Why This Matters
Single-pane windows — still common in California homes built before 1980 — have almost no thermal resistance. Low-e retrofit film can cut their solar heat gain by 40–60% at a fraction of the cost of replacement.
Near SolarSesame 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
The installation process is non-invasive: clean the glass, apply the film with a slip solution, squeegee out air pockets, and trim to fit. No construction, no permits, no disruption.
Perforated film solves the privacy-versus-light tradeoff for street-facing rooms. The micro-hole pattern maintains outward visibility from inside while blocking the view from outside during daylight hours.
Retrofits existing glass with a low-emissivity coating for improved thermal performance.
Climate & Solar Performance
Properties near SolarSesame 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
The best time to schedule installation is in the morning, before the glass heats up. Hot glass causes the slip solution to evaporate too quickly, making it harder to position the film correctly.
Install time
30–45 min
Per window
$150–$400
Cure time
30 days