The joinery provided at the application of multi-chamber window and door profiles from the FORIS family, guarantees perfect thermal insulation. During the wintertime, it will effectively retain the heat at home, and during the summertime, it will protect the interior from excessive heating and keep your home pleasantly cool. The perfect thermal insulation of the FORIS pvc joinery translates into significant reduction of heating costs during the winter and air conditioning during the summer heatwaves. The replacement of old windows will cause the heat losses to be reduced by 20 – 30 %, which translates into savings of several hundred PLN for a medium size house during the heating season. The EU Directive No. 2002/91/EC dated December 16th, 2002  on the energetic characteristics of the buildings, imposing the duty to obtain energy certificates for the newly erected and already existing buildings, emphasises the great importance, which is presently placed on the thermal insulation of all elements of the building, including the window joinery. Designing the FORIS pvc windows and doors, it is possible to fully use the construction possibilities of the system without the slightest concern for the thermal insulation of these elements.

Amount of heat that “escapes” through windows is defined by the U-factor (coefficient of heat transmission through windows). There is a general rule that the lower the U factor, the better the thermal insulating properties of windows. When a three-chamber FORIS 100 system is used the U-factor for window profiles is U= 1,6 W/(m2xK) whereas the five-chamber FORIS 500 system makes it possible to reach the U-factor value as low as Uf = 1,2 W/(m2xK). In combination with excellent thermal insulation of glazing panels where the corresponding U factor is Ug = 1,0 W/(m2xK) savings on heating costs can reach even up to 60%.