Why This Matters
The afternoon sun angle in Southern California between June and September is low enough to drive direct solar radiation deep into west-facing rooms. Standard window treatments block the view; film blocks the heat.
Near Sunrun in San Francisco, energy-efficient double-pane glass with low-e coatings can be enhanced further with retrofit film. 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.
The marine layer that covers coastal California in the morning burns off by midday, leaving afternoons with intense, direct sunlight. West-facing rooms without film are at their hottest between 2pm and 5pm.
The Solution
Residential window film is the most targeted solution for solar heat gain: it addresses the problem at the source — the glass — rather than compensating with more cooling.
Low-e retrofit film is specifically designed for older single-pane windows. It adds a low-emissivity layer that dramatically improves thermal performance — the most cost-effective upgrade for pre-1980 California homes.
Retrofits existing glass with a low-emissivity coating for improved thermal performance.
Climate & Solar Performance
Properties near Sunrun in Mission District, San Francisco experience low-e glass performance conditions that make window film particularly effective. Low-E Retrofit Window Film is specifically engineered to address this solar exposure.
Effective against low-e glass performance
Rated for historic or older home protection
Professional installers available in San Francisco
10–15 year manufacturer warranty
Installation Guide
Some installers offer a complimentary solar assessment — they'll visit your property, map your sun exposure by orientation, and provide a written film recommendation before you commit to installation.
Install time
30–45 min
Per window
$150–$400
Cure time
30 days