Routing a Midea PortaSplit Through a Skylight: Brackets and Sealing Techniques

Routing a portable split air conditioner through a skylight — the scenario faced by loft conversion occupants and top-floor studio tenants across northern Europe — is technically more demanding than a standard vertical wall pass-through. The glass is angled (typically 15–65° from horizontal for most European roof window products), the frame construction combines glass, aluminium, and timber in a composite assembly, and the pass-through must accommodate both the refrigerant hose bundle and the condensate line while remaining waterproof under rain driving up-slope against the seal. The Midea PortaSplit skylight bracket solutions discussed here address each of these challenges systematically.

What makes skylight pass-throughs harder than wall installations?

A vertical wall sleeve only needs to resist gravity and horizontal rain loading — both forces that foam-sealed sleeves handle reliably. A skylight pass-through faces three additional challenges: angled rainwater runoff must not be channelled into the sleeve opening; the glass-to-frame junction has less thermal mass than masonry, so the sleeve is exposed to greater temperature cycling and the associated expansion and contraction stresses; and the Velux-style or Fakro-style roof window frame is typically not drillable at its centre — brackets must attach to the frame perimeter or the adjacent roof structure rather than through the glazing unit itself.

For this reason, the standard approach for a portable split skylight installation is not to drill through the glazing at all, but to route the hose bundle through a dedicated bracket assembly that fits into the gap created when the skylight is partially open, using a weatherproof saddle seal or foam-block closure to fill the remaining gap around the hose bundle. This approach requires no drilling, no structural modification to the window unit, and is fully reversible — critical for rental properties.

Which bracket types work for angled skylight installations?

Three bracket categories are available for routing portable split hoses through roof windows. The first is the foam-block slot kit: a pair of custom-cut high-density polyethylene foam blocks shaped to fit the open-skylight gap on either side of the hose bundle, compressing to fill the opening and creating a weatherproof seal through foam contact pressure. These are the simplest option, requiring no tools, but they are effective only for low-slope windows (up to approximately 35°) where gravity does not pull the foam blocks down and away from the frame seal.

The second category is the rigid saddle bracket: an aluminium or ABS extrusion shaped to straddle the open skylight frame, with a pre-drilled hose pass-through port and a weather-strip foam gasket on the frame-contact surfaces. Saddle brackets designed specifically for roof window brands (Velux GGL/GGU series, Fakro FTP-V U3/U4, Roto WDF, OKPOL IGV) are sold by specialist portable AC accessory suppliers in Germany, Austria, and the Netherlands, typically in the €35–€65 price range. These provide a superior weatherproof seal and hold the hose bundle at the correct angle to prevent kinking.

The third category is the custom fabricated panel: a rigid PETG or polycarbonate sheet cut to the exact aperture dimensions of the fully opened skylight, with a hole-saw cut for the hose bundle and a foam gasket bonded around the perimeter. This approach delivers the best seal quality but requires accurate measurement of the opened window aperture and either workshop access or a cut-to-order service. For permanent seasonal installations in owned properties, a custom panel is the most reliable long-term solution.

How do you size a skylight bracket for the Midea PortaSplit hose bundle?

The Midea PortaSplit quick-connect hose bundle — containing the liquid refrigerant line, the suction refrigerant line, the power cable, and optionally a condensate drain hose — has an outer diameter of approximately 65–75 mm when the constituent lines are gathered and wrapped in the protective sleeve. The bracket's hose pass-through aperture should therefore be 80–90 mm internal diameter to allow passage of the bundle with a thin foam wrap and to accommodate the quick-connect couplings, which are larger in diameter than the hose itself.

The saddle bracket's frame contact footprint — the width and depth of the area bearing on the roof window frame — must match the frame profile of the specific skylight model. Measure the internal opening width of the frame reveal at the point where the bracket will sit, and confirm the frame depth (front-to-back dimension) against the bracket saddle dimension before purchase. Frame dimensions vary between Velux GGL (centre-pivot opening) and GGU (top-pivot opening) series, and between the 78 mm and 140 mm installation-depth variants of the same model. Most bracket suppliers maintain a compatibility table on their product pages.

How do you manage condensation risk on a skylight pass-through?

Condensation on the cold refrigerant lines is the primary maintenance issue specific to skylight installations. As the suction line (carrying cold low-pressure refrigerant from the evaporator to the outdoor compressor) passes through the warm bracket zone, any gap in the insulation covering the line allows atmospheric moisture to condense on the cold surface. In a horizontal wall pass-through, condensate drips downward and dries harmlessly. In an angled skylight bracket, condensate can wick along the hose sleeve and track inward to the interior of the roof space or onto the window frame, potentially causing water damage to timber framing or triggering mould growth on permeable frame surfaces.

The solution is to maintain continuous closed-cell foam insulation (Armaflex-type self-adhesive pipe insulation, with a minimum thermal resistance of R-0.5 m²K/W) over the full length of the suction line from the indoor unit connection to the outdoor unit connection, with particular care at the bracket interface where the insulation is most likely to be crimped or torn. Seal any joints in the insulation with closed-cell foam tape rather than open-cell foam or standard gaffer tape, both of which absorb moisture and accelerate the formation of the condensation they are intended to prevent.

What are the hose length constraints for a skylight installation?

Skylight installations typically require longer hose runs than wall installations because the indoor unit is placed away from the roof slope (on a wall bracket or shelf in the loft room) and the outdoor unit sits on the roof deck or garden level some metres below. The standard Midea PortaSplit hose set is pre-charged to a fixed length of 1.5 m or 3.0 m depending on the product variant. Extended hose kits — available for some PortaSplit variants in 5 m and 7.5 m lengths — are required for skylight installations where the distance from the indoor head to the outdoor unit exceeds the standard hose length.

Extended hose sets should only be used if the manufacturer explicitly supports field extension, because adding length to a pre-charged refrigerant circuit changes the refrigerant charge distribution and can affect compressor efficiency and oil return. Check the specific PortaSplit model's installation manual for the maximum permitted hose length before purchasing an extension set. For installations requiring more than 7.5 m of hose run, a traditional fixed mini-split with professionally installed line sets is usually the more appropriate solution.

Spent a lot of time searching for how to get my PortaSplit through a Velux before finding the saddle bracket option. The foam blocks I tried first kept getting pushed out by wind — the saddle bracket has been solid through two summer seasons now.

Triple-glazed roof windows: when standard brackets do not fit

A growing proportion of European new-build and deep-retrofit loft conversions use triple-glazed roof windows — Velux Integra, Fakro FTP-V U5, and equivalent — with frame reveal depths of 140 mm or more compared with the 78 mm of standard double-glazed units. Standard saddle brackets designed for 78 mm frames do not bridge the deeper frame of these units correctly, leaving a gap that compromises the weather seal. For triple-glazed installations, measure the internal frame reveal depth carefully before ordering brackets, and contact the bracket supplier with the specific Velux or Fakro model number to confirm compatibility. Custom brackets for 140 mm frames are available from specialist suppliers but less commonly stocked, with lead times of 1–2 weeks — another reason to plan the installation before the heatwave season begins rather than during it.

Finding a PortaSplit unit ready for a skylight installation

Loft conversion and top-floor flat occupants are among the European residents most exposed to summer overheating — and the most motivated to find a portable split solution that works without a conventional wall penetration. Because PortaSplit-class units sell out rapidly during peak demand periods, a skylight installation plan that is ready to execute is worthless without a unit to connect to it.