# What is the recommended value for the Uw coefficient of joinery?

For classic windows, coefficients must be between Uw ≤1.3 W/m²K and Sw ≥ 0.30 or Uw ≤ 1.7 W/m²K and Sw ≥ 0.36. For the roof windows, the forks between which they must be are of Uw ≤ 1.5 W/m²K and Sw ≥ 0.30 or Uw ≤ 1.7 W/m²K and Sw ≥ 0.36.

### How to calculate a transfer coefficient?

Transfer coefficient overall thermal The composition is calculated by adding the inverses of the different coefficients interface and transfer coefficients like the composition of electrical resistors in parallel (assuming the flow is unidirectional).

### How to calculate the UW value of a window?

This is the reason why today, we hardly use single glazing anymore in the manufacture of windows, but only for the interior, for furniture for example. For the calculation of the Uw value, the surface of the window, ie the glazing, must also be taken into account.

### What is the unit of measure for the value of a window?

The unit of measurement for the U-value is W/ (m 2 K). The lower the U-value, the more effective the thermal insulation. The better the windows are equipped, the more you save.

### How to calculate the coefficient of a window?

The U-value of a window disperses through different elements. The U-value for the entire window model is made up of the values ​​of all of these elements. This calculation can however be quite complicated as the glazing and frames vary in their materials and therefore in their insulation coefficients.

### How to calculate the result of a window?

In the case of a window, all construction elements and the spaces between them must be respected. The U calculator takes all these elements into account and will present the result to you with a simple click.