Window Maintenance Guide for California Homes

Window maintenance is not much work. It is a couple of hours twice a year, and most of it is cleaning. The reason to do it is that the parts that wear out, the tracks, rollers, weatherstripping, and sealant, wear out far faster when they are dirty, dry, or ignored.

This guide covers what to do, how often, and what to keep away from your windows. It draws on the published care instructions from Milgard, Andersen, and Pella. Your own manufacturer's guide always wins where it differs. This page is part of our California window guide.

The twice-a-year routine

Do this in spring and again in fall, before the rains.

1. Vacuum the tracks and sills.
2. Clear the weep holes.
3. Wash the frames and glass.
4. Clean and lubricate the hardware.
5. Check the weatherstripping.
6. Walk the outside and inspect the sealant.
7. Wash and inspect the screens.

Each step is explained below.

Tracks and weep holes

This is the most important maintenance on a sliding or hung window, and the one most often skipped.

The sill track on these windows is designed to get wet. Rain runs down the glass into the track, and small slots in the outside face of the frame, the weep holes, let it drain. Milgard describes this as a weep drainage system with vented slots on the exterior bottom of the frame, and says it is normal for water to build up on the sill or outside track during rain. Pella says the same, and notes that weep holes may be located both inside and outside the window at the bottom of the frame.

When the track fills with dirt, dead insects, and leaves, the weep holes clog and the water has nowhere to go but inward.

• Vacuum the tracks. Milgard recommends occasionally vacuuming the tracks on all sliding windows and doors. Use a brush attachment, then wipe with a damp cloth.
• Clear the weep holes. Milgard says to use a soft brush, and suggests a soft bottlebrush, pipe cleaner, or paper clip to gently clear the openings. Pella says to use a small, soft brush.
• Test them. Pour a small cup of water into the track. It should drain out of the weep holes outside within a short time. Milgard publishes a more thorough test for its windows.
• Time it. Milgard's advice is that a good time to inspect and clean weep holes is when heavy rain is expected. In California that means October.

Never caulk over a weep hole, and never let a painter or stucco crew do it. Milgard warns that blocking the weep system can void part or all of the product warranty.

Cleaning frames, by material

The universal method is the gentle one: brush off loose dirt, wash with mild soap and water, rinse, and dry. What differs by material is what to watch for.

Vinyl

Milgard's instructions are to remove large particles with a soft bristle brush, then wash with warm water, mild soap, and a soft absorbent cloth, and wipe dry. It says never to use abrasive or acidic cleaners because they may permanently damage the frame finish, and to test any cleaner in an inconspicuous spot first. Pella warns that cleaning solutions and solvents used on glass may discolor the finish of wood, fiberglass, or vinyl frames, so keep them off the frames. Comparisons with other materials are on our fiberglass versus vinyl page.

Fiberglass

Fiberglass frames have a painted or factory-applied finish. Wash them the same way as vinyl. If the finish is scratched, Milgard's advice for paint-finish scratches on vinyl or fiberglass is to consult a painting professional for touch-up or reapplication.

Wood

Wood is the one frame material where maintenance is not optional. The finish is what protects it. Pella recommends inspecting the interior finish at least once a year, because UV from the sun breaks down paint and stain, and checking exterior paint on wood products for peeling and cracking. Its instruction is that problem areas be touched up as soon as possible to prevent further damage.

Look hardest at the bottom rail of each sash, the sill, and the lower corners of the frame, where water sits. Press with a fingernail. Sound wood resists. More on wood windows is on our wood windows page. If the home was built before 1978, read about lead paint before sanding or scraping anything: see lead-safe work on pre-1978 homes.

Aluminum

Older aluminum sliders are common across California. The frames are durable, but the tracks and rollers wear and the finish can pit, particularly in salt air. Keep the tracks clean, wash the frames with mild soap and water, and rinse well. Our page on aluminum windows covers their strengths and limits.

Cleaning glass, including low-E

Almost every window sold in California now has a low-emissivity coating. In most units the coating is on a glass surface inside the sealed cavity, where you cannot touch it. Some products add a coating on the room-facing surface, which you can.

What the manufacturers say:

• Milgard: clean glass with a mixture of mild dish soap and water, rinse completely with clear water, and wipe dry with a soft cloth. Never use petroleum-based cleaners, abrasive or acidic chemicals, razor blades, putty knives, abrasive pads, or high-pressure water hoses, because they may damage the glass surface or the insulating seal.
• Pella: use an ammonia-free glass cleaner or a vinegar solution on a soft, lint-free cloth, and avoid getting cleaning solutions on the frames. Do not use a razor blade to scrape off stubborn material, because it may leave permanent marks or scratches that could cause the glass to break.

