Insulating glass
New insulating glass units for windows and doors – for thermal, sound, solar or burglary protection, made to measure and fitted by our team. Usually the frame stays.
Misted up between the panes?
Then the edge seal is leaking: the gas in the cavity escapes, moisture gets in, and the unit no longer insulates as before. We replace the insulating glass unit – the frame stays if it is in good condition.
Typical signs
- condensation or droplets between the panes that cannot be wiped away
- a milky haze in the glass
- a crack in one of the panes
How insulating glass is built
At least two panes with a sealed cavity in between. What the glass can do is decided in the layers.
Ug ≈ 1.1 W/(m²K)
Double glazing with coating and argon. Schematic, not to be used for dimensions.
Panes of glass
Two or three panes – depending on the protection, laminated glass or panes of different thickness.
Cavity
Usually filled with argon. How well it insulates depends on the gap.
Coating
A wafer-thin layer on one pane reflects heat radiation back into the room.
Spacer
A profile running round the edge keeps the panes apart. It is filled with desiccant.
Edge seal
Two sealing stages join panes and spacer and keep the cavity tight.
Warm edge
Aluminium spacers conduct heat outwards very well – the edge of the glass gets cold and condensation can form. Spacers made of materials that conduct far less can more than halve the heat loss at the edge.
Four tasks, four make-ups
Depending on the make-up, insulating glass keeps heat in, noise and sun out – or makes break-ins harder.
Thermal insulation
The sealed cavity insulates and is usually filled with argon. An ultra-thin coating on one pane reflects heat radiation back into the room.
The values behind them
- Thermal insulationUg valueW/(m²K)
- How much heat is lost through the glass. The lower, the better.
- Sound insulationRwdB
- Weighted sound reduction index. Under VDI 2719, windows fall into six sound insulation classes: class 1 from 25 dB, class 6 from 50 dB.
- Solar controlg value0 to 1
- The share of solar energy that passes through the glass into the room (DIN EN 410). 0.6 means 60 per cent.
- Burglary protectionResistance classDIN EN 356
- P1A to P5A resist thrown objects, P6B to P8B resist breaking through. The German police recommend glazing from P4A.
A new pane in an old frame: the rules
If you replace the glazing of a window in a residential building, the German Building Modernisation Act (formerly the Building Energy Act) requires glass with a Ug value of no more than 1.1 W/(m²K). There are exceptions:
- If the existing frame cannot take this glazing, the requirement does not apply.
- If the glass thickness is limited for technical reasons, a Ug value of no more than 1.3 is enough.
- For box and coupled windows, one pane with a low-emissivity coating (emissivity no more than 0.2) is enough.
The legal text (Annex 7) is what counts. We clarify what applies to your window when we measure up.
To the old Berlin box-type windowHow the pane replacement works
01
Measurement on site
We take the measurements and check the condition of the frame.
02
Transparent quote
You know in advance what the repair will cost.
03
Manufacture
Once you approve, we make the matching pane.
04
Installation
Our team installs it professionally – in many cases at short notice.
Misted-up pane?
We replace it.
Call or write to us. A photo of the pane helps us assess it.
Frequently asked questions
How can I tell that an insulating glass unit is faulty?
Typically there is condensation or moisture between the panes that cannot be wiped away. Then the edge seal is leaking: the gas escapes and moisture gets in. The unit is replaced.
Do I have to replace the whole window?
Usually not. We replace the insulating glass unit and the frame stays – provided it is in good condition. We check this during the free measurement.
What does the Ug value tell me?
How much heat is lost through the glazing, in W/(m²K). The lower, the better: double glazing with a coating and argon reaches about 1.1, triple glazing about 0.7.
What rules apply if only the glazing is replaced?
In residential buildings, the German Building Modernisation Act (formerly the Building Energy Act) requires a Ug value of no more than 1.1 W/(m²K). There are exceptions, for example if the existing frame cannot take this glass, and separate rules for box and coupled windows.
Will triple glazing fit my old frame?
That depends on the frame. Triple glazing is thicker and heavier than double glazing. We check whether your frame can take it when we measure up.
Does insulating glass help against noise?
Yes, with the right make-up: panes of different thickness and laminated glass with an acoustic interlayer. Tight joints at the frame matter too. How well a window insulates is shown by the sound reduction index Rw in decibels.
What does P4A mean?
A resistance class under DIN EN 356 for glass that resists thrown objects: in the test, a 4.11 kg steel ball is dropped onto the pane three times from a height of 9 m. The German police recommend glazing from P4A.