Uw values for wood folding sliding doors

The U_w values given below refer to the sample size. The sample size refers to a sliding door with a width of 3500mm and a height of 2180mm. All U_w values from German manufacturers are determined using this sliding door size. As the sliding door gets smaller, the U_w value goes down accordingly. For larger sliding doors, the U_w value is generally better.

Classic IV 68

Uw values Profile Classic IV 68

Spruce wood

Glass U_g value W/(m²k)	Frame U_f value W/(m²k)	Window U_w value insulating glass edge seal aluminium W/(m²k)	Window U_w value insulating glass edge seal uPVC W/(m²k)
1.1	1.1	1.3	1.3
1.0	1.1	1.3	1.2
0.7	1.1	Not possible for this system.	Not possible for this system.
0.6	1.1	Not possible for this system.	Not possible for this system.

Table of Uw values for Classic IV 68 profiles in spruce wood according to DIN EN ISO 10077-1, see comments 1) 2) 3) 4)

Wood types pine, larch, meranti

Glass U_g value W/(m²k)	Frame U_f value W/(m²k)	Window U_w value insulating glass edge seal aluminium W/(m²k)	Window U_w value insulating glass edge seal uPVC W/(m²k)
1.1	1.2	1.4	1.3
1.0	1.2	1.3	1.2
0.7	1.2	Not possible for this system.	Not possible for this system.
0.6	1.2	Not possible for this system.	Not possible for this system.

Table of Uw values for Classic IV 68 profiles in wood types pine, larch and Meranti according to DIN EN ISO 10077-1, see comments 1) 2) 3) 4)

Wood types oak, eucalyptus

Glass U_g value W/(m²k)	Frame U_f value W/(m²k)	Window U_w value insulating glass edge seal aluminium W/(m²k)	Window U_w value insulating glass edge seal uPVC W/(m²k)
1.1	1.5	1.5	1.4
1.0	1.5	1.4	1.3
0.7	1.5	Not possible for this system.	Not possible for this system.
0.6	1.5	Not possible for this system.	Not possible for this system.

Table of Uw values for Classic IV 68 profiles in wood type oak, eucalyptus according to DIN EN ISO 10077-1, see comments 1) 2) 3) 4)

Classic IV 68 - profile section

Classic IV 78

Uw values Profile Classic IV 78

Spruce wood

Glass U_g value W/(m²k)	Frame U_f value W/(m²k)	Window U_w value insulating glass edge seal aluminium W/(m²k)	Window U_w value insulating glass edge seal uPVC W/(m²k)
1.1	1.1	1.3	1.2
1.0	1.1	1.2	1.1
0.7	1.1	1.0	0.9 (0.93)
0.6	1.1	1.0 (0.95)	0.9 (0.87)

Table of Uw values for Classic IV 78 profiles in spruce wood according to DIN EN ISO 10077-1, see comments 1) 2) 3) 4)

Wood types pine, larch, meranti

Glass U_g value W/(m²k)	Frame U_f value W/(m²k)	Window U_w value insulating glass edge seal aluminium W/(m²k)	Window U_w value insulating glass edge seal uPVC W/(m²k)
1.1	1.2	1.3	1.2
1.0	1.2	1.2	1.2
0.7	1.2	1.1	1.0 (0.97)
0.6	1.2	1.0 (0.99)	0.9 (0.91)

Table of Uw values for Classic VI 78 profiles in wood types pine, larch and Meranti according to DIN EN ISO 10077-1, see comments 1) 2) 3) 4)

Wood types oak, eucalyptus

Glass U_g value W/(m²k)	Frame U_f value W/(m²k)	Window U_w value insulating glass edge seal aluminium W/(m²k)	Window U_w value insulating glass edge seal uPVC W/(m²k)
1.1	1.5	1.4	1.3
1.0	1.5	1.3	1.2
0.7	1.5	1.2	1.1
0.6	1.5	1.1	1.0

Table of Uw values for Classic IV 78 profiles in wood type oak, eucalyptus according to DIN EN ISO 10077-1, see comments 1) 2) 3) 4)

Classic IV 78 - profile section

Reference size 3500 x 2180mm
According to DIN EN ISO ₁₀₀₇₇, Uw values < 1.0 W/m²K are shown with 2 decimal points.
U_f = 1.3 (W/m2K) average
The U_w values given in brackets are not rounded and are for information purposes only.

In the case of a wood folding sliding door, the Uw values are calculated from the individual _Uvalues of the window frame and glazing, as well as the heat loss at the edge of the glass. For the sake of comparison, a standard window size of 1230 x 1480 mm is usually used for the calculation, but it can generally be assumed that a larger window will result in a lower value.

A thermally separated edge seal along the insulating glass - the so-called "warm edge" - further improves the thermal insulation of the entire door.

The heat transfer coefficients of a wood folding sliding door determine whether the door can be classified as suitable for passive houses, and also whether it will be possible to obtain funding from KfW banking group. Energy savings not only protect the environment, they also make an immediate difference on your energy bill.

The difference between a _Uw value of 3.5 and a value of 0.83 can make a difference of more than 1000 litres of heating oil per year for an area of 30 m².