Abstract: A gas filled panel (GFP) intended for general use, especially in construction, mostly in prefabricated building envelopes, i.e., integrated facades. A panel of the first embodiment is characterized in that it is a two- or more-chamber panel made of at least approximately plan parallel chambers with a mutual distance larger than or equal 8 mm, preferably between 8 and 12 mm, filled with insulation gas, which is a binary or ternary mixture of gases from hydro-fluorocarbons (HFC), carbon dioxide and argon and the mixture has an average molecular mass higher than 50 and lower than 71. A panel of the second embodiment is characterized in that it is a three- or more-chamber panel made of at least approximately plan parallel chambers with a mutual distance larger than or equal 18 mm, preferably between 18 and 22 mm, filled with insulation gas, or a mixture of gases having an average molecular mass higher than 38 and lower than 50.