Measuring Your Storm Windows

  • Measurment of your windows are determined by measuring the existing opening as shown in the diagrams below.
  • NOTE: Low E Storm Windows are built to the exact “tip to tip” measurements submitted in the order form. It is recommended that you reduce the windows by 1/8″ on each side (1/4″ width and 1/4″ height) to give some space for adjustment.
  • The ordered height of the window is reduced by 1″ in order for the “sill expander” to be fitted and still end up with the proper overall measurement. The sill expander allows for up to 1/2″ of extention for the bottom of the window to meet the angled sill of the window opening.




Installing Your Storm Windows.

  • Determine the top of the window unit, noting the sash operation. The expander should be installed on the bottom of the unit. (NOTE: some models have the expander installed at the top of the unit for shipping only. Remove the expander from the top and reinstall it at the bottom in this case.)
  • Position window into the opening to check for proper fit and clearance.
  • Remove the storm window and caulk the surface on which the storm window will be mounted with exterior window and door caulk. CAULK THE HEAD AND JAMBS ONLY. NOTE: To allow for proper drainage, do NOT caulk the sill.
  • Reposition the window into the opening with the top of the window pushed up snug to the top of the opening. Temporarily secure the top corners of the window with two (2) isntallation screws.
  • Adjust expander so that it makes even contact across bottom of existing window sill.
  • Square up the window unit, then install the remaining installation screws making sure the “gap” between the window and the frame are even (the ideal gap is 1/16 on each side of the window).


“This Old House Magazine”

In this highly informative article entitled “Weathering the Storm” from “This Old House magazine”, TOH general Contractor Tom Silva demonstrates the measurement and installation of a replacement storm window.

tom silva

“Tom demonstrates how to measure for and install an aluminum exterior storm over a double-hung window. (Outward-swinging casement or awning windows require interior storms.) Tom has the window up in less than 10 minutes, but while installation is simple, he says, there are still ways to mess it up. “The most common mistake people make is to caulk the storm’s bottom edge, along the windowsill,” he says. That can trap water that leaks in or condenses on the inside of the glass. “You want to give water a chance to escape before it causes any damage.”

  • Photos: Keller & Keller Photography


Detailed Measurement Instructions…

There are 2 ways to measure and install new storm windows:


  1. Blind Stop Mount–Installs the storm window on the exterior “blind stop” of the prime window, inside of the exterior brickmold or casing.

  1. Overlap Mount– Installs the storm window over the exterior brickmold or casing.To measure for your new storm windows, first determine if you would like to use the Stop Mount or Casing Mount installation method. Finally, grab a tape measurer and head outside to measure your windows.It is best to have some help with writing down the measurements as you take them, to reduce the chance of a mistake.

    Keep in mind that there are no “standard” or “typical” sizes and each window is unique and different, even on the same home.

    NOTE: Each window is built to the exact “tip to tip” size that is ordered with no size deduction. Windows come with sill expanders.

    FIRST: Measure the width of the storm window mounting location on your existing window’s exterior within 1/8″ in 3 locations (Top, Middle, and Bottom) of each window–use the smallest of these measurements.

    NEXT: Measure the height of the storm window mounting location on your existing window’s exterior within 1/8″ in three locations (Left, Center, and Right) of each window–use the smallest of these measurements.

    FINALLY: Check the opening for square by measuring the mounting location diagonally from upper right to lower left and upper left to lower right. The dimensions should be the same if the opening is square.Continue this process for each window that requires a storm window.Once all of your measurements are complete, see if you have any quantities of windows that have the same measurements and group them together for easier ordering–then go to your computer and click the “Order Now” button found on every page!



Features & Benefits


Sash Features:

  • All Vinyl Mechanical Sash Fin Seal Weather-Strip
  • Interlocking Meeting Rails
  • Double Weather-Strip Meeting Rails
  • Dual Spring Loaded Plungers

Frame Features:

  • Triple Track Pocket Frame
  • Fusion Welded Frame
  • Stainless Steel Springs in Jamb
  • 1/16″ Manufacturing Increments
  • Contoured Exterior Design Multiple Sash Opening Positions
  • Overlap Flange for Easy Mounting

Standard Features: Special Notes:

  • Low E Glass
  • Self Storing Half Screen
  • Single Strength Glass only available up to 11.99 square feet
  • Double Strength Glass only available up to 21.99 square feet
  • Stainless Steel Matching Insulation Screws
  • Tempered Glass MUST Be Double Strength
  • Tempered Glass Only Available Up To 24.99 Square Feet

Optional Features:
Full Screens NOT Available

  • Snap On Sill Expander (sill expander downsizes window by 1” in height)
  • Double Strength Glass

Options (Added To Base Price):

  • Oriel Window
  • Double Strength Clear Glass
  • Double Strength Low-E Glass
  • Tempered Glass
  • Oversize Charge
  • Painted Exterior


Sizing Parameters Double Hung 2 Lite Slider 3 Lite Slider Picture Window
Minimum Width 12″ 22″ 44″ 12″
Minimum Height 22″ 12″ 12″ 12″
Maximum Width 48″ 84″ 104″ 64″
Maximum Height 84″ 48″ 48″ 52″