Ask ten window buyers what the difference is between a side-press sliding window and a casement window, and nine will say the same thing: one slides, the other swings open. That answer is true, and it is useless for ordering. Both ALPES operable windows — the TS130 side press window and the C120, C113 and C116 outward-opening casement systems — ultimately win on the same thing: a compressed perimeter gasket. They arrive there by two different routes, and the route decides what the sash has to give up to get there, and what it costs you in the room. This article starts where that one-line answer ends.
"Slides versus swings" tells you how the sash moves. It tells you nothing about the three things a specifier actually pays for: how tight the seal is when the wind hits, how much of the wall opening you can use for air, and whether the sash needs a clear metre outside the wall. A side press window slides — but at the moment it closes, its hardware pulls the sash sideways into the frame and compresses the gasket, the same move a casement makes by swinging. So the honest first sentence is: the TS130 competes with a casement on sealing while keeping the sliding motion. The real difference is not the motion. It is what each design had to add, and what each had to leave behind, to reach that seal. When you read about a sliding casement window style, what you are really reading is the same argument from the other side: people keep blurring the line because the line really is blurry.
| Question | TS130 side press window | Casement (C120 / C113 / C116) |
|---|---|---|
| How the sash is held shut | Rollers carry it; side-pressure hardware pulls it laterally into the gasket on lock | Hinges carry it; multi-point lock draws it into the frame gasket |
| What it wins | No swing arc; full glass visible when closed; casement-level compression seal | Near-full opening; catches side breezes; wind pushes sash tighter |
| What it gives up | Only part of the width opens (about half two-panel, about two-thirds XOX) | Needs exterior clearance to swing; blocks walkways, decks, outdoor units |
| First thing to complain | Roller drag or track alignment — a movement problem, not a seal problem | Loose corner or worn gasket — an adjustment problem, rarely a part |
| Adjust or ｒｅｐｌａｃｅ | Rollers and side-pressure cam are adjustable; track is the fixed cost | Eccentric lock points and hinge geometry are adjustable with a key |
| Where the load lives | The track and the 200 kg-rated rollers, per sash, glass-dominated | The hinge, sized to sash width; 304 stainless on C116 |
| How much opens | Roughly half (two-panel) to roughly two-thirds (middle-fixed XOX) | Almost the entire sash, swinging clear of the opening |
| What you cannot remove | The horizontal track beside the opening | The swing arc outside the wall |
A casement sash is hinged on one side. When you turn the handle, a transmission box drives lock points that pull the sash against the frame, and a continuous gasket is squeezed all the way around. Wind pressure pushes the sash further into that gasket, so a storm makes it tighter, not looser. On the ALPES C120 this is a ROTO transmission box with anti-pry lock points; on the C113 it is CMECH hardware (a Red Dot design award line, tested to 30,000 cycles); on the C116 it is German Wehag hardware on 304 stainless high-load hinges.
The TS130 reaches the same result by a different path. It is a horizontal slider — but its side-pressure hardware, built around German ROTO side-pressure components, does not just latch the sash. When the handle returns to the locked position, the sash is drawn laterally into the frame and an eight-point locking system clamps it against a four-sided continuous sealing strip. Technical references on side-pressure lock blocks describe the same principle: the lock point contacts the frame first, then further handle travel produces a few millimetres of elastic compression on the gasket. That is why ALPES describes the TS130 seal as "casement-level" — not as a slogan, but as a description of the closed state.
A casement that leaks is usually an adjustment problem: an eccentric lock point that drifted, or hinge geometry that no longer pulls the corner square. You fix it with a key, not a parts catalogue. A side press slider that jams is a movement problem — a roller that has lost its glide or a track that has dropped out of alignment — not a gasket problem. Both can be adjusted, and both can be ruined by a installer who skips the first adjustment. The point is that the two windows fail in different places, so the person who services them needs to know which one they are standing in front of.
This is the part most brochures hide. The TS130 only reaches casement-level sealing when it is pushed shut and locked. A side press window that is slid closed but left unlocked is, mechanically, a slider with an expensive gasket sitting beside it. The same is true of a casement left ajar. So when a datasheet says "casement-level sealing," read it as "casement-level sealing when the hardware has done its job" — which is exactly why first-adjustment and periodic re-tension belong in the handover, not in the warranty small print.
Both windows are compression-sealed, so both sit at the top of the operable-window airtightness range — that is the direction, and it is safe to state. What you should not accept is a single printed number used to close the argument, because a thermal or airtightness figure belongs to a specific test specimen, not to a product name. Three questions separate a real answer from a brochure line:
ALPES publishes K-values for its outward casement systems (C120 at 1.6, C116 at 1.7, both in W/m²K) and for the AW90 tilt-and-turn passive window at 1.3. The TS130 sliding series does not publish a K-value, and that is the honest position: a sliding sash must keep a running gap to roll, so its thermal figure is project-specific. Ask for the value at your glass build-up rather than reading one off a different window.
A casement hangs from hinges sized to the sash width; the C116 uses 304 stainless high-load hinges with a built-in hardware groove. A side press slider rests on rollers — the TS130 uses 200 kg load-bearing pulleys, and that rating is per sash, not per window, and it is set by the glass. A useful rule of thumb from glazing practice: glass weighs about 2.5 kg per square metre for every millimetre of thickness, so a 24 mm insulated unit runs roughly 25 kg per square metre. A wide TS130 sash is therefore a heavy, glass-dominated panel, and the 200 kg roller rating exists precisely so that panel stays easy to move for years. Two consequences follow: the maximum sash size is published against an assumed glass thickness, and a heavier glass build lowers that maximum. ALPES does not print a single TS130 maximum sash dimension in its public catalogue — request it against your glass spec, do not assume it from a sibling sliding door.
