In the pursuit of a more refined window AC installation — building in Midea U-Shape Inverter Splits
I’ll share the finished product first so you don’t have to waste your time reading my long winded ramblings — cables managed at this point, controlled via Honeywell ductless thermostats, connected to Brilliant Home for light switch HVAC control and Homebridge for HomeKit control!
My wife and I do own our home, which you would think is enough to choose whatever HVAC system your heart desires… but since it’s a 1920s landmark NYC building, installing a condenser for central air or mini-splits on the shared roof is about as easy as passing a new federal law. After a tremendous amount of obsessing, I landed on Midea U-Shaped inverter window ACs as a stopgap until we can secure the roof access needed for a proper standalone unit. They’re highly efficient for a window unit because of their mini-split design and DC inverter tech (15 SEER), quiet, and relatively inexpensive. Now, three years later, the stopgap may be the permanent solution — they’re really that good!
Before — the initial install using supplied insulation and some additional adhesive insulation cut to size. Control only via the units themselves/remote or the Midea app. Works great, but ugly and not particularly airtight.
I experimented with a few iterations using thinner paneling but eventually settled on 3/4" thick pine. Using a jigsaw, I cut the wood to the final size of 40" x 7", with a dip to 2" under the unit. I initially planned to embed neodymium magnets to hold it up, but the friction fit was more than enough, so I didn’t bother. The wood was cut to fit snugly, including grooves for the support brackets — made with a multi-tool for the 2" cuts (because I didn’t want to set the sawhorse back up 😄)
I added roughly 3" total of adhesive foam insulation between the exterior and the wood paneling, including heatproof aluminum-backed strips to prevent the foam from degrading over time. I also sealed the overlapping area resulting from the slightly open window. The insulation was cut into strips matching the width and length of the panel and layered five times using the following materials:
After layering the insulation and fitting the wood panel in place, I sealed the edges where it meets the AC unit and walls with Kwik Seal waterproof caulk. Once dried, I sanded everything using 400-grit finishing pads on the multi-tool.
For paint, I used the same color as our enclosures and window frames — Sherwin Williams Ultra White SW7006 — to match the surroundings. A foam roller was perfect for the main coverage, while small brushes handled the seams and edges. Then, I applied an additional weatherproofing layer on top. Now, it’s basically as insulated as our exterior walls, with the added bonus of essentially zero compressor noise.
Finishing Touches
We have two 12,000 BTU units and two 8,000 BTU units, all controlled by Honeywell D6 Pro thermostats. They’re integrated into Brilliant Home for switch-based control and Homebridge for HomeKit support. Everything works seamlessly via iOS now, which is lovely. Ultimately, I found little value in the wall controls and ended up using Homebridge directly to control the units so I could activate the dehumidifier function and control fan speed more effectively.
I’m thrilled with how the project turned out — both aesthetically and functionally — the improved insulation and noise reduction makes it worthwhile even without the good looks.
