• Building Type : Terraced Individual housing
  • Construction Year : 2015
  • Delivery year : 2015
  • Address 1 - street : 15669 PAPAGOS, Greece
  • Climate zone : [Csb] Coastal Mediterranean - Mild with cool, dry summer.

  • Net Floor Area : 114 m2
  • Construction/refurbishment cost : 57 150 €
  • Cost/m2 : 501.32 €/m2

Certifications :

  • Primary energy need :
    85 kWhpe/m2.year
    (Calculation method : Other )
Energy consumption
Economical buildingBuilding
< 50A
51 à 90B
91 à 150C
151 à 230D
231 à 330E
331 à 450F
> 450G
Energy-intensive building
The existing building, a typical 1960´s Athens single-family house, was selected for a full refurbishment using Passivhaus standards. The bearing structure was originally made by reinforced concrete with no insulation in the walls, a flat roof with access from an external staircase and single-glazed windows with wooden frames. Oil stoves and conventional radiators, a traditional fireplace, two old cooling units and an electric water heater were used as the original HVAC and DHW systems. Before renovation, the building was unoccupied for at least 5 years and annual primary energy consumption was estimated around 300 kWh/m2.year.

For the project team the aim of “Passivistas: The House Project” was to be considered an exemplary case study for nZEB buildings in Greece reaching the objectives of the 2020 roadmap. The idea or objective that“consuming much less energy is achievable and cost effective” being paramount to the project. 
The energy upgrade was centered on achieving energy consumption targets defined by the EnerPHit standard criteria:
  • maximum needs for heating or cooling ≤ 15 kWh/m2.year
  • maximum total energy primary needs, including electricity consumption ≤ 120 kWh/m2.year
After renovation, the single-family house was converted into two separate spaces:
  • house (ground floor) comprised of a living room, kitchen, bathroom and two bedrooms. During the 7 consecutive years following the renovation, this space will act as an open residence for guided visits, lectures and presentations to public and professionals. 
  • office (semi-basement) comprised of a reception area, meeting room and bathroom. This space is to be used as the headquarters of the Hellenic Passive House Institute as well as a venue for seminars, training, and a materials showroom.

See more details about this project

Data reliability

3rd part certified



    Stefan Pallantzas

Construction Manager


    Stefan Pallantzas


    Certification company


    Ioannis Pappas

    Passive House Training , Consulting and Certification

Contracting method

Other methods

Owner approach of sustainability

  • The main energy efficiency measures carried out were the following: external insulation of the entire façade and roof
  • replacement of windows and frames with triple glazed windows
  • optimization of shading and solar gains through automatic blinds and a surrounding garden
  • improving airtightness of the building, paying special attention to even small amounts of uncontrolled leakage through frames, electrical and plumbing gaps by using methods such as airtight membranes sealed with special silicone
  • installation of a heat recovery ventilation system for each space (house and office) to improve the indoor air quality and for preheating or precooling the air
  • installation of a split cooling and heating system (one in the living room and other in the office) to cover occasional heating and cooling demand when necessary
  • installation of a solar thermal system for hot water
  • removal of conventional radiator system and all other old units, as well as the fireplace
  • use of energy efficient elements for the lighting system 
  • high-efficiency appliances
  • automatic display monitoring system for control and measures
  • installation of a PV system to cover all the energy consumption needs 

Architectural description

The building is located at the Municipality of Papagou, Athens  and was built back in 1964 on a 520 sq.m. corner plot, the two facades looking Northeast and Southeast. 

It consists of 2 units; a 98,80 sq.m. 2 bedroom private residence on the ground floor and a separate semi-basement 43,60 sq.m. storage/boiler room; the last one will be converted into an office.

The building doesn't have the perfect orientation and compactness, but the results after the renovation show that everything is possible , even in such a building, if you calculate well and with the right tools.  

If you had to do it again?

I would do exactly the same ! Me and my team have enjoyed this project, have learnt a lot and have grown our business. Me personally enjoy living in a passive house with perfect comfort conditions and very low energy consumption.

Building users opinion

If you live in a passive house, you are a lucky guy!
This project is a critical point on the road to the greek NZEB building of the 2020. We want to show to the people, to the engineers, to the market, to the government that consuming much less energy is achievable and cost effective. And after that, it's easy, using renewables sources, to achieve a house which has a positive energy balance that means a real sustainable house.
The way of design and step-by-step implementation, and the subsequent monitoring and metering project promotes collaborative processes among executives of HPHI, certified passive building designers, engineers and technicians from all sectors and commercial and technical department of companies manufacturing and marketing passive house components.
It offers to every citizen through open public data all the information required on how to drastically save energy in his house, while improving quality of life and contributing substantially to the fight against global warming.
After completion of the project the house acts as media and collaborative process hub aimed to prove in practice the ability to upgrade the energy consumption of residential buildings in Greece and the Mediterranean area , so they do not need conventional heating or air conditioning, while drastically reducing energy costs and improve the quality of life in them. And all this at an acceptable cost to the community. Specifically the project will implement the following action axes:
. The ground floor of the project acts as an open residence for seven consecutive years, open for guided visits, lectures and presentations to the public and to engineers, etc More than 1.500 have already visited the house.
· The space of the basement serves as headquarters of HPHI as well as a venue of seminars, training, materials showroom etc. We have done already 16 big courses and more than 100 architects and engineers were trained and certified here.
· HPHI created the project website and will cover via an interactive blog all steps and aspects of the project. On the website every citizen can be informed on how to design, stages of implementation, the specifications of materials and controls, and to see online measurements and actual operation and consumption of the building. On the other hand, all companies participated in the project will have access to all data available, concerning the behavior of the building, of all materials and equipment and will cooperate with HPHI and the project management in order to improve quality of their products.
The team developed media material available to everyone, videos, posters, pamphlets, a technical handbook etc. The building is the first certified as a EnerPHit Plus in the Mediterranean Area, which means it is the first Building in the region, producing more energy than consuming.
For now this amount of energy will be sold to public energy company via net metering, but in the future we are thinking of making the building totally autonomous.

