VELUX is the most widely stocked roof window brand in the UK, with the deepest spares support, the broadest size and accessory range and a premium price to match. Keylite sits mid-market and bundles the insulation and flashing components that others sell separately. Roto brings distinctive hardware and cleaning geometry. Fakro competes on price and offers some sizes and opening styles the others do not. None of these is simply best. The right brand depends on your budget, your roof, whether you need to match an existing window, and how important a dense local spares network is to you. Apex installs VELUX, Keylite and Roto, and we are not tied to any manufacturer, so the comparison below is the one we actually give at survey.
We are experienced installers of these products, not part of any manufacturer approval scheme, and that independence is the point. We have no reason to steer you toward one badge. What follows is how the four brands genuinely differ, and when an alternative to VELUX is the better call.
The four brands at a glance
This table is the factual comparison across the things that actually decide a specification. It is not a scoreboard. Each column matters more or less depending on your situation, which the sections below unpack.
| Brand | Size range | Spares availability | Glazing options | Price position | Notable strength |
|---|---|---|---|---|---|
| VELUX | Widest common range, most stocked sizes and the largest accessory ecosystem | Deepest and longest, current and recent generations well supported, dense merchant network | Double and triple, laminated inner pane, acoustic and solar-control options, integrated blind versions | Premium | Availability and spares depth, easiest to match and to service years later |
| Keylite | Broad range covering the common domestic sizes | Good through builders’ merchants, network less dense than VELUX | Double and triple, laminated options, thermal collar built into the unit | Mid-market | Insulation and flashing components bundled as standard rather than sold separately |
| Roto | Common domestic sizes, fewer niche options in UK stock | Available but thinner UK network, order-in rather than off-shelf in places | Double and triple, laminated, tile-and-slate flashing range | Mid to premium | Distinctive hardware and a pivot geometry that suits certain cleaning and comfort needs |
| Fakro | Wide range, including some larger and taller sizes and extra opening styles | Growing UK network, less dense than VELUX, spares improving | Double and triple, laminated, some high-pivot and preSelect opening designs | Value to mid-market | Price and size choice, and opening styles others do not offer |
Positions are relative and reflect the UK market as we see it across Suffolk and north Essex. All four make sound windows. The differences that matter are availability, matching and specification, not build quality in the abstract.
Availability and why it matters most
For a roof window, availability is not just about how fast you can buy one. It is about whether you can match, service and re-blind it years later. VELUX earns its market position here more than anywhere. It is stocked in depth across builders’ merchants in Ipswich and the surrounding towns, so a standard size is usually on a shelf rather than on order. That matters when a leak or a blown unit needs sorting before the next spell of weather.
Keylite is well carried through the merchant trade and is easy enough to source for a planned job. Roto and Fakro are both available, but in places they are order-in items rather than off-shelf, which adds a few days to a lead time. On a planned replacement that is irrelevant. On an urgent one it can matter. We tell you at survey what is genuinely on a shelf and what carries a lead time, because the brand that is quickest to obtain is sometimes the right answer on its own.
Spares and the long view
A roof window is in the roof for two or three decades, and the question that decides its later life is whether spares exist when something wears. This is VELUX’s clearest advantage. Its current and recent generations are supported for a long time, and because so many are in UK roofs, the hardware, gaskets and sealed units for them stay obtainable. That is precisely why matching an existing VELUX with another VELUX is usually the low-risk choice, covered on our roof window replacement page.
The others support their current ranges well. The difference shows further back in time. A ten-year-old Fakro or Roto unit can be harder to find parts for than a VELUX of the same age, simply because fewer were sold, so fewer parts move through the supply chain. None of this means the alternatives are a poor choice on a new fit. It means that when you are matching or planning to service in fifteen years, spares depth deserves weight in the decision.
Spares depth is not the same as build quality. A Fakro or Roto window fitted well today will serve as long as a VELUX fitted well today. The spares argument is about the long tail: how easy it is to find a part for a specific old unit. On any brand, though, once a window is old enough to need parts, the timber and flashing are usually old too, and replacement beats a parts chase. We do not offer parts work or resealing on roof windows for exactly that reason.
Size range and matching
All four cover the common domestic sizes, and the letter-and-number size logic is broadly shared, so an MK06 opening is an MK06 opening whichever badge fits it. Where they part company is at the edges of the range. VELUX has the most stocked standard sizes and the largest accessory family around them. Fakro offers some larger and taller units and a couple of opening styles the others do not, which occasionally makes it the right answer for an unusual opening or a specific comfort requirement. If you want the size logic itself, the size codes page sets out how the letter and number map to millimetres, and it applies across brands.
One practical point on matching. If you are replacing one window in a run of several visible from the street, matching the existing brand and generation keeps the external appearance consistent. The frame depth and the flashing profile differ between makes, and on a terrace those small differences read from the pavement. Where the windows are on a private rear slope, this matters far less and the decision can be made purely on specification and price.
Glazing options across the brands
Glazing is more alike than different across the four. All offer double and triple glazing, a laminated inner pane for safety, and low-emissivity coatings with argon fill as standard on current units. The choices that actually move performance are the same whoever makes the frame.
