The single biggest comfort upgrade in a lot of Mountain View homes is the glass. The Valley gets long, bright afternoons and a genuine wet season, and a house still running its original single-pane aluminum or wood windows feels every degree of it — hot rooms on the west side in summer, drafts and cold glass in the wet winter months, and a heating and cooling bill working harder than it should. A modern dual-pane, Low-E window changes the feel of those rooms more than almost anything else you can do to the exterior.

Bay Area Siding Company is a Larkspur-based siding and window contractor serving the South Bay. We handle the full job: measuring, glass and frame selection, Title 24 paperwork, permitting, removal, flashing and air-sealing, and the final walkthrough.

Ready to move forward? Request an estimate or call (415) 619-5167.

Start with the glass

For a Mountain View home, the glass package is where the comfort and energy savings actually come from:

• Dual-pane insulated glass cuts the heat transfer that makes single-pane rooms swing hot and cold.
• A Low-E coating reflects solar heat and UV — meaningful on south- and west-facing walls that take the Valley's afternoon sun — while still letting light through.
• California's Title 24 energy code sets maximum U-factor and SHGC values for replacement windows. Mountain View sits in the Santa Clara Valley climate zone, and the exact numbers depend on the code cycle in effect, so we confirm the current values at permit time rather than quoting a figure that may be out of date.

If a dual-pane unit is fogging or showing moisture between the panes, that's a failed seal — it can't be repaired, only replaced, and it's one of the clearest signs a window has reached the end of its life.

Frames and brands

Once the glass is settled, the frame material is the next decision — it trades off cost, thermal performance, and how the window sits in your home's style. Vinyl, fiberglass, aluminum-clad wood, and aluminum each land differently. A mid-century ranch or Eichler often wants a clean, slim profile that keeps big openings looking like big openings; an Old Mountain View bungalow usually looks best with a frame that respects the original trim and proportions.

We install and can compare the major lines: Anlin, Milgard, Andersen, Marvin, and Pella, plus aluminum. Start from our window replacement hub and we'll narrow it to what fits your openings and budget.

Retrofit or new-construction install

Two install methods, and the right one depends on the condition of the opening:

• Retrofit (insert) keeps the existing frame and is the less invasive route — a good fit where the frame and surrounding wall are sound.
• New-construction (full-frame) removes the window down to the framing so the flashing can be fully renewed. This is the call where there's rot, water staining, or an opening that was never flashed correctly.

We do both, and we recommend based on what we find at the opening, not a one-size default.

The Mountain View permit reality

Here's a Mountain View-specific detail worth planning around: while the city lets a like-for-like siding re-side go through as a same-day permit, window replacement is not on that same-day list — it runs through the standard building permit process. Because the city treats window replacement as an alteration under the energy code, a Title 24 energy compliance form is part of the submittal. The Building Division (Building/Fire Protection, within Community Development) reviews it, and the city encourages checking exterior changes with Planning first. We prepare the Title 24 documentation and handle the permit so the timeline is predictable.

A note on mid-century glass

Mountain View's Eichler, Mackay, and ranch homes were often built with expansive glazing — walls of windows and sliders that are part of what makes them appealing and part of why they can feel drafty or overheat. Those large openings are exactly where a Low-E dual-pane upgrade pays off most, and where matching a slim, period-appropriate frame keeps the home looking the way it was designed while performing like a modern one.

What affects the cost

We don't quote online because every home differs. The drivers are the number and size of openings; frame material and brand; retrofit vs. new-construction; the condition of the existing framing (rot repair adds scope); glass options like tempered where code requires it or acoustic packages near busier corridors; and access on upper stories. A field measure is where an accurate number comes from.

Frequently asked questions

Do I need a permit to replace windows in Mountain View? Yes. Unlike a like-for-like siding job, window replacement goes through Mountain View's standard building permit process, and a Title 24 energy compliance form is part of the submittal. We handle both.

Will new windows really make my Valley home more comfortable? On single-pane originals, noticeably. Dual-pane Low-E glass reduces the heat gain on sun-facing rooms and the cold-glass drafts in winter, which is the change most homeowners feel first.

Can I keep the look of my Eichler or ranch home? Yes. Slim aluminum or fiberglass profiles keep big mid-century openings reading correctly, and clad-wood or matched vinyl profiles suit older bungalows. Frame and profile are chosen to fit the home.

Retrofit or new-construction — which do I need? Retrofit keeps the existing frame and is less invasive; new-construction removes the window to the framing so the flashing is fully renewed, which is the right call where there's rot or water damage. We assess the openings and recommend.

Get started

We're based in Larkspur and serve the South Bay. See finished work in the project gallery. Doing the exterior envelope at the same time? We also handle siding replacement and James Hardie siding in Mountain View.

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