They're beautiful. They flood the room with light. And they're a pain in the arse to open.
Velux windows are the single best thing about an attic conversion. They transform what would be a dark box into a bright, airy space with views of the sky. But there are practical things nobody mentions until you're living with them.
The standard Dublin setup
For a typical Dublin semi-d attic conversion, the standard configuration is:
2 large
Main living space
1 small
Ensuite (ventilation + light)
Most conversions will have two large windows for the bedroom or living area and a smaller one in the ensuite for ventilation and natural light. Some setups include an extra small window if there's a kitchenette or second room, but three rear-facing windows is the most common configuration.
All windows go to the rear of the house. This is important: rear-facing Velux windows in a standard attic conversion generally don't need planning permission. That changed for front-facing windows on 27 July 2026: CLASS 1C of the exempted development regulations now allows up to two roof lights on the front roof plane, neither exceeding 100 by 90 centimetres (1000 mm x 900 mm). A third, or a larger one, still needs permission - as does a dormer on the front roof plane.
Planning permission note
Rear-facing roof windows in a standard conversion are typically exempt under section 4(1)(h) of the Planning and Development Act 2000. Since 27 July 2026, up to two front-plane roof lights are also exempt under CLASS 1C, provided none exceeds 100 centimetres in length and 90 centimetres in width, and a dormer to the side or rear can be exempt under CLASS 1B within 30 cubic metres. Neither exemption applies in an Architectural Conservation Area where the works would materially affect its character. Check with your local planning authority if you're unsure.
Window sizes explained
Roof windows come in a range of standard sizes. The two most common sizes used in Dublin attic conversions are:
The narrower window, typically used for ensuite bathrooms where you need light and ventilation but space is limited. At 55cm wide, it's compact but lets in a good amount of light for a small bathroom.
Basis: manufacturers' published size charts, checked September 2026.
Check your quote
Some builders will spec smaller (cheaper) windows without telling you. Always ask: "What size are the roof windows in the quote, in centimetres?" The difference between a 55cm-wide and a 78cm-wide window in your main room is significant - don't let someone save €200 on a smaller window that you'll regret for years.
The reality of opening and closing them
This is the bit nobody tells you. Velux windows in a sloped ceiling are not like normal windows. You don't just reach out and push them open. They're above you, set into the slope, and depending on your furniture layout they can be genuinely awkward to reach.
Centre-pivot Velux windows have two positions: a ventilation position (cracked open a few centimetres at the top for airflow) and fully open (the window pivots on a central hinge so you can clean the outside glass from inside). The ventilation latch is at the top of the window - which is the highest point on the slope. The main handle is at the bottom of the window.
If you have a bed or a desk directly under the window, reaching that top latch means leaning across furniture. It's doable but it's not elegant. Velux supply a telescopic rod/wand for exactly this reason - do not lose it. It's the only comfortable way to open the ventilation position from below.
That awkwardness has a consequence worth naming. A ventilation latch nobody can reach is a latch nobody uses, and the plastered reveal around a rooflight is one of the coldest surfaces in the room and one of the first places condensation and black spotting show up. If that is already happening in your attic, our guide to condensation and mould in a converted attic covers what causes it and whose problem it is.
Think about furniture before fixing window positions
If your bed is going under the Velux, you’ll be reaching across it every time you want ventilation. Consider whether the window position and your furniture layout are compatible.
Keep the telescopic rod accessible
Velux supply a rod for reaching the top ventilation latch. Hang it on a hook near the window. If you lose it, you’ll be standing on the bed trying to reach the latch by hand.
Consider electric opening for hard-to-reach windows
Velux make electric and solar-powered opening versions. More expensive, but if a window is in a particularly awkward spot (above a built-in wardrobe, for example), the remote control is a genuine quality-of-life upgrade.
Blinds - electric vs manual
You will need blinds. An attic bedroom with south or west-facing Velux windows and no blinds is an oven in summer and a lighthouse at 5am in June. The question is what type.
We went with Velux electric blackout blinds and they've been one of the best decisions of the whole conversion. They pair together so you can open/close all blinds with one button press. They come with a wall-mounted, battery-powered switch (no wiring needed). There's also an app for phone control, though honestly the wall switch is all you need day-to-day.
The main advantage is practical: manually operating a blind on a skylight above your head - especially one you can barely reach - is annoying. Doing it twice a day (close at night, open in the morning) gets old fast. Electric blinds remove that friction completely.
Budget around €200-400 per window on top of the window cost, depending on size and blind type (blackout, duo, etc.).
Basis: published manufacturer specifications for roof-window blinds, checked September 2026.
Does the make of roof window matter?
Builders often substitute a cheaper roof window than the one you pictured, and the quote may simply say "roof windows" without saying which. That is not automatically a problem - but it is worth knowing before the windows are ordered rather than after.
What actually differs between makes is not the glass. It is how easily you can buy blinds, flashings and electric openers for that particular window in three years' time, when you want to add one. So ask which window is in the quote, then check that blinds and accessories for it are sold in Ireland before anyone orders anything.
What to ask your builder
"What size roof windows are included in the quote?"
Get the size in centimetres. Don’t accept ‘standard size’ — there’s a big difference between a 55cm and a 78cm window.
"What brand of roof window are you using?"
Blinds, flashings and electric openers have to be available for that particular window in three years’ time. Get the make in writing, then check accessories for it are sold in Ireland before the windows are ordered.
"Are blinds included in the price, or an extra?"
Blinds are often not included in the base quote. Clarify this upfront so you can budget for them. Electric blackout blinds add €200-400 per window.
"Can you position the windows so they’re reachable from the floor?"
The lower the window sits on the slope, the easier it is to reach the handle and ventilation latch. Discuss this before they cut the roof.
The bottom line
Velux windows make the room. They're the single biggest factor in whether your attic feels like a proper living space or a dark afterthought - and they directly affect your BER energy rating through their U-values. Go as big as your roof and budget allow. Get electric blinds if you can stretch to them - the daily convenience is worth it. And think carefully about where the windows sit relative to your furniture, because you'll be opening and closing them for years to come.
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