A growing emphasis is placed on eco-friendly and energy self-sufficient houses with an extremely pleasant living atmosphere, so-called passive houses. Passive houses must maintain a heating consumption below 15 kWh/m2a per year. The heat used is collected with heat pumps, from the passing of the sun's rays through the window glazing and of course by collecting the heat from other installed devices as well as from the body heat of the home's inhabitants. The extremely pleasant atmosphere is created by constant air circulation; the loss of the heat is minimal due to this closed system. The usage of return heat can be as high as 90%.

Windows and doors that meet these high performance criteria must have a heat loss/gain under 0.8 W/m2K for the whole unit; heat loss/gain through the glazing must be a minimum of Ug = 0.7 W/m2K. It is also essential that the products are installed as per RAL guidelines. When building a passive house, the initial investment may seem too expensive when calculating the costs of construction, but studies show that due to ever increasing energy product costs, the investment is returned in only a few years. We must also consider that trends in modern construction are constantly changing and are getting closer and closer to meeting the criteria for passive construction. It is only a matter of time until passive construction becomes the rule rather than the exception. An important fact to consider is that it has been suggested to the European Parliament that all new construction shall use passive technology from 2011 onwards (Article 29 of European Parliament Resolution 2007/2106).