There is no more convincing response to the operation of passive houses from that  which given by the users themselves.The letter below came via email from Lefteris the owner of our new passive house in Porto Rafti. The prefabricated passive house is 150 m2; the heating is mainly from solar panels which heat water at buffer tank for domestic use (DHW) and to preheat the air circulating in the house with a simple air-water exchanger. Also the passive house has a fireplace as backup 9kw. The radiator that referred by Lefteris is a small electric convector of 2kW that places in the living room to not open the electric resistance of the ventilation system which is 3 kW.

Read and enjoy it.

"Regarding the functioning of the house, it is really impressive ! I do not have a thermometer yet but in order to understand i tell you that, we walk around always with shirts and light clothing , we take a bath and we continue to walk around wet without the slightest feeling of cold.

Generally if we have 2-3 hours sun the house works alone. We turn on only at 11pm, the radiator low at 700w, but our little son Bampinos awoke sweaty 2 mornings. Yesterday with the snow at the morning, we had practically use only the radiator and we put a light sweatshirt. After I lit the fireplace (turn off the radiator!) and in 20 minutes we came back to summer again all day. The heat remained until the next morning (I turn off the fireplace at 11 o’clock), and today we were with shirts again. (I put again the radiator very low at 6 am).

Besides that the thermal comfort and the warm water is permanent, although we had cloudy days. There was  only  one case to turn on the water heater and that is to have our bath at the same time, or to fill the whole bathtub with very hot water. Yesterday though outside it was 2C and cloudy the water when I was looked was up to  45C .

As for the ventilation, I have said before, it's fantastic that you do not need to go out for a cigarette, and  we have continuously fresh air . It is very big advantage for a house, 2 times for a smoker and especially for parents.

Finally the layout is excellent. Beyond that helps us to heat the house quickly, the house is so comfortable either there are two people inside or 10. We made and polygon and storage facilities seem to be enough, the ladder has fit everything!

I hope to have given you a full image for those  early days of operation. "


The first prefabricated house of nearly zero energy consumption ΝΖΕΒ (Nearly Zero Energy Building), which designed by Passive House philosophy,  constructed by Easy Green in Porto Rafti at Attica region.  This residence is one of the few passive house residences already built in Greece (no more of 10) and it is the first Passive House built with the prefabrication method. It has an air ventilation system with heat recovery up to 81% in combination with water-air exchanger which is heated by

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solar panels. The combination of this systems in addition to high thermal comfort, to stable humidity and good ventilation will ensure nearly zero energy consumption. At the ventilation system a typical geothermal system will also be adapted for cool air in the summer and warm air in the winter.  The needed hot water will covered entirely from  8m²  solar panels in combination with a 500lt inertia tank.  The construction will be completed in almost 40 days.