Doleta is probably the earliest in Europe to produce wooden windows for the homes of the future. Already in 2006 the company received a certificate from the Germany Rosenheim Passive House Institute (ift Rosenheim) confirming that the heat transfer coefficient of its windows is less than Uw = 0.8 W/m2k – they are suitable even for a passive house. Last year, warm windows in Lithuanian sales accounted for about 70% of total production. The heat transfer coefficient of the hottest windows offered by the company is 0.51 W / m2k. In Lithuania from this year all new construction buildings must comply with energy efficiency class A++, i.e. Uw = 0.8 W/m2k.