It is important to consider the frames and glazing while designing and building a house, mostly for a high energy performance building.
Wooden window frames require less energy to manufacture than aluminium or PVC frames. On the other hand, they require some maintenance for the exterior as well as for the interior. More simply, it is possible to choose mixed windows, combining wood and aluminium.
Wooden windows have high thermal performance and provide a barrier to external noise.
Losses from glazing represent about 13% of total losses. It is therefore important to choose the right glazing.
For Portugal there is no need to install triple glazing (except in the case of renovation where large windows must be placed on the north elevation).
Double glazing filled with argon is the best option to reduce convection losses. It will be possible to choose a glazing with a special metal oxide coating on the inside to reduce heat losses by radiation by about 30%. We call it RTI (reinforced thermal insulation) or RIG (reinforced insulation glazing).
It is forbidden to use aluminium spacers (the part that separates the two panes of glass from a double glazing).