VELUX codes

Old VELUX GGL and GGU Codes Explained

If your roof window has been in place for a while, the plate may read GGL 304 rather than GGU MK04. Here is what those older codes mean and how to turn one into a blind that fits.

What GGL, GGU, GPL and GPU denote

These four-character prefixes describe the window model, not the size. GGL and GGU are centre-pivot windows; GPL and GPU are top-hung. The prefix appears first on the identification plate, before the size code.

GGL — centre-pivot, lacquered pine
GGU — centre-pivot, white polyurethane
GPL — top-hung, lacquered pine
GPU — top-hung, white polyurethane

Pine versus polyurethane

The L and U endings tell you the finish. L models have a lacquered pine frame; U models are finished in white polyurethane, which is common in bathrooms and kitchens. The finish affects the look of the window, not the size of the glass.

Because of that, people often choose a white or light frame blind for a GGU and a warmer tone for a GGL — but both are ordered by size code.

How size codes relate across those models

VELUX uses the same size-code system across its centre-pivot and top-hung ranges, which is why you will see MK04 listed against several prefixes. VELUX documents the current size range itself — the link is in the primary sources below.

Our own compatibility data lists which prefixes each size code appears against, and that is what we order from. Where a prefix and size combination is not listed in our data, we do not assume it is equivalent.

If you are not certain, send us your full code or a photo of the identification plate and we will confirm the fit before you order.

Legacy numeric codes

Windows fitted before the modern coding system carry numeric codes. These are still very common in Irish homes and are fully covered — each has its own page listing the blinds that fit.

Single-letter M, S, P and C codes

Between the numeric era and today's two-letter codes, VELUX used single-letter size codes: M04, M06, M08, S06, P10, C02 and so on. These are the codes we see most often on Irish roof windows, and they are ordered exactly as printed.

Watch the difference between the single-letter and two-letter families: M04 and MK04 are different sizes, as are S06 and SK06.

Confirming your fit

Read the plate, note both the prefix and the size code, and open the matching size page to order. There is no need to measure the window — the printed code is what we make to. If the plate is unreadable, stop and send us a photo.

Because every blind is made to order, made-to-order blinds cannot normally be returned once produced; Bizzy Blinds may still authorise a return in certain circumstances — see our returns policy.

Common questions

What is the difference between GGL and GGU?

Both are centre-pivot VELUX roof windows. GGL has a lacquered pine frame; GGU is finished in white polyurethane. The prefix describes the window model and finish, not the glass size.

Does the same size code fit both a GGL and a GGU?

Where our compatibility data lists the same size code against both prefixes, yes. We check that list for every order rather than assuming an equivalence — send us your full code and we will confirm it.

My plate shows a number like 606 with no letters. What is that?

That is a legacy VELUX numeric size code from an earlier generation of roof windows. It is still supported and has its own size page listing the blinds that fit.

Is M04 the same as MK04?

No. They are different sizes from different generations of the VELUX coding system. Order exactly the code printed on your identification plate.

Primary sources

VELUX — roof window sizes — VELUX's published size range and size-code system.
VELUX — type sign (identification plate) — Where the type sign sits on a VELUX roof window and how to read it.

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VELUX® is a registered trademark of VKR Holding A/S. Bizzy Blinds is an independent supplier of aftermarket blinds compatible with VELUX roof windows and is not affiliated with VELUX.