Window Replacementin San Dimas, CA
Window replacement in San Dimas needs a building permit, according to the City's own permit page, and a like-for-like swap may be issued over the counter. A change to the opening needs plans. Near historic downtown the City lists a Town Core window brochure we could not open, so ask Planning before you order.
San Dimas opened with the Santa Fe Railroad in 1887, spent decades among citrus groves and packing houses, and became the 70th city in Los Angeles County on August 4, 1960. The houses came with the subdivisions. Census Bureau estimates (ACS 2024 five-year, read through the Census Reporter mirror) put 32.2 percent of the city's 12,370 homes in the 1970s and 21.2 percent in the 1980s, so a large share of local windows is likely more than 35 years old unless a previous owner replaced them. About 15.0 percent of homes predate 1960.
This page covers the permit, same-size swaps versus new openings, downtown Town Core questions, glass labels and heat, fire zones, safety glass and egress, and how an install day runs. The official Municipal Code site (eCode360) refused our tools, so we lean on the City's own pages and say when something comes from a mirror. Price ranges are on our windows page.
San Dimas Building & Safety rules that apply to window work
Where windows permits come from in San Dimas: City of San Dimas Community Development Department, Building and Safety Division.
- The city's web page says you need a building permit to replace, add or retrofit windows, and the Homeowner's Guide says a window or door replacement can use the Single Trade Permit but window change-outs need plans (the city posts a sample window plan).
- The city's Planning FAQ says like-for-like window changes may be issued over the counter. The Planning Division's brochure list includes 'Window Replacement - Town Core' for the historic downtown area; I could not open that brochure, so its rules are not stated here.
- CSLB defines the C-17 Glazing classification as selecting, cutting, assembling or installing all makes and kinds of glass, including building and glazing frames, panels, sashes and doors.
Do you need a permit to replace windows in San Dimas?
Yes. The City's "When do I need a permit" page says a building permit is required to replace, add or retrofit windows, and the Homeowner's Guide says a window or door replacement can use the Single Trade Permit, though window change-outs need plans and the City posts a sample window plan. That sample is an image PDF we could not read, so we do not say what it shows.
A permit means a licensed contractor does the work. California's $1,000 limit for unlicensed minor work stops applying when a permit is needed, so even a three-window swap under $1,000 requires a licensed firm. At the counter, the contractor shows ID, a state license, a City business license and proof of workers' compensation, and signs a Licensed Contractor Declaration.
Building & Safety is at City Hall, 245 E. Bonita Ave., phone (909) 394-6260. The department page lists Monday through Thursday 7:30 a.m. to 5:30 p.m. and Friday 7:30 a.m. to 4:30 p.m., while an older handout gives Friday as 8 to 5.
Like-for-like swap or a new opening: what changes for San Dimas windows
The City's Planning FAQ says simple jobs, such as like-for-like window changes, may be issued over the counter. That fits a swap where each new unit has the same size and type as the one it replaces. If you enlarge an opening, add a window or turn a window into a sliding door, expect plans, because the wall framing and the header over the opening change.
There are two installation methods, and they behave differently. An insert or retrofit unit goes inside the existing frame, so it keeps the stucco and trim but shrinks the glass area slightly. A full-frame replacement removes the old frame to the studs, so the flashing can be redone, but the stucco around it usually needs patching and painting. Ask which method each quote assumes, and who patches the stucco, since one firm often does the window and another the plaster.
Because the City's pages we read do not spell out the permit documents for a size change, ask the counter what drawing it wants before the order goes in.
- Is the quote for an insert or a full-frame replacement?
- Who patches and paints the stucco around each opening?
- Does any opening change size, type or location?
Replacing windows near historic downtown San Dimas: the Town Core question
The Planning Division's brochure list includes one titled "Window Replacement - Town Core," so the City treats windows near historic downtown as a separate review topic. We could not open that brochure, and the Town Core design guidelines the City adopted in 1993 are scanned images with no text we could extract, so we do not state what either requires.
The background is real. The City's Town Core page cites a 1991 survey that found over 320 significant structures and two potential historic districts. The LA Conservancy adds that San Dimas has no historic preservation ordinance, so protection comes through design review, with the Mills Act property tax program as an incentive. For an owner, that means a quick call to Planning at (909) 394-6250 with the address and the existing window type, before any window is ordered. Custom wood or divided-light units take weeks to arrive, and an unexpected review comment after delivery is expensive.
