Find the Right Portable AC Window Insert for Your Window
Casement Window
Side-hinged windows that swing open and are difficult to seal properly with standard kits. This custom insert is cut to your exact opening, creating a tight seal so hot air vents outside efficiently instead of leaking back in.
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Awning/Basement Window
Top- or bottom-hinged windows that leave awkward gaps most standard kits can’t handle. This insert is built to fit your exact opening, allowing your AC to vent cleanly outside without leaks or patchwork fixes.
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Single/Double Hung Window
Up-and-down sliding windows where most panels shift, leak, or fall out of place. This custom insert creates a secure, precise fit so your AC vents efficiently without constant adjustments or air gaps.
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Sliding Window or Door
Wide sliding openings where most solutions leave gaps or block part of the view. This insert creates a clean, sealed vent while keeping the rest of your window or door usable and fully unobstructed.
Click HereWhy Homeowners Choose a Custom Window Vent Insert
Crystal-Clear Plexiglass
Our panels look like glass — clear enough to let natural light in while keeping hot air out. Far superior to wood, cardboard, or foam solutions that warp and deteriorate.
Custom Cut to Your Dimensions
Every insert is made to order for your exact window measurements. No more ill-fitting panels with drafty gaps — a precise snug fit every time.
Works With Any Portable AC
Compatible with all major portable air conditioner brands including Midea, LG, Whynter, Honeywell, and more. Universal hose connection points.
No Permanent Modifications
Install and remove easily without drilling, cutting, or damaging your window frame. Perfect for renters and homeowners alike.
Perfect Fit Guarantee
If your window insert doesn’t fit perfectly, we’ll remake it – free of charge.
Even if the measuring mistake was yours.
Email us at info@martinsonmanufacturing.com and tell us what needs adjusting. “Make the width ½ inch shorter.” “Tighten the height.” Whatever it takes. We’ll cut a new one and ship it the next business day.
We don’t leave customers stuck with something that doesn’t work.
Clear Shipping Times. No Guesswork.
Every insert is custom-cut and shipped with clear timelines. Choose the delivery speed that works for you, standard shipping is always included.
UPS Ground
Typically 3–5 business days once shipped. Included with every order.
2nd Day Air
Need it sooner? Upgrade to 2‑day delivery at checkout.
Overnight
Our fastest option. Delivered the next business day after shipment.
Canada Shipping
UPS Ground shipping to Canada. Import duties and taxes may apply at delivery.
Portable AC Window Venting Done Right
