The realistic obstacle on San Bernardino heat pump installs is rarely "will it work", it's the panel and breaker arithmetic. About 60-70% of pre-1980 homes we've quoted in Arrowhead, North Park, and the Mt Vernon Avenue corridor are still on 100A service, and once you add a 30-50A heat pump breaker to whatever's already drawn by the dryer, range, EV charger, and pool pump, you're past 200A demand even before code de-rating. The fix is a meter-and-main swap to 200A. Most of the older neighborhoods also have aluminum branch wiring near the panel that needs pigtail terminations during the upgrade, small detail but it adds time. We pull a separate SCE service permit for the meter swap and coordinate the 90-minute power outage so it lands on a weekday morning when the system isn't running anyway. Newer Verdemont, North End, and 210-corridor tract homes built post-1990 are already on 200A panels with spare amperage, so a heat pump install in those neighborhoods is a clean equipment swap with no electrical work.