Do interior storm windows work?

Yes, they can reduce heat loss by 30-50% and dramatically reduce drafts and condensation on single-pane windows.

Can I still open my windows?

You must remove the interior panel to open the window. Magnetic and compression panels pop out easily.

Storm Window KitGenerating image…

Caulking & Weatherproofing

Window Insulation

Budget: $15-$30 (basic plastic sheet kit) | Mid-range: $30-$60 per window (acrylic panel with magnetic frame) | Premium: $80-$200 per window (custom track-mount acrylic)

Storm Window Kits: Interior Storm Windows for Draft Reduction (2026)

Prepared by Lumberama's Building Materials Team

|Last updated May 25, 2026|Sources & methodology

Storm window kits add an extra layer of insulation to existing windows by creating a sealed air gap. Interior storm windows mount inside the window frame using magnetic strips, compression seals, or track systems. They reduce drafts, condensation, and noise while improving energy efficiency without altering the exterior appearance.

Key Features

Interior mount preserves exterior look; Magnetic
compression
and track systems; Acrylic or polycarbonate panels; Reduces drafts and condensation; Removable for summer ventilation

Specifications

Panel: acrylic or polycarbonate

1/8" to 3/16" thick | Mounting: magnetic

compression

track | Custom sizes: cut to fit | R-value added: R-1.5 to R-2.5 | Noise reduction: 50-75% | UV filtering: varies

Applications

Drafty single-pane window insulation; Historic home window preservation; Rental property window upgrades; Noise reduction from outside; Condensation prevention on cold glass

Installation Overview

Measure window opening precisely. Cut panel to size (or order custom). Install magnetic strip or compression seal to window frame. Press panel into frame to create sealed air gap. Remove in spring for ventilation if desired.

Pros & Cons

Pros

✓ Dramatic draft reduction; Preserves historic window appearance; Reduces condensation and noise; Removable for summer

Cons

✗ Custom fitting can be fiddly; Must be removed for window operation; Acrylic panels can scratch; Upfront cost per window adds up

Top Brands

Indow

WindowSeal

Magnetite

Code Requirements

Interior storm windows must not impede emergency egress per IRC R310. Must be removable. Some historic preservation boards require interior-only storm windows to preserve exterior appearance.

Buying Tips

Magnetic-mount systems offer the best balance of performance and convenience; Measure each window individually as sizes vary; Indow brand offers premium custom-fit acrylic panels for historic homes and maximum performance