Midea PortaSplit and French Windows: Installing Through Floor-to-Ceiling Glass
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French windows — the full-height glazed double doors that open onto a balcony, terrace, or garden in millions of European apartments and houses — are among the most common installation obstacles for portable split owners. The standard window kit supplied with a portable monoblock is designed for a sliding sash or hung window; it is completely unsuitable for a door that opens from floor to ceiling. The Midea PortaSplit, however, has no exhaust duct to route — only a pair of flexible refrigerant hoses that need a 60–70 mm combined gap to the outside, which opens up several practical solutions a monoblock exhaust hose cannot use.
What installation options exist for a portable split AC at French windows?
Three practical approaches suit a Midea PortaSplit at floor-to-ceiling French windows: a narrow gap panel inserted in the slightly-open door gap that seals around the refrigerant hoses, a free-standing outdoor unit frame placed outside the fully-open door with the hoses running across the door threshold, and a bracket mounting to the balcony railing or wall beside the door if any adjacent solid structure exists. Each has a different impact on door usability, thermal performance, and aesthetics.
| Solution | Door usability | Thermal seal quality | Hose routing | Reversibility | Best for |
|---|---|---|---|---|---|
| Narrow gap panel in door edge | Door held ajar 70–100 mm | Good — EPDM-sealed panel | Hoses pass through panel cutouts | Fully reversible | Inward-opening French doors, balconies |
| Full-height custom panel replacing one door | One door leaf blocked | Excellent — sealed rigid panel | Hoses through dedicated grommets | Reversible with panel storage | Ground-floor patios, landlord-approved |
| Free-standing outdoor frame, door fully open | Door must stay open during use | Poor without curtain/door seal | Hoses loop over threshold | Fully reversible; no fixings | Temporary use, good-weather sites |
| Balcony-railing bracket (hoses over railing) | Door left slightly open for hoses only | Good with draught strip at hose exit | Hoses over or through railing gap | Removable brackets | Balcony apartments, upper floors |
| Through adjacent solid wall | Door unaffected | Excellent — sealed core hole | Dedicated wall gland | Requires making good at end | Owned properties only |
How do you make a gap panel for French windows that seals properly?
A gap panel fills the narrow opening created by holding one French window door leaf ajar by 70–100 mm — just enough to pass the two refrigerant hoses through. The panel is cut from 25–40 mm rigid foam insulation board (Kingspan Kooltherm or equivalent, with a thermal conductivity of approximately 0.021 W/mK) to match the door gap dimensions: the full door height minus the threshold rebate at the bottom, and exactly the gap width. Two 40 mm holes cut with a hole saw accept the individual refrigerant hoses; EPDM foam strip seals the perimeter against the door frame and the door edge.
The panel's U-value (thermal transmittance — the rate of heat flow per square metre per degree of temperature difference, in W/m²K) is approximately 0.7–0.9 W/m²K for 30 mm Kooltherm, compared to approximately 1.0–1.4 W/m²K for a standard single-glazed French window pane. A well-fitted gap panel therefore introduces less heat gain per unit area than the glazing it replaces in the opening, rather than worsening it. The practical heat gain is further limited by the panel's small area — a 0.08 m² panel section at a 70 mm door gap in a 2.1-metre-tall door — which at a 10 °C outdoor-indoor differential adds only around 6 W to the room's heat load.
What is the best way to position the outdoor unit at a French window balcony?
For balcony apartments, the outdoor unit of the Midea PortaSplit sits on the balcony floor, kept 200–300 mm away from the balcony wall to allow unrestricted condenser airflow. The refrigerant hoses pass through the gap panel in the door opening or over the balcony railing lip through a 70 mm clearance, with a split-foam hose sleeve protecting the hoses at any point of contact with tile, railing, or window frame. The Midea PortaSplit outdoor unit weighs approximately 14–16 kg and its footprint of roughly 350 x 260 mm fits comfortably on a standard European apartment balcony without reducing usable space significantly.
On ground-floor patios with outward-opening French doors, the outdoor unit can sit on the patio immediately outside the door, and the hoses loop over the threshold through a low-profile draught-seal strip. A 10 mm closed-cell neoprene strip on the threshold compresses around the hoses to approximately 5 mm, creating a serviceable seal with a thermal resistance adequate for the small area involved. This is the simplest possible installation: no brackets, no panels, no drilling — just the unit on the ground, hoses over the threshold, door closed onto the neoprene seal.
The inward-opening vs outward-opening edge case: why door swing direction changes the entire approach
French windows in Northern European countries (UK, Belgium, the Netherlands) typically open inward; those in Southern Europe (France, Spain, Italy) more commonly open outward. This distinction is critical for panel design. With inward-opening doors, the gap panel sits on the outside face of the door aperture, held in place by the door pressed gently against it from inside — the EPDM seal and the door's own weight keep it in position without any fixings. With outward-opening doors, the panel must be held on the inside face, which requires a lightweight frame or compression clips because there is no door pushing it from outside. Getting this direction wrong before cutting the panel results in a panel that falls out of the opening rather than sitting in it.
How does leaving a French window ajar affect the PortaSplit's cooling efficiency?
A well-sealed gap panel held in the door opening has a negligible effect on the Midea PortaSplit's SEER (Seasonal Energy Efficiency Ratio — seasonal cooling output divided by seasonal electrical input, per EN 14825), because the unit does not create negative pressure or exhaust room air. The cooling penalty comes from any unclosed gap around the panel and hoses rather than from the hose routing itself. Independent thermal imaging studies of portable split installations show that a properly fitted foam-board gap panel with EPDM perimeter seal contributes less than 5% additional heat gain compared to a fully closed window in a typical European summer scenario.
By contrast, a portable monoblock routed through a French window — where the rigid exhaust hose requires the door to be held substantially open, often 200–300 mm — creates a large uncontrolled infiltration gap that can add 15–25% to the room's heat load, negating much of the compressor's work. The PortaSplit's slender 60–70 mm hose pair is intrinsically better suited to minimised door-gap installations than any monoblock exhaust duct.
In European apartment forums and home improvement discussions, PortaSplit owners with balcony French windows consistently describe the gap-panel approach as a revelation compared to their previous monoblock setup — the much smaller gap required for just the refrigerant hoses versus a full exhaust duct means the room actually seals well enough to hold temperature overnight, which was impossible with a monoblock and a forced-open patio door.
What materials do you need to build a French window gap panel?
- 25–40 mm rigid foam insulation board (Kingspan Kooltherm K10, Celotex GA4030, or equivalent) — cut to door-gap width by full door height, less the threshold rebate.
- 65 mm hole saw for the refrigerant hose cutouts — the twin hoses combined are typically 60–70 mm in overall cross-section; two separate 40 mm holes placed 80 mm apart centre-to-centre give individual routing clearance.
- Self-adhesive EPDM foam tape, 10–15 mm width, 4–6 mm uncompressed thickness — applied to all four panel edges to seal against door frame and door edge.
- Split-foam hose sleeve (pipe lagging), 35–40 mm internal diameter — wrapped around each hose at the panel exit point to protect the hose jacket from abrasion against the panel edge.
- Two small aluminium L-brackets (for outward-opening doors only) — screw-fixed to the door frame interior to hold the panel in position when the door is closed outward.
The complete materials cost for a French window gap panel is typically £20–45 depending on the insulation board specification. The panel takes 30–60 minutes to make and can be cut to size with a standard utility knife.