Replacement windows in a 1970s San Dimas house: glass, labels and heat
Heat is the reason many owners replace glass here. NOAA's 1991 to 2020 normals for the closest station, Pomona/Fairplex, about 3 miles from central San Dimas, show average highs of 92.4 F in August, about 70.5 days a year at 90 F or higher and 10.7 days at 100 F or higher. Records at that station rest on only 11 to 15 years of data, and the City's own handout places San Dimas in California Climate Zone 9.
Ask for dual-pane units with a National Fenestration Rating Council label, and ask the seller to write the U-factor and solar heat gain coefficient on the quote for Climate Zone 9. We are not printing target numbers: city handouts disagree on them and the adopted Energy Code text for window replacement was not read for this page. The 2025 Energy Code took effect January 1, 2026, and the plan set should say which edition the counter enforces.
A south or west wall with a large slider gains the most from a low solar heat gain coefficient. A shaded north bedroom window gains little. Spend the money where the sun hits.
Windows in a San Dimas fire hazard severity zone: what we know and what to ask
Fire zones are the next unknown. CAL FIRE's March 24, 2025 map for the City marks Very High, High and Moderate zones, and the City's page says Council adopts them by ordinance within 120 days of receiving the maps, with power to raise a designation but never lower one. A search snippet names Ordinance No. 1325, introduced May 27, 2025, but we could not open it and cannot confirm adoption. The map is a graphic, so we cannot say which streets sit in which zone.
The City's ADU handout requires Wildland-Urban Interface compliance for any ADU in a zone, and the Energy Commission notes a fire-zone exception to the 2025 window U-factor limit for additions. The City pages we read do not list glazing rules for a window-only job in a zone. As a reference point, Los Angeles's own fire-zone checklist asks for multilayer glazing with at least one tempered pane, glass block or glazing with a 20 minute fire rating, but that is another city's rule, not San Dimas's. Ask Building & Safety whether your parcel's zone changes the glass, the frame material or the vents, and look up the parcel before choosing a product.
Safety glass, bedroom egress and bathroom windows in San Dimas
The City's 2025 bathroom handout requires safety glazing where the bottom edge of glass near a tub or shower is less than 60 inches above the standing surface. A bathroom window over a tub therefore needs tempered or laminated glass, and an obscure pattern for privacy is a separate choice. Sliding doors and glass beside doors have their own safety-glass rules that we did not read for this page.
Bedroom egress is the other common trap. A bedroom window must work as an emergency exit, and replacing it with a smaller or fixed unit can break that. We did not read the code's egress dimensions, so we print none. Ask the designer to write the clear opening on the plan, and ask the City for the minimum before you order a smaller replacement.
If you also plan a garage conversion or bedroom addition, the window sizes on those plans are part of the permit, so bundle the questions.
Lead paint, tax credits and install day for San Dimas replacement windows
Federal EPA rules cover paid work that disturbs paint in housing built before 1978. The census age bins cannot isolate that year, but 63.3 percent of San Dimas homes predate 1980, so ask any window firm whether it is certified for lead-safe work. EPA's own pages refused our tools, so we do not quote its thresholds. The federal 25C energy credit does not apply to windows placed in service after December 31, 2025, per the IRS, though many older articles still advertise it.
Permitted work in San Dimas runs Monday through Friday from 7 a.m. to dusk and Saturday from 8 a.m. to dusk, with no Sundays or holidays. A whole-house swap can span several days, because each opening is measured, ordered, delivered and fitted, and the permit card stays posted near the work. Keep furniture back from each wall and plan for the days a room's window is out.
MDG Builders, CSLB #1040337, manages the permit and schedule as general contractor, and a licensed glazing or window firm installs. Ask for each firm's license number and certificate of insurance. CSLB's C-17 glazing class covers installing glass and glazing frames, sashes and doors, and we did not verify which classes may do a full replacement, so we say what our subcontractor holds on the proposal. Our subcontractor guide explains the handoff.
Window photos from San Dimas and nearby homes
Window scenes tied to San Dimas and the foothill communities around it, from flashing and glass details to finished openings. Tap a photo to enlarge it.
