Best insulated side panels for window air conditioners
Researched by Deal.ai's shopping agent across stores on November 10, 2026. Prices below are today's.
Top pick: Breeze Stop Surround Insulation Side Panels. It's the one that seals the whole gap, not just the two side strips: a 1-inch foam core wrapped in white vinyl, cut to fit windows up to 36 inches wide, and it covers the top gap too. That's where most of the cold air and street noise leaks in.
Who the others suit:
- Breeze Stop 3-piece kit — same idea, slightly different sizing; good if your window is right at the 36-inch limit.
- Duck Brand foam panels (2-pack) — pre-cut 18 x 9 inch blocks; the simplest fix if your AC's own side panels are fine and you just want to back them with foam.
- Frost King urethane foam panels — a sturdier, denser foam for people who want a firmer panel that holds its shape.
- Full-surround foam kit (up to 39 inches, 5,000–22,000 BTU) — for wide windows or bigger units where standard panels don't reach.
- Arctic King and SZZSAF kits — budget-friendly spares or replacements when you only need the side pieces.
Two things to check before buying: measure your window's width and your AC's side-panel height, and pick foam over plain vinyl if noise is as much a concern as heat.
