Why This Matters
West-facing windows receive the lowest sun angle in the afternoon — the same angle that drives the highest solar intensity per square foot of glass. This is why west-facing rooms overheat first.
Near HCI Solar in Berkeley, west-facing windows at low afternoon sun angles drive the highest interior temperature increases. This is especially problematic for historic or older home installations, which older single-pane windows benefit most from low-e retrofit film to improve thermal efficiency.
California's Title 24 energy code sets minimum window performance standards for new construction. Window film can bring older homes up to — and beyond — those standards at a fraction of the cost of window replacement.
The Solution
Quality window films carry 10–15 year manufacturer warranties. That's longer than most window treatments and comparable to the lifespan of the windows themselves.
Ceramic film is the premium option: non-metallic, signal-transparent, and highly effective at blocking solar energy. It costs 20–40% more than standard films but offers superior clarity and a longer lifespan.
Retrofits existing glass with a low-emissivity coating for improved thermal performance.
Climate & Solar Performance
Properties near HCI Solar in Solar Car Wash, Berkeley experience afternoon heat gain conditions that make window film particularly effective. Low-E Retrofit Window Film is specifically engineered to address this solar exposure.
Effective against afternoon heat gain
Rated for historic or older home protection
Professional installers available in Berkeley
10–15 year manufacturer warranty
Installation Guide
Professional installation typically takes 2–4 hours for a standard residential job. The installer will clean the glass, apply the film with a slip solution, squeegee out all air pockets, and trim to a precise fit.
Install time
30–45 min
Per window
$150–$400
Cure time
30 days