The installation process, step by step
1. Measure
Replacement windows are made to order, so the installer measures each opening, usually width and height at several points, to catch openings that are out of square. They also note the window style, which way sliders open, which rooms are bedrooms, and whether any glass sits in a spot that needs tempered safety glass, such as next to a door or by a tub.
2. Choose and order
You settle on frame material, style, color and glass package. For a 2026 job in the Sacramento area, the glass has to meet the 2025 Title 24 limits: U-factor 0.27 or lower and SHGC 0.23 or lower, or U-0.40 and SHGC-0.35 if the whole job is 75 sq ft of glass or less. Windows are then ordered from the manufacturer. Lead time varies by brand and season, so ask for an estimate in writing.
3. Permit
Sacramento County has required a permit to replace windows in unincorporated areas since January 1, 2010, including retrofit work. In the City of Sacramento, the installer applies with a scope-of-work statement under the city's window guidelines (CDD-0327); a separate $132 planning exemption form (CDD-0187) covers qualifying window and door changes outside historic districts. Roseville and Rocklin both publish window replacement permit requirements. In other cities, check with the building division; the regional pattern is clear: Sacramento County has required window permits since 2010, and Rocklin and Roseville run their own window permit processes.
4. Remove the old windows
Crews typically remove and replace windows one at a time or a few at a time, so the house isn't left open. In a retrofit, the old sashes come out and the frame is cut back or removed while the stucco stays. In a full-frame job, the stucco around the opening is cut back so the whole frame comes out. See retrofit windows for the difference.
5. Install
The new window is set level and plumb, shimmed, fastened and sealed. Gaps are insulated, then exterior and interior trim or caulk close it out. Expect the installer to check that each sash opens, locks and seals before moving on.
6. Inspection
The building inspector checks the job at final, including egress on bedroom windows and the energy ratings. Title 24 requires each new window to carry a temporary label with its ratings that must not be removed before inspection. Leave those stickers on the glass until the inspector signs off, even if they're in the way. There's also a permanent label on the unit.
Older homes: lead-safe work rules
If your home was built before 1978, the EPA's Renovation, Repair and Painting (RRP) rule applies. The EPA states that window replacement is always covered, regardless of how much painted surface is disturbed. The contracting firm must be RRP certified and follow lead-safe practices: containment, plastic sheeting, specialized cleanup and verification.
Ask for the firm's RRP certification before you sign, and expect extra setup time and some added cost on pre-1978 homes.
Bedroom windows and egress
Every bedroom needs an emergency escape opening, covered by CRC R319 in the current California Residential Code. For new egress openings, the city's guidelines list a minimum of 5.7 sq ft net clear opening (5.0 sq ft at grade floor), at least 24 inches of clear height and 20 inches of clear width, and a sill no more than 44 inches above the floor.
Replacement windows are handled more flexibly. In the City of Sacramento, CDD-0327 allows minor reductions in the clear opening on a retrofit, as long as the new window still meets the egress code in force when the house was permitted, and the permit documents the year built. Changing a bedroom window's operating style can change the clear opening a lot, so confirm the numbers before ordering. Other jurisdictions may apply this differently; ask the installer how egress will be handled on your permit.
What to ask an installer
- What's your CSLB license number and classification? Window work falls under C-17 Glazing; a B General Building contractor may do it on a multi-trade job. Verify it at cslb.ca.gov.
- Are you RRP certified (if the house was built before 1978)?
- Is this a retrofit or full-frame install, and why for each opening?
- What are the NFRC U-factor and SHGC for every window quoted?
- Who pulls the permit, and is the fee in the price?
- How will bedroom egress be documented?
- What's your workmanship warranty, and who handles a manufacturer warranty claim?
- How long is the lead time, and how many days on site?
Brand questions are covered on our Milgard windows page and the other brand pages.
Contract rules in California
- California law allows no more than $1,000 down, or 10% of the total if that is lower.
- You have three business days to cancel a home improvement contract; five days if you're 65 or older (contracts entered since January 1, 2021).
- Advertising for work that requires a license without holding one is a misdemeanor under B&P §7027.1. Jobs under $500 total in labor and materials don't need a license, but anyone advertising such work unlicensed must say so.
- Get the window list, NFRC ratings, install method, permit responsibility, start date and payment schedule in writing.
What installation costs
Labor alone runs about $150–$300 per window for smaller units and up to $800 for large bay or bow units, according to Fixr's national figures. Fixr puts the average total per replacement window at about $800 installed. No Sacramento-specific price data was found. For full tables by material and type, see window replacement cost in Sacramento, or go back to window replacement in Sacramento.
Main guide: window replacement in Sacramento.