Window Replacement Timeline: From First Consult to Final Inspection

A window replacement has eight stages. Homeowners tend to picture the fifth one, installation day, and plan around it. The schedule is really set by the stages before it.

This page walks through each stage in order, what happens in it, and what you can do to keep it from stalling. It is part of our California window guide. The on-site steps themselves are described on our window installation process page.

The stages at a glance

Stage 1: consult and quote

A contractor visits, looks at each opening inside and out, talks through frame materials, glass, styles, and installation method, and gives you a written quote. Milgard recommends starting to plan and look at windows around three to six months before your preferred installation date, which gives you time to compare options and choose a contractor before the busy season.

You can shorten this stage by doing two things first. Make a list of your windows with rough sizes, as described in how to measure windows for replacement. And decide what you are trying to fix: heat, noise, operation, appearance, or all of them. Then get quotes for the same scope and compare them using our guide to comparing window quotes.

Stage 2: contract

The contract fixes the scope: which openings, which product line, which frame type for each opening, glass, color, what interior and exterior finish work is included, the price, and the payment schedule. California has specific requirements for home improvement contracts, covered on our page on California window contract requirements.

Two things outside the contractor's control belong here:

• HOA approval. If you live in a common interest development, the association may need to approve the windows' appearance before work starts. Apply as soon as you have chosen the product.
• Financing. If you are using a loan, the approval has to be in place before the order is released.

Stage 3: final measure

After signing, the installing company measures every opening for the actual order. This is separate from the sales measurement. The tech measures width and height at three points each, checks for square, level, and plumb, confirms the frame type for each opening, and checks the items that depend on size, such as bedroom escape openings and where tempered glass is required.

The final measure sometimes changes the plan. An opening that looked fine from a distance turns out to have water damage, or to be too far out of square for a retrofit. Better to find it now than on installation day. Expect a call if anything changes the scope or price, and ask for a copy of the final order schedule to review before it is placed.

Stage 4: order and manufacturing lead time

This is the long stage, and it is the one nobody on site controls. Replacement windows are built to order for each opening. Milgard describes its replacement windows as custom-made for a precise fit.

Lead times vary, and we are not going to give you a number here, because any number would be wrong for some product at some time of year. What we can tell you is what moves it:

• Product line and material. Lead times differ between manufacturers and between one manufacturer's product lines.
• Color. Custom and painted colors can add steps compared with a line's standard colors.
• Glass. Laminated, specialty acoustic, triple-pane, and unusual tinted glass can add time compared with a line's standard glass package.
• Shapes and sizes. Arches, trapezoids, very large units, and bays can take longer than standard rectangles.
• Season. Demand rises in the dry months. Milgard notes that summer is often the busiest time for contractors.
• Supply conditions. Glass, hardware, and resin shortages come and go.

What to do about it: ask for the manufacturer's current lead time in writing when you get the quote, ask again when the order is placed, and ask whether any single item is longer than the rest. If one specialty window is weeks behind the others, you can decide whether to wait or install in two visits.

Stage 5: permit

The permit stage should overlap the manufacturing stage, not follow it. Whether your project needs a permit, and what the application involves, is covered on our page on permits for retrofit windows in California. Some building departments issue like-for-like window replacement permits quickly, over the counter or online; others take longer. Projects that change opening sizes, involve structural work, or sit in a historic district take longer.

The application date matters. The 2025 Building Energy Efficiency Standards apply to permit applications submitted on or after 1 January 2026, and the prescriptive U-factor and SHGC your windows must meet come from the code in effect on that date. The figures are on our page on Title 24 window replacement requirements. The windows should be specified to the right standard before they are ordered, which is one more reason the permit and the order should be planned together.

If your home was built before 1978, the contractor also has lead-safe obligations under the EPA's Renovation, Repair and Painting Rule. See lead paint and window replacement in pre-1978 homes.

Stage 6: installation

Once the windows have arrived and been checked against the order, the crew is scheduled. How long they are on site depends on the number of openings, the installation method, access, and what they find.