What windows costs around San Dimas
On the windows page, vinyl replacement runs about $550 to $1,200 per window installed, so 10 to 15 windows for a whole house land near $14,000 to $28,000, and wood or fiberglass sits higher. Three Los Angeles reads sit behind it. Remodeling magazine's 2025 Cost vs. Value report prices vinyl replacement at $23,783 and wood at $27,913, about 83.2 and 81.9 percent recouped at resale. Angi's July 2026 average is $19,356, with a typical range of $16,359 to $22,377. ConsumerAffairs lists $550 to $1,150 for vinyl per window but states no method. None is a San Dimas quote, and we read no City permit fee table, so permit fees are a separate line in a written proposal. The license check guide shows how to verify any firm. Neighboring cities follow their own rules, so compare window replacement in Covina, Glendora, Pomona, Claremont and Los Angeles. Windows in a new room are on our San Dimas room addition page, a bathroom window on the San Dimas bathroom page, a garage conversion window on the San Dimas ADU page, and the San Dimas area page lists every trade we cover in the city.
| What it covers | Typical range |
|---|---|
| Vinyl window, installed, each | $550 to $1,150 |
| Wood or fiberglass window, installed, each | $950 to $2,400 |
| Whole house, 10 to 15 windows | $14,000 to $28,000 |
| Glass options, per window | Double-pane $500 to $2,000. low-E $300 to $1,100. tempered $200 to $700. |
| Remodeling Cost vs. Value 2025, Los Angeles | Vinyl $23,783. wood $27,913. |
| New or enlarged egress opening | $3,200 to $6,500 |
San Dimas window replacement questions, answered
Do I need a permit to replace windows in San Dimas?
Yes. The City's permit page says a building permit is required to replace, add or retrofit windows. A like-for-like swap may be issued over the counter, per the Planning FAQ, while a change to the opening needs plans. Because a permit is involved, a licensed contractor must do the work, even for a job under $1,000.
Do replacement windows need to be lead-safe in San Dimas?
Probably, if the house predates 1978. Federal EPA rules cover paid work that disturbs paint in housing built before then, and 63.3 percent of San Dimas homes predate 1980. We could not read EPA's thresholds, so ask any firm for its lead-safe certification and how it contains dust and debris.
How much do replacement windows usually cost?
Vinyl windows run about $550 to $1,200 each installed, and a whole house of 10 to 15 windows about $14,000 to $28,000. Wood and fiberglass cost more. Those ranges come from Los Angeles sources, not a San Dimas survey, and stucco patching, tempered glass and custom shapes raise the total.
How long does it take for new windows to be installed?
Installation is a few days for a typical house, but ordering comes first and runs for weeks. Each opening is measured, the units are built to order and the permit has to be issued. Work is allowed Monday through Friday from 7 a.m. to dusk and Saturday from 8 a.m. to dusk, so a rushed schedule cannot cheat the hours.
Are double pane windows required in California?
For replacement windows, generally yes. Los Angeles's permit bulletin cites Title 24 as requiring dual glazing labeled by the National Fenestration Rating Council in residential buildings of three stories or less. We did not read San Dimas's adopted text, so ask the counter which edition and numbers apply to a Climate Zone 9 home.
What is the difference between replacement windows and new construction windows?
Replacement windows fit an existing opening, while new construction windows have a flange that nails to the framing before the wall is finished. Most San Dimas jobs are replacement. A full-frame replacement is the closest relative of a new construction unit because it exposes the framing, so ask which type the quote assumes.
Is replacing home windows worth it?
At resale, Remodeling magazine's 2025 Los Angeles report shows about 83.2 percent of a vinyl window project recouped and 81.9 percent for wood. Comfort matters more in a place with about 70 days a year at 90 F or higher, but we found no sourced energy-savings number, so we do not print one.
What size egress window is required in a bedroom?
A bedroom window must open as an emergency exit, but we did not read the code's dimensions for this page and will not print them. Ask Building & Safety for the clear opening required and have it written on the window plan before you order a replacement that is smaller than the original.
Can I still get a federal tax credit for new windows?
No. The IRS says the federal 25C energy credit does not apply to property placed in service after December 31, 2025, and many older articles still advertise it. Check utility and insurer programs instead, and verify any rebate before relying on it, since we did not confirm a California program for windows.
Tell us about your San Dimas windows
Tell us which part of San Dimas the house is in, roughly when it was built, how many windows and doors you want replaced and whether the frames are original, and the first visit will start from the permit question.