I'm adding a HVAC system to my single-storey SFH (1200sqft in climate zone 2, San Jose, CA) and the contractor picked out the following system:
- Furnace: 60k BTU @ 80% Efficiency
- AC: 3 Ton @ 14 SEER
Got me wondering if it's overkill for 1200sqft? General sqft-to-BTU load calculators indicate I would be enough served by going a bit smaller. Let's say insulation is medium in terms of quality and installation. Would it then be better to go for a size down?
- Furnace: 40k BTU @ 96% efficiency
- AC: 2.5 Ton @ 16 SEER
Edit: Did a Manual J calc from loadcalc.net myself. Input R11 insulation in ceiling, and walls, floor tile no insulation, stucco, and double pane windows. Based on the wall dimensions and directions, it came back with only 20k and 17k BTUs for heating and cooling! Not sure if I missed something big here, any advice or is this pretty realistic?