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How old is my VELUX window?

Updated: Dec 8, 2020

Replacing 250+ VELUX windows/skylights a year we are still surprised at the age of some windows that we replace that are still functioning as designed even if they no longer meet our ever increasing need for sound and heat insulation.

The chart below shows standard sizes of VELUX pitched roof windows along with there previous codes.

So looking at the CK01 at 550 x 700, CK01 being the current code used for this size you then have older generations including 9, 101 and C01.

Your window code will begin with either GGL, GHL, GPL, GGU or GPU, followed by numbers or a combination of letters and numbers.

If the GGL or similar is followed by 1 or 2 numbers you have a window manufactured before 1991.

If the GGL or similar is followed by 3 numbers you have a window manufactured between 1991 and 2001.

If the GGL or similar is followed by 1 letter and 2 numbers you have a window manufactured between 2001 and 2014.

If the GGL or similar is followed by 2 letters and 2 numbers you have a current generation VELUX window manufactured from 2014 onward.


Cant see your VELUX code above?

The codes above cover standard pitched roof VELUX windows, if you cannot see your code you may have another model type. Other models include vertical elements that are combined with a pitched roof VELUX, Balcony and Terrace VELUX windows or VELUX windows for uninhabited loft spaces. Contact us with a picture and the rough size of your window and we can normally help with obtaining the correct size code.


What does the GGL, GGU part of the code mean?

The first part of your code determines the operation and internal finish:

  • GGL - Centre Pivot Pine

  • GGU - Centre Pivot Upvc

  • GPL - Top Hung Pine

  • GPU - Top Hung Upvc

  • GHL - Top Hung Pine pre 2014

  • GHU - Top Hung Upvc pre 2014

  • FVL - Pre 1991 split pane window

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