Both windows keep the insect mesh on the room side. The casement carries a standard 40# black stainless mesh with an anti-PM2.5 high-definition option; the TS130 offers an extended inward-opening sash mesh so you can service the screen without reaching outside. On geometry, a casement opens almost the full sash and catches side breezes like a sail, but to get both a fixed view and a vent you add a mullion. The TS130 is built the other way round — one fixed plus one movable, or a middle-fixed two-sides-movable (XOX) layout — so a wide wall gets a fixed view and a vent with no extra mullion clutter, at the cost of opening only part of the width. For large sliding window openings this is the whole point: you keep the panorama and still get a controllable gap.
The space argument is the one that actually decides projects. A casement swings out, so anything in its arc — a walkway, a deck rail, a balcony, an outdoor unit, a planter — becomes a conflict, and on upper floors the swing is often restricted or prohibited. The TS130 needs no exterior clearance at all; what it needs instead is horizontal track room beside the opening, which is almost always easier to find than a clear swing arc. That is why side press sliders dominate balconies and high-rise elevations while casements dominate rooms where you want the sash to disappear and the breeze to come in at an angle.
Choose the TS130 side press window if you need a wide, mostly-fixed view with a vent that does not swing into a walkway or balcony; you want casement-level sealing without giving up the sliding motion; the elevation is high-rise or tight outside; and a heavier glass panel on 200 kg rollers is acceptable for the opening.
Choose a casement (C120 / C113 / C116) if the opening is tall and narrow; you want near-full ventilation and the ability to catch a side breeze; exterior clearance is free; and you would rather have a hinge-and-lock adjustment than a roller-and-track one. For a small sliding window sized opening where a casement would be oversized, the hinged sash often fits the wall better and vents more of it.
| Item | Published by ALPES | You must request it |
|---|---|---|
| Thermal K-value | C120 1.6, C116 1.7, AW90 1.3 (W/m²K) | TS130 sliding value, and any value at your glass build-up |
| Air / water / wind rating | Not published for these operable lines | Test report at your opening size and glass spec |
| Hardware cycle count | C113 CMECH 30,000 cycles (test-bench) | TS130 ROTO side-pressure bench count; cycle count is not service life |
| Roller / hinge load | TS130 200 kg rollers per sash | Max sash size at your glass weight |
| Corrosion test | 240 h salt spray (AW90 only) | Do not transfer AW90's figure to TS130 or casement |
| Ask | A good answer | A reply that sounds fine but says nothing |
|---|---|---|
| Thermal value at my glass | A figure tied to a named IGU and opening size | "Very efficient, passive-grade" |
| Test specimen configuration | The actual sliding or hinged sash, not a fixed unit | "Fully tested system" |
| Max sash size, TS130 | A dimension stated against an assumed glass thickness | "Up to very large" |
| Hardware brand and bench count | ROTO / CMECH / Wehag named, with cycle figure noted as bench | "German hardware" |
| Profile and break | 6060-T66, 1.8 to 2.0 mm, PA66GF25 multi-chamber | "Thermal break aluminium" |
| Sealing story | Four-sided continuous seal + eight-point lock (TS130) named | "Excellent sealing" |
| First adjustment included | Yes, at handover, with the procedure documented | "No adjustment needed" |
| Exterior clearance needed | Casement swing arc stated; TS130 stated as none | "Fits any wall" |
| Spare parts availability | Rollers, cams, gaskets listed as stockable | "All parts available" |
| Project submittal package | Drawings, test reports, and a named contact for the region | "We handle everything" |
No. It is a horizontal slider that reaches casement-level sealing through side-pressure hardware. It keeps the slider's no-swing-arc advantage, which a true casement cannot.
Both are compression-sealed and sit at the top of the operable range. ALPES publishes K-values for the casement lines and the AW90; the TS130 sliding value is project-specific, so compare at the same glass build-up rather than from memory.
Not fully. A two-panel opens roughly half the width; a middle-fixed XOX opens roughly two-thirds. That is the price of keeping the sliding motion and the fixed view together.
Usually the TS130, because it needs no exterior swing clearance. A casement swing is often restricted on upper floors for exactly that reason.
Both are adjustable. Casement issues show up as corner drift or gasket wear (adjust the lock points); TS130 issues show up as roller drag or track alignment (adjust the rollers and cam).
Yes — request it against your opening size and glass specification. Do not take a casement or tilt-and-turn figure and apply it to the sliding series.
The difference between a TS130 side press window and a casement is not "slides versus swings." It is that both reach a compressed perimeter seal, but the casement does it by swinging into the frame while the TS130 does it by sliding and then pressing sideways — and the TS130 keeps the no-swing-arc advantage that a casement gives up. Pick the casement when you want the sash to vanish and the breeze to come in at an angle; pick the TS130 when the wall outside is crowded, the opening is wide, and you want casement-level sealing without the swing. Either way, ask for the numbers at your own glass and opening, because a figure printed for a different specimen is not your window.
