Company Makrowin, after the evaluation of the notes from the customers, started to develop the wooden window, which can meet the needs of the passive house. Utilizing the experience of the company gained from the using of the wooden window Makrowin88, which is projected for the low energy houses, the frame of the window was improved in order to fulfill the strict criterion in passive house. This new developed window /or the frame of the window/ Makrowin88G2 was rated in the PHI in Darmstadt and after all tests this window was given a certificate of quality. This kind of Certificate is given only for the top quality products and in Eastern Europe there is only a few holders of it.For the passive house there is stimulated need of heat 15 kWh/m2 per year. The needs laid on the Windows for the implementation into this kind of houses are according to the PHI in Darmstadt very strict. (The Passivhouse Institut was established in 1996 by DR. Wolfgang Feist and it was established as an independent body. Institut offers advices and support for development and planning of the passive houses, gives the certificates and analysis for this houses or for the components. More info www.passiv.de). The loss of heat of top quality passive house is about 1,4 to 1,6 kW. It is so small loss, that for the comfortable warm ambiance there is a need to recuperate the air and to heat up the air in the process of recuperation for example with the electronic spiral or with integrated storage of heat. Temperature of such heated air is less than 40 grad of Celsius. While the outside temperature is low, a person is very sensitive to the most cool objects they are around him. The frame of the window is in the wall of the passive house the element with the lowest surface temperature that is why it has to meet very strict criterion. These criterion are very hard to reach and the fulfillment of them needs a long term development and experience.