For a sense of pace, Milgard's published guidance says a basic replacement typically takes 30 to 60 minutes per window and a full-frame replacement might take two to three hours each, with weather, unexpected repairs, custom work, and cleanup adding time. Those are a manufacturer's general figures, not a promise for your house. In practical terms:

• A retrofit of an average house is typically measured in days, not weeks.
• Full-frame replacement in siding with trim takes longer per opening, because trim and flashing are rebuilt.
• Full-frame replacement in stucco has a long tail. The windows go in quickly, and the stucco patch is finished in coats over later visits, followed by paint. See replacing windows in stucco homes.
• Second-story and hard-access openings add setup time.

Hidden damage is the main wildcard. If an old window comes out and the framing below it is rotted, that opening stops until the repair is agreed and done. A unit rate for repairs in the contract keeps that from becoming a negotiation.

How to get the house ready is on our installation day preparation checklist.

Stage 7: inspection

If the job was permitted, the building department inspects it. Depending on the jurisdiction and the scope, there may be an inspection of flashing before it is covered on full-frame work, and there is a final.

Three things commonly hold up a final:

• Labels removed too early. The Energy Code, Section 110.6(a)5, says the temporary label on a manufactured window shall not be removed before inspection by the enforcement agency. Leave every NFRC sticker on the glass until the inspector has been.
• Smoke alarms. CRC Section R310.2.2 says that where alterations or repairs requiring a permit occur, the dwelling is to be equipped with smoke alarms located as required for new dwellings. Carbon monoxide alarms are separately required in existing dwellings with a fuel-fired appliance or an attached garage. Inspectors often check both at a window final.
• Access. The inspector needs to get to the windows.

Stage 8: punch list and closeout

Walk the job with the contractor before the final payment. Operate every window, check the sealant and trim, and list anything that needs adjusting. Our window installation inspection checklist gives you the full list of what to check and which documents to collect.

Closeout is finished when the punch list is done, the permit is finaled, and you have your paperwork: the contract, the order schedule, warranty documents, and the permit record.

Seasonal timing in California

California lets you install windows in any month, which is not true everywhere. Each season still has a catch. Our page on the best time to replace windows goes into this in detail. The short version:

• Sacramento Valley summer. Dry and reliable for scheduling, and hard on comfort, because your house is open to the heat while each window is out. Ask for an early start and for west-facing rooms to be done in the morning.
• Winter rain, statewide. Sealants and flashing need dry surfaces. Milgard notes that the area around the window must be dry and that heavy rain may mean rescheduling. Build slack into a winter schedule.
• Coastal fog and salt air. Damp mornings near the coast can delay sealant work until surfaces dry.
• Tahoe and the Sierra. Snow and freezing temperatures narrow the practical season. Milgard notes that near-freezing temperatures can keep sealants from curing. See our Tahoe and mountain homes page.
• Wildfire smoke. In a bad smoke period, having windows out is the last thing you want. A flexible contractor will reschedule.

Because the manufacturing stage is the long one, the season you sign in is not the season you install in. If you want windows in before summer heat, the decision has to be made well before it arrives.

How to keep your project on schedule

1. Make your selections before signing, not after.
2. Start HOA approval the day you choose a product.
3. Ask for the current lead time in writing, and which item is the longest.
4. Confirm the permit is applied for while the windows are being built.
5. Review the order schedule before it is placed.
6. Ask that the delivery be inspected before the crew is scheduled.
7. Agree a unit rate for hidden damage in advance.
8. Leave the labels on until the final inspection.

Sources

• Milgard, When Is the Best Time to Replace Windows?
• Milgard, Window Replacement Process: What to Expect
• Milgard, What to Expect and Replacement Windows
• California Energy Commission, 2025 Building Energy Efficiency Standards, Sections 110.6(a)5 and 150.2(b)1B
• 2025 California Residential Code, Sections R310.2.2 and R311.2 (smoke and carbon monoxide alarms)
• 40 CFR 745.83 and U.S. EPA, Lead Renovation, Repair and Painting Program

Working with Heritage Exteriors

Ask us for the manufacturer's current lead time when we quote, and for where the permit stands while your windows are being built. If a date slips, we would rather you hear it from us early than on installation morning. Licensed in California, CSLB #1055919. Call (916) 546-2991.