Three practical cautions follow from those:

• No razor blades. This is the most common way new glass gets damaged, usually by a painter or a post-construction cleaner removing paint specks. Tell anyone you hire.
• Room-side low-E surfaces mark easily. Pella notes that a mark may appear on the interior of its dual low-E glass when metal touches the surface, and gives a specific cleaning method. If your glass has an interior coating, find your manufacturer's instructions before scrubbing.
• Be careful with aftermarket film. Applying film to insulated glass can affect the glass and may affect the warranty. Check with the window manufacturer first. See window film versus window replacement.

Wash glass on a cloudy day or in the shade so the solution does not dry before you wipe it.

Hardware and lubrication

Locks, latches, rollers, hinges, and casement operators need to be clean and lightly lubricated. Milgard recommends lubricating hardware at least once a year, and at least twice a year in areas with high salt air.

Clean first. Milgard and Andersen both say to clean hardware with mild soap and water on a soft cloth, wipe it dry, and avoid harsh or abrasive cleaners. Milgard adds that abrasive or acidic cleaners remove the lubricants and corrosion-resistant coatings from the hardware.

Then lubricate, with the product your manufacturer names. The guidance is not identical across brands:

The common thread is to keep oily, solvent-based sprays off window frames and tracks. They collect grit, and some attack vinyl and weatherstripping. Apply lubricant sparingly, wipe off the excess, and keep it off wood, which it can stain.

While you are there, check the screws. Andersen recommends inspecting hardware screws, especially hinge screws, and tightening them if needed. Pella notes that a loose set screw on a casement crank handle wears the crank and the operator stud.

Weatherstripping

Weatherstripping is the flexible seal between the sash and the frame. It is what makes a closed window airtight, and it is a wear item. Milgard's care tips say to check it regularly to ensure windows and doors seal tight.

• Look for strips that are flattened, torn, brittle, pulled out of their groove, or missing at the corners.
• Close the window on a strip of paper. If the paper slides out with no resistance, the seal is not compressing.
• Clean weatherstripping with a damp cloth. Pella says to rinse it with clean water and dry it, and not to use oily lubricants on it.
• Replace damaged strips with the manufacturer's part. Profiles are specific to the window. See our common window repairs page.

Exterior sealant

The bead of sealant where the window frame meets the wall is the outermost water seal, and it is the part of the installation with the shortest life. Pella recommends inspecting the sealant on the exterior perimeter at least once a year and says it is extremely important that it remain intact. It tells owners to pay particular attention to the lower corners of windows and to the joints between windows in a group, and says the sealant should not be cracked, broken, or missing.

When you inspect:

• Look for cracks, gaps, and places where the bead has pulled away from the wall or the frame.
• Check the head and both sides closely. Those should be continuous.
• At the bottom, do not "fix" intentional gaps. On retrofit windows the sill sealant is deliberately left open at intervals so water can drain. Sealing them shut causes problems. Our window flashing and waterproofing page explains why.
• Check that sprinklers are not hitting the windows. Pella specifically warns about prolonged water exposure from sprinkler systems.

Small failed sections can be cut out and re-sealed with a sealant compatible with the frame and the wall. If the sealant has failed widely, or there is staining on the wall inside, have the installation looked at.

Screens

Milgard's method: remove the screen, wash it with mild soap, water, and a soft brush, rinse with clear water, and dry with a lint-free towel. Do not pressure wash them. Check the frame corners, the spline that holds the mesh, and the pull tabs. Replacement and re-screening are covered on our window screen replacement page.

California seasonal notes

For coastal homes, see windows for salt air and fog. For mountain homes, see Tahoe and mountain homes.

What maintenance will not fix

• Fog between the panes. That is a failed glass seal. See why windows fog between the panes.
• Condensation on the room side of the glass. That is indoor humidity, not a window defect. See how to fight condensation on the inside of windows.
• Water staining on the wall around a window. That is a flashing or sealant failure and needs attention soon.
• A frame that is warped, rotted, or corroded through. See how often windows should be replaced.

Sources

• Milgard, Window and Door Care Tips
• Milgard, Frequently Asked Questions (hardware, vinyl, glass, and weep system care)
• Milgard, How to Test the Weep System
• Andersen, Lubricate Andersen Window and Patio Door Hardware
• Andersen, Care and Maintenance Guides
• Pella, Windows and Patio Doors Owner's Manual (2021), retailer-hosted copy

Working with Heritage Exteriors

Ask us to show you where the weep holes are and which care guide applies to your windows when we finish, because new windows only stay good if they are looked after. If yours are past what maintenance can do, we will tell you that plainly. Licensed in California, CSLB #1055919. Call (916) 546-2991.