- Double versus triple. Triple glazing lifts the thermal performance and cuts noise, at a weight and cost penalty. It earns its place on a north-facing slope in a room you heat hard. On a small landing window it is often not worth it, on any brand.
- Laminated inner pane. Standard on current units and worth insisting on for anything over a bed, a stair or a bathroom, because a laminated pane holds together if it breaks.
- Acoustic and solar-control options. VELUX has the widest catalogue here, with dedicated acoustic and heat-reduction glazing. The others cover the mainstream need. If you are under a flight path or a busy road, the breadth of the acoustic option can tip the choice.
- Finish for humid rooms. A white painted or polyurethane finish rather than bare pine is the right call in any bathroom or humid room, and all four brands offer it.
Price positioning, honestly
Price follows the pattern you would expect. VELUX sits at the premium end and you pay something for the availability and the spares depth. Keylite and Roto occupy the middle, with Keylite’s bundled collar and flashing narrowing the gap once you count the components a VELUX quote lists separately. Fakro is the value option and genuinely competitive on the unit price, which is why it appears often where budget leads and the roof is a private slope with no matching requirement.
A word on comparing quotes across brands. The unit is a small part of the installed cost. Access, the flashing kit, both collars, labour and reinstatement dominate the total, and those are broadly brand-independent. Swapping a premium unit for a value one saves a couple of hundred pounds on a job that runs to well over a thousand. The installation cost page breaks the whole figure down, and it shows why the brand of the window rarely makes or breaks the price.
When an alternative to VELUX is the better specification
There are real situations where we would recommend something other than VELUX, and we say so.
- Budget leads and the roof is a private slope. If the windows are not visible from the street and there is no existing brand to match, a Fakro or Keylite unit gives you the same daylight and a sound install for less. The saving is real and the compromise is small.
- You want the collar and flashing bundled. Keylite builds the insulation collar into the unit, so on a specification-conscious job it removes one of the components that gets dropped from cheap quotes elsewhere. That has value beyond the pounds.
- An unusual size or opening style. Fakro’s wider size range and extra opening designs occasionally suit an opening or a comfort need that the standard VELUX range does not cover as neatly.
- You are matching an existing non-VELUX roof. If a run of windows is already Keylite or Roto and visible together, matching the existing brand keeps the appearance consistent and the flashing profiles alike.
And the honest reverse. If you are replacing a single VELUX in a visible run, if spares depth over the next twenty years matters to you, or if you want the widest acoustic and solar-control glazing catalogue, VELUX is usually the right answer, and its price reflects that. For the direct head-to-head that people ask about most, the VELUX versus Fakro page goes deeper on that specific pairing. For a period property, the conservation window comparison covers the recessed and heritage options across brands.
Blinds are brand-specific too
One thing the brand choice locks in is your blind supply. Blinds are made to the frame profile, so a VELUX blind will not fit a Fakro window and the reverse holds, even at the same size code. If keeping or reusing blinds matters, it points you toward matching the existing brand and generation. The compatibility detail is on our blind compatibility page, and it is worth reading before you switch brands on a room that already has good blackout blinds.
Common questions about brands
Do you only fit VELUX?
No. We install VELUX, Keylite and Roto, and we are not part of any manufacturer approval scheme, so we have no reason to push one brand over another. We recommend the brand that fits your budget, your roof and any matching requirement. On a visible run we usually match what is there. On a private slope led by budget, a value brand often makes sense.
Is VELUX actually better, or just better known?
Both, in a specific sense. All four brands make sound windows, so the build quality argument is largely even on a new fit. What VELUX genuinely leads on is availability and spares depth, because so many are in UK roofs that stock and parts move freely. That makes it the low-risk choice for matching and for long-term serviceability, and it is why it costs more.
Can I mix brands on the same roof?
You can, but think about sight lines. Frame depth and flashing profile differ between makes, so two brands side by side on a slope visible from the street will read as slightly different. On a private rear slope it does not matter and you can choose each window purely on specification. Blinds will not carry across brands, so a mixed roof means separate blind sizing.
Which brand is cheapest to install?
The unit is a small part of the installed cost, so the brand rarely swings the total much. Access, the flashing kit, both collars and labour dominate the figure and are broadly brand-independent. A value unit like Fakro saves a couple of hundred pounds on a job that runs well over a thousand. The full breakdown is on the installation cost page.
Get a fixed price for the right window
Tell us what you have, what you are matching if anything, and what matters most to you, budget, appearance, glazing or spares. We survey the roof, recommend the brand and specification that fits, and give you one written price with the U-value stated on it. We install VELUX, Keylite and Roto, we hold no manufacturer badge, and the recommendation you get is the one we would make for our own roof.
Every installation carries a 10-year workmanship guarantee, and the installers doing the work have 25 years fitting roof windows behind them. Request a fixed quote, or start from the main roof window installation page to see how the whole job is done.
Thinking about this job? We survey across Ipswich, Suffolk and north Essex and give you a fixed price before any work starts, with a 10-year workmanship guarantee.