Energy consumption

  • 85,00 kWhpe/m2.year
  • 623,00 kWhpe/m2.year
  • Other

  • 29,90 kWhfe/m2.year
  • Heating (incd. aux electricity of HP) = 6.6 Kwh/m2a
    Cooling and dehumidification (incd. aux electricity of HP): 5.55 Kwh/m2a
    DHW generation (electricity) : 2.2kWh/m2a
    Household electricity (appliances, lightning, ventilation) : 15.58 kWh/m2a

    We get 92% of DHW by solar panels. We produce more energy in average total yearly with our PV system , than we consume.

  • 300,00 kWhpe/m2.year

Envelope performance

  • 0,33 W.m-2.K-1
  • The enerPHit consists of:
    Roof, external insulation = 30 cm of EPS [λ=0,030 W/(mK)]
    Ext. walls, external insulation = 15 cm of EPS [λ=0,030 W/(mK)]
    Floor slabs, internal insulation = 5 cm of EPS [λ=0,030 W/(mK)]

  • 0,88
  • n50

  • 0,56

Real final energy consumption



    2 017


    • Heat pump
    • Canadian well
    • Solar Thermal
    • VRV Syst. (Variable refrigerant Volume)
    • Canadian well
    • Natural ventilation
    • Double flow heat exchanger
    • Canadian well
    • Solar photovoltaic
    • Solar Thermal
    • Heat pump
  • 127,00 %
  • We just use a single minisplit unit in the residence and another one in the office to heat and cool the building.

    Our PV system is just 3.5 KWp and covers total needs.
    Our solar system covers 92% of needs.

Smart Building

    The Building has a measuring system. We measure temperature and humidity, internal in three rooms and external, Co2 inside and Sound in and outside. We measure electrical consumption, for heating , cooling, DHW, appliances, ventilation. We have dat of 3 years and we publish them in our website every month.
    Having this online data, we use simple apps to control our heating/cooling/ventilation system via internet. So we can simple automatisation for cooling and heating , keeping the house always between 20 and 25 degrees Celsius.

GHG emissions

  • -13,78 KgCO2/m2/year
  • 172,50 KgCO2 /m2
  • 50,00 year(s)

Water management

  • 75,00 m3

Indoor Air quality

    Perfect conditions via mechanical ventilation with Heat recovery. F7 filters used for the incoming air, G4 filters used for the extracted air. 

Health & Comfort

    All envelop and windows calculations were done in order to minimize thermal bridges and any risk of mould. 

    600 ppm

    625 ppm

    between 20 - 25 degrees celsius according to PH standard.

    between 20 - 25 degrees celsius

    Under 35 db


    Pluggit AD160


    HVAC / Ventilazione, Raffrescamento

    Ventilation Unit with Heat Recovery

    Very good heat recovery performance , low noise!

    DAIKIN FTXM/RXM Mini Split



    HVAC / Ventilazione, Raffrescamento

    minisplit unit for heating/cooling , very good perfomance, R32 , the only A+++ at that moment in the market.

    It was the best product we found on the market with an extra ordinary SEER of 8 , which is real!

Construction and exploitation costs

  • 5 000,00
  • 57 150
  • 40 000

Energy bill

  • 150,00

Urban environment

The building is located in Papagou. The area is known as a low impact urban area , designed and developed during the 60's by the greek army for its personell. So the area was full of nice 500 m2 plots and single family houses. Papagou is the nearest suburb of this kind to the center of Athens. The area of the building is just 2 minutes or 500 meters to the highway conection, 20 minutes to the international athens airport and 1.5km or 20min by feet to the metro station and then 12 minutes to the center.  

Land plot area

520,00 m2

Built-up area

20,00 %

Green space


Parking spaces

2 parking places inside the plot

Building Environmental Quality

  • indoor air quality and health
  • consultation - cooperation
  • acoustics
  • comfort (visual, olfactive, thermal)
  • energy efficiency
  • renewable energies
  • maintenance
  • building end of life management
  • mobility
  • products and materials

Contest categories

Energy & Temperate Climates

Energy & Temperate Climates

Users' Choice

Users' Choice

Sustainable Renovation Grand Prize

Sustainable Renovation Grand Prize

Green Solutions Awards 2018 - Buildings

Author of the page

  • Stefan Pallantzas

    MsC Civil Engineer

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