How to install an exterior storm window

You can add storm windows to the inside or outside of your existing windows. They are most often installed on the exterior of your existing windows, but you can opt for interior storm windows as well. When you are considering adding storm windows we recommend high performance, Low-E storm windows. Low-E stands for low emissivity. Low-e storm windows can improve comfort for a fraction of the cost of a total window replacement.

Steps to install an exterior storm window

  1. Measure the window
    • Measure the opening width at three locations - top, center, and bottom
    • Measure the opening height on the right, left, and in the center
    • If the measurements differ, use the smallest of the three when ordering a new storm window.
    • Both stock and custom sizes are available at local retailers
  2. Prep the window opening
    • You may need to scrape off some old paint.
  3. Caulk around the sides and top of the opening before you screw the window into place.
    • Exterior storm windows are designed with holes at the bottom to allow water or condensation to drain so do not caulk the bottom.
  4. Check that the window is square and install following the manufacturer’s instructions.
  5. Adjust the expander on the bottom of the window so it’s tight against the windowsill.

Important Considerations

  • A good short-term solution are window insulation kits that come with weather-stripping and plastic film that can be installed with a hair dryer to create a tight seal.
  • Window insulation kits, weather stripping, and Low-E storm windows can be found at your local home improvement store.
  • If you have old windows with cracked glass or rotted frames that require a lot of maintenance and are in total disrepair, replacing them with new high performance windows is probably a good idea.
  • There are non-energy benefits to replacing your windows, such as improved property value and ease of use, but the cost of new windows will not likely be offset by energy savings alone.

If you have questions or need advice, contact us for guidance - we’re always here to help.