​ComfortSEAL Interior Windows

Interior windows mount inside your home to block drafts, reduce outside noise and increase energy efficiency.

  • Installs inside the home and fits almost any window.
  • Ultimate design features tilt-in window for easy access and cleaning. Patent pending.
  • Single-Hung is balanced for smooth operation.
  • High-performance Low-E glass makes your home more comfortable and reduces fading. All comfortSEAL windows available with Low-E glass.
  • Super easy installation in ten minutes with just a few screws.
  • Limited lifetime warranty.



Improves window performance by redirecting heat back into the home and reducing energy transfer through the window opening.

Cooler Summers

Reduces sun-generated heat entering through the window to help keep your home comfortable.

Quiter Room

The extra layer of glass and dead air space created when you add another window blocks the noise of traffic, lawn mowers and loud neighbors. 


ComfortSEAL interior windows are available in Clear and Low-E glass options.

Comfort Seal Window Types

Proven 75% air leakage reduction

Based on air leakage testing performed by an independent laboratory of a Larson I200 window in accordance with AERC 1.2 Physical Test Methods for Measuring Energy Performance Properties of Fenestration Attachments.  Actual results may vary based on the existing window.

Remarkable weatherstrip presses inside window frame for an air-tight seal


Proven 50% noise reduction

Based on STC testing performed by an independent laboratory of a Larson I200 window installed with a 2-in airspace over a wood primary window with 1/8” glass and 3/4” insulated glass with two panes of 1/8” glass. Actual results may vary based on the existing window and types of noise present.

Measure your opening width at the top, center and bottom. Measure your opening height on the sides and middle. Use the smallest measurement. The comfortSEAL window is automatically sized to fit the opening.