How to Clean Storm Windows Before Winter

To clean a storm window you have to move the panel out of the way, because the dirt people actually notice is not on either face you can reach. It is on the back of the storm and the front of the window behind it. On a triple track that means lifting the glass panel out of its channel. On an old wood storm it means taking the whole unit off the house. October is the month for it in Minnesota, while the weather is mild and before the storms get closed up for the season.

Why the glass behind a storm window goes hazy

The space between a storm window and the window behind it is not sealed. It is vented on purpose, with small slots along the bottom of the frame, so moisture can drain back out instead of sitting against the sash. That venting is also how the dirt arrives. Pollen, road film and dust drift through, settle on the two inside faces, and stay there because nobody can reach them.

Winter adds a second layer. Warm indoor air meets cold glass, condensation runs down the inside of the storm panel, and whatever was dissolved in that water dries at the bottom as a hard gray line. A few seasons of it is what makes an old storm look permanently fogged.

Worth separating from an actual failure: a modern double pane window is sealed, and when that seal breaks the haze sits between the panes where no cleaner can reach it. That one is a glass replacement. A storm window is not sealed, so the haze there is only dirt, and it comes off.

Aluminum triple track storms

These are on most postwar houses around here. Each opening holds three panels in two channels: an upper glass, a lower glass and a screen. To get one out, look at the sides near the bottom for two small spring clips or lift tabs. Squeeze them in, tilt the top of the panel toward you, and lift it free of the channel. They go back in the same way.

Number the panels with painter's tape before you pull them. Openings on the same wall are rarely identical, and a panel that is an eighth of an inch wide will not seat in the next window over. Write the room and the position on each one. Then wash both faces flat on a towel in the yard, dry the channel while the panel is out, and put it back the same day.

Wood storms that come off whole

A lot of the older houses in St. Paul still have wood storm sash that hangs on hangers and comes off in one piece. They are heavier than they look, and a second set of hands is worth having on a ladder.

Mark these too, since each was built for one opening. Wash the glass with soap and water and keep the wood damp, not soaked. While the sash is down, look at the glazing putty around each pane. If it is cracked or missing, that is the moment to reglaze, because water behind the putty is what rots the bottom rail. Store them standing on edge, not stacked flat, so the frames do not rack.

What to use, and what to keep away from it

Warm water with a few drops of dish soap, a squeegee if you have one, and a folded microfiber towel for the edges. That is the whole kit. A couple of things to avoid:

• A pressure washer. Aimed at a storm window it drives water past the weatherstripping and into the frame and the wall behind it.
• Dry scraping. If paint flecks need a blade, keep the glass soapy and pull one direction with a new blade.
• Abrasive pads on the frames. They dull anodized aluminum and the dull surface holds dirt worse than it did before.

The gray line at the bottom of the panel is mineral, not film, so soap will not move it. White vinegar and some dwell time will. The same approach that works on hard water spots on windows works here.

Pick a mild day. Below about 40 degrees the water sheets off slowly and streaks, and below freezing it sets up on the glass before you can pull it off.

Do it before you close them for the season

Once the storms are down and latched, you are not opening them again until April. Anything left on those inside faces sits there for six months, and it is the glass you look through for the darkest part of the year.

The timing lines up with the rest of the fall work, since the screens are coming out of the same channels anyway. There is more on that in our post on cleaning and storing screens before winter.

Whether it is worth hiring out comes down to how many panels there are. Eight openings on a rambler is an afternoon with a radio on. A two story with twenty triple tracks is why a house with storms runs close to double the glass of the same house with newer windows. Gleam Team handles window cleaning in St. Paul, Minneapolis and the suburbs out to about 25 miles, starting at $99 and backed by the Gleam Guarantee. When you are ready, request a free quote or book a free 10-minute consultation.