The thermal insulation of frames (Uf thermal transmittance coefficient or thermal conductivity coefficient) is measured in W/m2K, and essentially this number defines the amount of heat (in Watts), per unit of time, that can pass through an aluminum profile with a surface area of 1m2, when the temperature difference between its two surfaces (inside – outside) is 1 degree (1 °C).
An aluminum frame, however, does not consist only of the aluminum profile, but also of the glass (glazing). These two materials, glazing and aluminum profile, have different coefficients (different thermal insulation – thermal transmittance). The thermal transmittance coefficient of the aluminum profile is called Uf (U Frame) and the coefficient of the glazing is Ug (U Glass). However, what truly helps us understand the overall thermal insulation of the frame is the Uw coefficient (U window), which refers to the entire frame, precisely because the glazing and the frame profile occupy a different surface area each time, depending on the dimension of the frame (bathroom window, balcony door, etc.).
See the Uf thermal transmittance coefficient in all thermally broken frames
