How exterior storm windows protect original windows
Original windows are worth keeping. An exterior storm window takes the weather so they do not have to.
What an exterior storm window shields
Weather
Rain, snow and wind hit the outer face of a window first. An exterior storm window takes that exposure so the original sash and glazing stay out of the worst of it.
Sun
Daily sun fades finishes and dries out paint and putty. A storm window shades the original from some of that exposure, and Low-E glass also reduces the heat coming through.
Moisture and rot
Water that sits on a sill or runs down a sash is what wears older windows out. Keeping the original out of the rain, and letting moisture drain through the storm window’s weep holes, helps it last.
Everyday wear
Debris, ice, cleaning and ladders all take a toll. A removable outer layer takes the scrapes so the original does not.
What you get in return
Keep the original character
Original windows often have glass, proportions and details that are hard to reproduce. An exterior storm window lets you keep them rather than replace them.
A cost to compare
Adding storm windows typically costs less than replacing every window. Your own numbers decide it, so compare quotes for both.
Comfort and energy
The still air between the original and the storm window slows heat loss, and Low-E glass adds to that. The result is fewer drafts and steadier room temperatures.
Easy upkeep
The storm window is the surface you clean and care for. Sashes release for cleaning, and the original behind it stays protected.
What to know before you order
Two details shape how an exterior storm window goes in.
Weep holes
Exterior Low-E windows have weep holes at the bottom of the frame so moisture can drain. Never caulk over them.
Blind stop mount
The frame sits in the recess against the blind stop, a trim piece around the opening. It gives a tidy, built-in look.
Overlap mount
The frame mounts over the exterior trim face and covers the edge of the opening. It suits openings with a flat trim surface.
Go deeper
This guide covers why exterior storm windows protect what you have. For older homes in particular, see our guide to storm windows for historic homes, and to compare storm windows with replacement, read how the two stack up.
FAQs
Do exterior storm windows protect old windows?
They help. By taking the exposure to rain, wind, sun and debris, an exterior storm window shields the original window and can slow the wear that older windows show. They do not repair a window that is already damaged.
Are storm windows cheaper than replacement windows?
Typically, yes, because you keep the windows you have and add a layer rather than replace them. Compare your own quotes, since the cost depends on the number and size of your windows.
Do storm windows hurt original windows?
No, when they are fitted properly. Weep holes let moisture drain, and removable sashes make cleaning easy. Make sure the original window is dry and in good order before you add one.
What is the difference between a blind stop and an overlap mount?
A blind stop mount sits in the recess against the trim piece called the blind stop. An overlap mount sits over the face of the exterior trim. Your opening decides which one works, so check the mounting guide before you order.
Why do exterior Low-E storm windows have weep holes?
Moisture can collect between the original window and the storm window. Weep holes at the bottom of the frame let it drain out. Never caulk over them.
Will an exterior storm window change how my house looks?
It adds a frame and glass outside the original window. A slim, low-profile style in a matching color keeps the change small.
Can I still open my original windows?
Yes. Operating storm windows open for ventilation, and removable sashes and screens let you reach the original window when you need to.
Protect the windows you already have
Choose your style, then enter your measurements for a made-to-measure window.