The HVAC Questions Sacramento Homeowners Google Most (Answered Honestly)

No. Setting back 4–7° while you're out saves money, even accounting for the recovery cycle. What you shouldn't do is set back 15° in a poorly insulated home — the system may never catch up during a 105° afternoon.

Generally no. Closing more than about 20% of your vents raises static pressure, strains the blower and can freeze the coil. If you want room-by-room control, that's what zoning or a mini-split is for.

78° when home, 82–84° away is the efficiency sweet spot. Every degree lower adds roughly 3–5% to your cooling bill. Ceiling fans let most people sit comfortably 2–3° warmer.

Usually duct-related: an undersized run, a crushed flex duct in the attic, a disconnected boot, or no return path when the door is closed. It's almost never fixed by buying a bigger AC.

• Hum with no start: capacitor
• Loud bang at startup: delayed gas ignition — shut it off and call
• Screeching: blower or fan motor bearings
• Rattling outside: loose panel or debris
• Hissing: refrigerant leak or duct leak