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An inward-opening window asks something different of a project than a sliding unit. The sash occupies room space when open, the handle needs a clear approach, and the screen must remain usable after the reveals and interior finishes are complete. For an apartment package or a hospitality refurbishment, those relationships should be settled before the purchasing team compares unit prices.

The Y1 105 and Y3 110 series both belong on a shortlist for this type of opening, but the same external dimensions do not make them interchangeable. Their published construction details give a useful starting point. A meaningful comparison then connects those details to a room layout, an opening schedule and a clearly defined supply scope.

Begin with the room, not the series number

Draw the sash in its fully open position on the room plan. Add the finished wall return, curtain track, nearby furniture and anything fixed below the window. A drawing that shows only the frame rectangle cannot answer whether housekeeping staff can open the sash comfortably or whether a bedside table blocks the handle. Repeat this check for each room type rather than assuming one arrangement works throughout the building.

Separate everyday ventilation from the occasional full opening used for access or cleaning. Tilt operation and full inward rotation have different space requirements. Put the intended function against each opening in the schedule, then request a matching hardware arrangement. Where a restricted opening is required, have the designer specify the required restriction and ask the supplier to identify the compatible hardware.

What the Y1 105 brings to the comparison

The Series Y1 105 inward-opening window with screen lists multiple opening arrangements, including tilt-and-turn, together with a 1.8 mm wall-thickness design. Its construction description also identifies glue injection at 45-degree joints and mullions, inner and outer compression seals, and a drainage arrangement. These are useful discussion points for a fabricator's section drawing and assembly proposal.

Ask that proposal to identify which frame and sash sections carry the stated thickness, where seals meet at corners, and how drainage exits relate to the external sill. The drainage route should remain visible in the detail after the frame is installed. This helps the installation contractor coordinate sealant and finishes without accidentally treating a drainage opening as a gap to close.

Y1 is therefore a practical starting point where the brief centres on a screened inward-opening arrangement and a clear interface with the room. It still needs an opening-specific drawing. A series name alone does not establish the available clear opening, the screen's removal method or the reach required to operate the handle.

When to examine Y3 110 more closely

The Series Y3 110 inward-opening window with screen describes a 2.0 mm frame wall thickness, multi-chamber insulation strips, integrated sealing and a three-seal arrangement. It also lists micro-ventilation and a three-in-one glass railing function. Those additional interfaces deserve attention where the architectural brief combines ventilation, glazing and an integrated barrier concept.

For the glass railing option, request a drawing that distinguishes the operable sash, screen and barrier components. Identify who designs the barrier fixing and what project-specific evidence will accompany it. The phrase describes an available product function; the procurement decision should be based on the proposed assembly and its connection to the building.

The Y3 description also uses the glazing term 27A. Ask the supplier to expand that into the actual glass build-up offered: pane thicknesses, cavity, coatings and any relevant glass treatment. Carry the agreed build-up into both the quotation and the drawing. This avoids comparing one supplier's shorthand with another supplier's fully described glazing package.

Make the two quotations answer the same brief

Issue one schedule covering quantities, finished opening dimensions, handing, finish, screen requirements and the intended operating modes. Request separate pricing for any optional hardware or integrated barrier arrangement. If one quotation includes a screen or special fitting and the other excludes it, the apparent price difference is not yet a useful purchasing comparison.

Keep performance evidence tied to the offered configuration. Ask for the relevant test information for the frame, glass, size and hardware proposed for the project. Also agree the installation scope, packaging identification and replacement-parts information. A repeat room package benefits from clear opening references on drawings and delivery labels, especially when visually similar windows have different handing.

Use one representative opening to settle the details

Before releasing the full package, review a representative opening with the designer, supplier and installer. Work through handle access, sash movement, screen access, internal clearance and the sill detail in order. Record the agreed choices on the drawing revision used for purchasing. The strongest choice between Y1 and Y3 is the one whose complete arrangement fits the project and can be repeated consistently on site.