the city I grew up was very interesting and productive. I had the opportunity to visit a brand new Passive House designed by X-G group. The new house sits beautifully into the urban district of N. Ionia in Volos, Greece.

This simple and graceful new residence fulfills the Passive House standard  and is a high quality living space with low operation costs thanks to a combination of superb detailing in the design process and the fabric first building design.

Moreover, X-G group aimed to minimize the need for energy consumption through methods such as:

• Maximum thicknesses of insulation requirements
• Thermal bridge free construction
• Careful airtightness detailing
• Optimizing solar gain through the provision of openings and shading
• Using the thermal mass of the envelope
• Non-implementation of projections on the walls of a building or overhangs
• Reducing as far as possible the exposure of the building envelope to the elements of nature by adding adjacent non-heated auxiliary spaces
• Using the energy from occupants, electronic devices, cookers and so on

Design-wise, the finished result is a beautiful, bright, modern minimal 299 m2 house which manages to achieve superb energy efficiency. Moreover, the three bedroom home efficiently delivers spoils such as excellent indoor air quality, thermal comfort and low energy bills.

Architecture design

The house consists of four autonomous volumes that interlink, forming a courtyard at the south side of the property.

The main volume consist of an open-plan living adjacent to kitchen space, a master bedroom with a private bathroom, a guest room and a small WC on the ground floor. A metal staircase with wood cladding leads to two bedrooms and a bathroom in the upper floor.

On the southern side the second volume of the residence contains the parking and storage space. This ingeniously built-in storage space adjacent to the Passive House enhances the thermal resistance of the housing envelope.

The third volume on the west side is designed and constructed as a solar space. Due to its orientation, its south glass facade facing the courtyard maximizes the houses passive solar heating. The glass surfaces can seal in the winter improving the energy performance of the building. In summer, the solar space is protected against radiation via a motorized roller blinds system.

The fourth volume on the east is a semi-open construction housing the main entrance of the residence. It protects the housing envelope from the elements of nature.

Mechanical Systems

The living space is divided into four thermal zones, each one with temperature control capability, so that different space-conditioning requirements, heating and cooling set point / temperatures can be selected in each space.

The building’s main space heating system consists of a heat generation GAS condensing boiler. The space heating is provided by three towel radiators, 700 calories each, which are installed one in each bath. Internal walls between baths and bedrooms transfer small amounts of heat required in the bedrooms while at the same time ensuring a 2 °C higher temperature in the baths, a requirement imposed by international thermal comfort standards.

In the kitchen the thermal energy released from electrical appliances (for lighting and cooking) suffices for space heating. It is also protected from the solar heat. In the basement the thermal energy dissipated by the fixed mechanical equipment is also sufficient for space heating.

Ventilation system with heat recovery, ensuring that the indoor air is constantly replaced with fresh air, while saving significant amounts of energy. The special features of the system (Bypass, subsoil heat exchanger “air-soil” by REHAU eff. specif. HRE: 82%) contribute to the maintenance of thermal comfort,  while allowing the system to provide, beside fresh air, significant amounts of heating in the winter and cooling in the summer.

To ensure cooling during the summer months, air conditioners were installed, one on each floor.

Additionally, a key installation is the motorized roller blinds system that allows or prevents the entry of solar radiation as you please without preventing the natural light and the view from the yard.

Hot water is supplied via a GAS condensing boiler and a thermal solar collector with surface area: 5,2m² (DHW distribution in circulation pipes). The solar panels are located on the roof of the building and the hot water tank in the basement.

(clockwise from top left) Installation of EPS (033) from 200mm to 350mm insulated foundation system to provide continuous insulation thereby reducing heat flow and improving energy efficiency. (next image) Reinforced concrete slabs form the basement and ground floor of the building, insulated above with EPS (033) from 150mm to 200mm and poured lightweight concrete 40mm. The foundation walls and concrete slabs have damp proofing membrane applied to the exterior insulation to prevent damaging wetness and moisture from seeping in through the walls but also help to rid the house of residual moisture. (next image) Masonry construction. (next 2 images) Applying EPS (033) from 200mm to 350mm on the external walls of the building. (last image) A wet plaster finish is used for the airtight layer of the walls. Plaster is inherently airtight, as is concrete. Plaster finish is used in a masonry construction to create a continuous and effective airtight layer. Also in the picture metal battens forming a ceiling service cavity through which the rigid MVHR ductwork runs. A good airtight seal around pipes where they pass through the external wall.

Selected Project Details

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Architecture design: Stefan Thomas Chatzoulis / XG group of engineers

Statics: Christine Georgiadi / XG group of engineers

Main contractor: Stefan Thomas Chatzoulis / XG group of engineers

Buildings physics: Stefan Thomas Chatzoulis / XG group of engineers

Detailing: Stefan Thomas Chatzoulis / XG group of engineers

Photo: © George Goutzoulias / Light Box

In Detail

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Building type: 299,24 sqm detached single family house

Location: Volos, Magnesia, Greece

Completion date: 2017

Annual heating energy demand: 11 KWh/m²y

Heating load = 13 W/m²

Annual cooling energy demand: 13 KWh/m²y

Cooling load = 9 W/m²

Primary energy requirement: 66 kWh /(m²a ) on heating installation, domestic hot water, household electricity and auxiliary electricity calculated according to PHPP

Airtightness (@ 50 Pascals pressure): 0,54/h air changes per hour 

Exterior walls: brick 90mm, EPS (033) from 200mm to 350mm. Uwall = 0,126 W/(m²K)

Roof: reinforced concrete 150mm, EPS (033) 300mm. Uceiling = 0,116 W/(m²K)

Basement floor / floor slab: light concrete 40mm, EPS (033) from 150mm to 200mm, reinforced concrete 300mm. Ufloor = 0,222 W/(m²K)

Windows: Uwindow = 1,019 W/(m²K)

Windows frame: KOEMMERLING, KBE 76, PVC double + single frame. U w-value = 0.88 W/(m²K). 

Windows glazing: Guardian – Climaguard 4/16/4/16/4 Ar90%. U g-value = 0.69 W/(m²K) g -value = 62 %

Heating system: Heat generation GAS condensing boiler

Ventilation: WOLF , CWL 300 EXCELLENT, Central balanced ventilation with HR & subsoil heat exchanger (air-soil) by REHAU, eff. specif. HRE: 82%

Image gallery

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