Two things shape almost every window project around Clear Lake: the heat, and the fire risk. Summers here are long, hot, and high in UV off California's largest natural lake, so the glass you pick has to manage solar heat gain — and much of Lake County now sits in high or very-high fire-hazard territory, where the glazing itself can be regulated. Bay Area Siding Company, a Larkspur-based (Marin) siding and window contractor, installs replacement and new-construction windows across the City of Clearlake and the unincorporated communities around the lake, handling measurement, glazing selection, permitting, removal, flashing, and air-sealing.

Request an estimate or call (415) 619-5167.

Start with the two decisions that matter most here

Solar heat gain, not just insulation. In a hot, sunny climate like Lake County's, the number to watch is often the solar heat gain coefficient (SHGC) as much as the U-factor — a low-SHGC, Low-E dual-pane unit keeps the summer sun from cooking your interior on the south and west faces. California's Title 24 energy code sets the maximum values a replacement window has to meet, and those depend on the climate zone and the code cycle in force, so we confirm the current numbers at permit time rather than quoting a figure that may have moved.

Fire-zone glazing where it applies. On a designated fire-hazard parcel, California Building Code Chapter 7A can govern exterior openings — typically calling for multi-paned units with at least one tempered pane when an opening is altered, among other requirements. Whether that applies to your home depends on your parcel's designation and whether the work is treated as a repair or an alteration. Given that Cal Fire's 2025 maps expanded the very-high zones across the county, this is worth confirming early, and we handle it during scoping.

Signs your windows are due

Older, modest homes are common around the lake, and their original windows tend to give themselves away:

• Drafts and hot or cold spots right at the glass, even when everything's shut
• Fog or moisture trapped between the panes — a blown seal that can't be repaired, only replaced
• Sashes that stick, drop, or won't latch — swollen, painted-shut, or worn out
• Cooling bills that climb every summer behind single-pane or clear dual-pane glass
• Soft frames, staining, or rot at the sill

Two or more of these usually means replacement is the better long-term move than another round of repairs.

Getting the specification right

• Glass package. Dual-pane insulated glass with a Low-E coating tuned for this climate — prioritizing solar-heat-gain control for the sunny exposures. We match the package to how much sun each opening actually takes.
• Frame material. Vinyl, fiberglass, aluminum-clad wood, and aluminum each balance cost, thermal performance, and looks differently. On older lake-area homes with wood detailing, a clad-wood or a well-chosen profile keeps the character of the opening.
• Retrofit vs. new-construction (full-frame). A retrofit (insert) install keeps the existing frame and is less invasive; a new-construction (full-frame) install removes the window down to the rough opening so the flashing can be fully renewed — the right call where there's rot or past water intrusion. We do both and recommend based on what the openings show.

Comparing brands? Begin at our window replacement hub, then read the specifics for Anlin, Milgard, Andersen, Marvin, and Pella. We also install aluminum windows.

Permits: city limits or unincorporated county

Window replacement is permitted work, and which office handles it depends on where you are. Inside the City of Clearlake it's the City of Clearlake Building Department; on an unincorporated parcel — Kelseyville, Lower Lake, Clearlake Oaks, Nice, Lucerne, and the rest — it's the Lake County Community Development Department (Building Safety). A Title 24 energy compliance form is part of the submittal either way. We confirm the authority for your address and manage the permit.

What affects the cost

We don't post prices, because the openings drive the number: how many and how large, the frame material and brand, retrofit versus full-frame, whether fire-zone tempered or multi-pane glazing is required on your parcel, the condition of the framing behind the old units (rot repair adds scope), and access on upper-story or hillside openings. We quote after measuring.

The rest of the envelope

If the walls are aging alongside the windows, we also handle siding replacement and James Hardie fiber cement in Clear Lake, and we serve the wider Lake County area. See finished work in our project gallery.

Frequently asked questions

Do I need a permit to replace windows around Clear Lake? Yes. Window replacement is permitted work with a Title 24 energy form in the submittal. It's handled by the City of Clearlake Building Department in the city, or the Lake County Community Development Department on unincorporated parcels. We take care of it.

I'm on a fire-hazard parcel — do my windows have to be tempered? Possibly. Where Chapter 7A applies, altered openings generally need multi-paned glazing with at least one tempered pane, among other requirements. Whether it applies depends on your parcel's designation and whether the work is a repair or an alteration, which we confirm before ordering.

What glass should I choose for these hot summers? Look for a dual-pane, Low-E unit with a low solar heat gain coefficient for the sun-facing openings — it does the most to keep summer heat out. The exact values that satisfy Title 24 depend on the climate zone and current code, which we verify at permit time.

Retrofit or full-frame — which do I need? Retrofit keeps the existing frame and is quicker and less invasive; full-frame (new-construction) removes the unit to the rough opening so flashing can be renewed, which is the right choice where there's rot or water damage. We assess the openings and advise.

Get started

Get your Clear Lake windows sized, specified for the heat, and installed right the first time. Request an estimate or call Bay Area Siding Company at (415) 619-5167.