Canyon winds, SR-91 dust and hillside layouts
Drivers know the Riverside Freeway, SR-91, and the toll road, SR-241, as the main routes into the Hills. For heating and cooling, the more relevant fact is that Santa Ana winds can funnel through the canyon in fall and winter, bringing dust, dry air and, in some years, wildfire smoke. Outdoor coils collect grit, and indoor filters clog faster.
Hillside lots also affect where equipment goes. Condensers may sit on narrow side yards or sloping pads, and air handlers in attics can be hard to reach. Long duct runs to far bedrooms lose airflow, so balancing matters as much as the equipment itself.

