Both of these are old design ideas wearing modern aluminium. What’s changed isn’t the concept, it’s how slim and how large you can build them now.
A client renovating an old bungalow-style home near Kalyani Nagar came to us wanting to “bring back” the French windows her grandmother’s house used to have, the kind with tall glass panels opening fully into the garden. What she actually got looked nothing like her grandmother’s version, slimmer aluminium sightlines, better seals, far larger glass panels, but the spirit of the design, that full-width opening onto the outdoors, was exactly what she remembered. That’s roughly the story with both French and bay windows in aluminium right now. Old ideas, genuinely upgraded execution.
French Windows, Properly Explained
A French window is really a pair of tall, narrow glazed doors, hinged on either side, that open fully inward or outward to essentially remove an entire wall section between an interior room and whatever’s outside it, a garden, a balcony, a terrace. Unlike a sliding door, both panels swing open completely, so you get the full opening width rather than losing half of it to an overlapping fixed panel.
In aluminium, this design benefits enormously from slim, strong profiles. Because aluminium doesn’t need the bulk that wood or older steel systems required for structural strength, French window frames can run noticeably narrower now, which means more glass, less visible metal, and a cleaner sightline when both panels are open and the wall essentially disappears.
Why This Family Chose It Over a Sliding Door
The Kalyani Nagar client specifically wanted French windows rather than a large sliding door for her living room, and her reasoning was worth mentioning because it comes up with other clients too. A sliding door, however large, always keeps one panel in place, so you never get the full width of the opening genuinely clear. French windows, when both leaves are open, remove the entire boundary, which mattered to her for hosting, since she wanted guests to be able to walk through the full opening rather than around a fixed glass panel. It’s a genuinely different feeling standing in that room with both panels open compared to a slider pushed fully to one side.
Bay Windows, and Why Aluminium Changed What’s Possible
A bay window projects outward from the building’s main wall line, typically three panels angled to create a small alcove, a wider, more three-dimensional opening rather than a flat window set into the wall. It adds usable interior space, often just enough for a window seat or a reading nook, and it changes how light enters the room since you’re catching daylight from three directions instead of one flat plane.
Older bay windows, particularly in wood or heavier steel, needed substantial structural support for that projection, which limited how large or how slim the individual panels could realistically be. Aluminium’s strength-to-weight ratio changes that considerably, allowing larger glass panels within the bay structure and slimmer framing between them, so the whole feature reads as more glass and less visible construction than older versions of the same idea.
The Threshold Detail Nobody Asks About Until It’s a Problem
One thing worth raising before finalising a French window design, the threshold, the strip at floor level where the two panels meet the ground. A raised threshold seals better against water and wind but creates a small step or lip that can be a trip hazard or simply feel unwelcoming if the whole point of the design is a seamless walk-through connection to the garden. A flush, low-profile threshold looks cleaner and removes that step, but it demands more careful drainage detailing to avoid water pooling right at the opening during heavy rain.
We generally walk clients through this trade-off directly rather than defaulting to one option, since it genuinely depends on how exposed that opening is to driving rain and how much the client prioritises the flush, barrier-free look over pure weather performance. A north or east facing opening with some cover can usually get away with a lower threshold. A fully exposed south or west facing French window in a monsoon-heavy spot benefits from the slightly raised detail, even if it’s a small compromise on the seamless look.
Where Each One Actually Fits a Home
French windows work best wherever there’s a genuine connection to make, a garden, a terrace, a balcony worth walking out onto rather than just looking at through glass. They lose some of their appeal on an opening that doesn’t lead anywhere meaningful, since the whole point is that walk-through connection rather than just letting in light.
Bay windows suit rooms where you want to add a sense of space or a specific feature moment without extending the building’s actual footprint significantly, a living room, a breakfast nook, occasionally a bedroom where a window seat adds genuine usable space rather than just visual interest. They need a reasonably substantial exterior wall to project from, which rules them out for a lot of compact apartment layouts where there’s simply no wall depth or external space to work with.
What They Cost, Roughly, and Why
Both cost more than a standard window or sliding door of comparable size, for related but slightly different reasons. French windows need robust multi-point locking hardware on both leaves and precise alignment between the two panels to seal properly when closed, which adds to fabrication complexity. Bay windows need structural support for the projecting frame and typically involve more individual glass panels and angled joints than a flat window of the same overall width, which adds both material and labour cost.
On a recent quote for a bay window feature in a Baner project, the bay configuration ran somewhere around 30 to 35 percent more than an equivalent flat window opening of similar total glass area, largely due to the structural bracket work and the additional corner joints involved. That gap narrows somewhat on larger projects where the fabricator’s already mobilised for complex work elsewhere on the same job.
Quick Answers
Are French windows secure compared to sliding doors?
Yes, when fitted with proper multi-point locking on both leaves. Security comes down to hardware quality more than the door type itself.
Do bay windows need extra structural work during installation?
Generally yes, since the projecting frame needs support beyond what a flat window opening requires.
Can French windows be used on upper floors?
Yes, though wind exposure at height should factor into hardware and glass specification, similar to any large opening on a high floor.
Is a bay window practical for a small apartment?
Not usually. It needs external wall depth to project into, which most compact apartment layouts don’t have available.
Tell us which room you’re working with and whether it opens onto something worth walking into, and we’ll tell you honestly whether French or bay actually fits better than the other.
