Window Maintenance Checklist: A Yearly Routine

Window maintenance comes down to a short yearly round: clear the weep holes and tracks, check the caulk and weatherstripping, clean and lubricate the hardware the way the maker says, and look over the screens and the finish. Marvin's owner's manual for its Vivid line and Andersen's care guide for casement and awning windows both put that round on a once-a-year schedule, and Andersen suggests every three months in coastal, industrial or agricultural areas ¹².

The warranty reason matters as much as the practical one. The four manufacturer warranties described below exclude damage from poor maintenance or the wrong cleaners and sealants, and Pella's says that failing to follow its installation and maintenance instructions voids all warranties unless the buyer shows the defect is unrelated ⁶. Keeping to the maker's care guide is how you keep that coverage usable.

The yearly checklist

Do these on a dry, mild day. Marvin's checklist starts with safety: use caution on ladders and wear protective eyewear and clothing ¹.

Weep holes

Many windows have small drainage openings at the bottom of the frame. The Department of Energy's Building America Solution Center says that if weep holes are clogged or accidentally caulked, trapped water can build up in the frame and damage framing, sheathing and insulation ³. Its test is simple: mist the outside glass or pour a little water into the interior track, and some should come out of the weep hole ³. If it does not, the guide suggests clearing the hole with a pipe cleaner, small brush or wire hook, without pushing debris further in, and checking for caulk over the holes if you cannot find any ³.

Caulk and weatherstripping

Caulk seals the fixed joint between the window and the wall; weatherstripping seals the parts that open. Marvin's checklist covers both: inspect the exterior caulk around the outer edges of the frame, trim off loose caulk and reseal gaps, and check weatherstripping for damage, noting that paints, stains and varnishes can damage it ¹. Caulk around windows covers which sealant goes where, how often to redo it, where not to caulk and why warranties treat perimeter caulk as the owner's job.

Hardware and lubrication

Andersen's casement and awning guide says hardware screws, especially hinge screws, should be inspected periodically and tightened, recommends a dry silicone spray on moving hardware, and says liquid spray lubricants, including those with acetone, and oil-based lubricants are not recommended ². Its separate lubrication article repeats the warning on acetone ⁸. Marvin's Vivid manual, by contrast, says casement roto-gears should be lubricated once a year with white lithium grease, with a silicone-based spray for hinge joints and locks, after cleaning off dirt and sand ¹.

The two makers name different products for similar parts, which is the point: use what your own window's manual says. If a crank still grinds or a lock will not catch after cleaning and lubrication, the part may be worn; window repair cost lists what hardware repairs run.

Screens and tracks

Marvin suggests removing screens, laying them flat, rinsing off dust with a garden hose and letting them air-dry completely before putting them back ¹. Its manual also warns that a screen will not stop a child from falling out of a window ¹, and Milgard's warranty says its screens are not intended to hold back people or objects ⁷. Tracks and sills collect grit that wears rollers and blocks drainage; Marvin's checklist says to clean sand, dirt and dust from hinges, sills and tracks ¹. Torn mesh or bent frames are covered in window screen replacement.

What warranties say about maintenance

Each manufacturer's document is different, so read the one for your series and purchase date. Four current examples:

• Pella (vinyl windows and patio doors, 2023 document): failure to comply with Pella's installation and maintenance instructions voids all warranties unless the buyer clearly shows the defect is unrelated; the exclusions also list improper maintenance and applied sealants or caulking ⁶.
• Andersen (400 Series and 200 Series, revised September 8, 2023): excludes improper maintenance, naming brick wash, razor blades, sealants, sanding and improper washing, and failing to seal and maintain exposed wood ⁵.
• Marvin (effective January 12, 2026): excludes failure to follow Marvin's care and maintenance instructions, failure to properly treat, seal and maintain exposed wood, and use of brick wash, razor blades or other inappropriate cleaners or chemicals ⁴.
• Milgard (replacement products, effective January 1, 2026): excludes lack of product maintenance and lack of use of operable windows, saying panels should be opened and closed monthly, and damage from harsh chemicals such as brick wash, acids, abrasive cleaners or solvents ⁷.

Three habits follow. Clean with what the maker approves and keep razor blades and abrasives off glass and frames; Marvin's manual says not to use razor blades, knives or scrapers on glass ¹. Keep caulk off the frame itself. And on wood or wood-clad windows, keep the finish sealed: the Andersen and Marvin exclusions above both name exposed wood that was not sealed and maintained ⁴⁵. Window warranties explained compares the full terms, including labor and transfer.

When maintenance is not enough

A yearly round keeps working windows working. It does not fix a failed glass seal, a frame out of square or rot. Signs to stop maintaining and start asking: fog between the panes (see foggy window between panes), soft wood at the sill, caulk that reopens within a season, or a sash that will not lock even with new weatherstripping. Rotted window frame: repair or replace covers the wood problems, and the repair or replace windows guide works through the decision by symptom. How long a well-kept window lasts depends on its material; how long do windows last lists the published ranges.

If the checklist turns up a problem that needs a new window, you can compare quotes from window installers and ask each one which maintenance its warranty expects.

We are not affiliated with the manufacturers named.

About these figures

• ¹ Reported: Marvin Vivid owner's manual (February 2026) annual checklist, once-a-year roto-gear lubrication, screen cleaning and fall warning, track cleaning and glass cleaning cautions, checked October 26, 2026.
• ² Reported: Andersen casement and awning care guide on yearly inspection, every three months in coastal, industrial or agricultural areas, hinge screws and lubricants, checked October 26, 2026.
• ³ Official record: Building America Solution Center guide on weep holes, the drainage test and cleaning, last updated July 30, 2025, checked October 26, 2026.
• ⁴ Reported: Marvin limited warranty effective January 12, 2026, care and maintenance, exposed wood and cleaner exclusions, checked October 26, 2026.
• ⁵ Reported: Andersen 400 Series and 200 Series limited warranty revised September 8, 2023, improper maintenance and exposed wood exclusions, checked October 26, 2026.
• ⁶ Reported: Pella vinyl window and patio door limited warranty (2023) clause on installation and maintenance instructions and its exclusions, checked October 26, 2026.
• ⁷ Reported: Milgard replacement product warranty effective January 1, 2026, maintenance and monthly operation exclusion, harsh chemicals and screens, checked October 26, 2026.
• ⁸ Reported: Andersen lubrication article on periodic lubrication and avoiding acetone, checked October 26, 2026.