Recommendations for a good HVAC system for ADU?

[Bruce P.]

Hi,

My friend is building an approx 610 sq foot ADU in southern california. It looks like the new standard for air conditioners is freon free.

Any recommendations on a good A/C (as well as heating system)? For an A/C, it looks like I need about 14,000 BTUs per hour for a 610 sq foot ADU if my Internet research is to be believed.

[Dan H.]

Originally posted by @Bruce P.:

Thank you @Dan H. @Liam B. @Dennis Maynard @Richard L. - interesting, I didn't know about these. Looks like the only advantage central system might have is lower initial cost and looking nicers (https://comfortmastersdfw.com/air-conditioning/central-vs-ductless-mini-split/#:~:text=According%20to%20the%20U.S.%20Department,require%20less%20maintenance%20and%20repair.) but total cost of ownership is lower for the multi split system.

If you have to install the ducting, I believe the mini split will have lower installation costs (at least in my market).  The two I am currently getting installed have 3 internal units with condensers on roof for heating/cooling 1140’ units for $6870 each (San Diego pricing).  If I were replacing existing HVAC for 1140’ where the ducting already exists, I could likely do a bit better than this but by the time ducting and vents are added, I believe tradition HVAC would be noticeably more expensive.  Also these behave similar to a 3 zone HVAC system and zones add to traditional HVAC costs.

Good luck