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.