What the three have in common
FAKRO, Keylite and VELUX are all manufacturers of roof windows, the hinged kind set into a pitched roof. If you are still working out what separates a roof window from a skylight or a rooflight, that comparison comes first.
Each maker sells a range of sizes, a choice of opening styles and a choice of glazing. Each supplies flashings designed for its own windows and for different roof coverings, from plain tiles to slate. Each also offers extras such as blinds, and some sell electric and rain-sensing versions.
For a householder, that is the useful starting point: they are in the same business, selling the same basic product. No maker has a monopoly on a working roof window, and none of them is better in every case, because it depends on the roof, the room and what you want from the window.
Where the makes actually differ
The differences are practical, and they sit in the product specifications rather than in the name. Compare these against the manufacturer's own literature:
- Sizes. Each maker has its own size range and its own way of coding the sizes. A window from one maker is not guaranteed to match an opening cut for another. VELUX writes its sizes as a code such as MK04, and our size codes guide explains the system.
- Opening style. Top-hung, centre-pivot and other action types are offered in different combinations by different makers. Your ceiling height and the handle position decide which will suit, not the logo.
- Glazing. Thermal, acoustic, solar control and safety glass options vary between ranges. Check the stated U-value against the Part L figure for roof windows.
- Flashings. Flashing kits are made to suit the maker's frame and the roof covering. The kit that comes with the window is the one designed for it.
- Controls and accessories. Electric opening, rain sensors and blinds are specified per range. If you want any of these, check they are offered for the size and type you need.
Ranges change over time, so the manufacturer's current catalogue is the place to confirm any of this, not a blog post. Ask for the data sheet of the exact model on your quote, and compare like with like: the same size, the same opening action and the same glazing build-up. A comparison across mismatched specifications tells you very little.
What matters more than the badge
Three things decide how a roof window performs in the years after it goes in, and none of them is the make.
The fit. The window has to be sized to the rafters and the covering. Rafters rarely fall where you would like, and a trimmed opening that follows them is stronger than one that forces a window into the wrong place.
The weathering. Water is the enemy. Flashings need to lap the tiles or slates properly, and the order of the layers around the frame is what keeps the room dry. A well-fitted window of any make beats a badly weathered one of any other.
The finish inside. The sloping reveal, the lining and the insulation around the frame decide how the window looks and how warm the room feels. A tidy lining makes a plain window look right.
That is where the hours go on a job, and it is why we spend the survey on the roof and the room rather than on the brand.
Replacing one make with another
People often ask whether they can swap an existing window for a different make. Sometimes yes, sometimes it needs the opening altered. Sizes differ between makers, so a like-for-like match is not guaranteed. If the new frame is slightly smaller, the gap can be filled and the flashings changed. If it is larger, the opening has to be widened or lengthened, which means cutting back the covering and perhaps trimming timber.
If you already have a window and like it, replacing it with the same make and size is usually the simplest route, because the opening is already the right shape. If you want a change, tell us the make and size on the label, ideally with a photograph of the frame, and we will say what the swap involves before you commit.
Whichever make you choose, for a replacement or a new window, ask for the product to be named on the written quote. That way you know what is going in, and the price covers that specific unit.
Choosing without chasing the brand
A sensible way to decide:
- Start with the room and what you want from the window: air, light, a view, a way of cleaning the glass.
- Check what fits the roof: the pitch, the covering, the rafter positions.
- Look at the specification: glazing U-value, opening action, and any controls you want.
- Then pick the make that ticks those boxes. If two do, the choice is yours.
Brand loyalty is a perfectly good reason to choose, and so is the one that your neighbour has and likes. It is just not a technical reason.
The window should also meet the regulations where they apply. Roof windows in existing homes are assessed against Part L, and the planning side is usually permitted development; the short version, and the exceptions, are in our planning and Building Regulations guide.
For the wider picture of types and sizes, see our roof windows page. Ready to go ahead? Ask for a free survey: we measure the roof, talk through the options and send one fixed written quote. The makers' names here describe products only.