Get the size right
Bigger is not better. Right-sized is better.
An oversized air conditioner cools the house in short bursts, shuts off, and starts again. That short cycling creates temperature swings, extra wear, and higher bills. An undersized system runs all afternoon on the hottest days and never quite catches up.
Proper sizing comes from a load calculation that accounts for insulation, windows, sun exposure, ceiling height, and duct location. Attic ducts deserve special attention: on a summer afternoon a Southern California attic can get far hotter than the outdoor air, so leaky or poorly insulated ducts can waste a meaningful share of the cooling before it reaches the rooms.
- A load calculation, not a rule of thumb
- Duct leakage and insulation checked
- Return air sized for the new equipment
- Thermostat location reviewed