There is a bit of a glitch here.
However, first note that only "central A/C" qualifies, not mini-splits or window units even if they are efficient. And you must install the property (A/C) in a home that you own that you use as a residence (but does not have to be your main residence). So you only qualify for 2 $600 credits if you installed central A/C on two different homes that you use as residences.
Some energy improvements only qualify if they are made to your "main home" and you can only have one main home per year. However, this limit is not imposed on central A/C systems. And the law says the $600 limit is "per item".
https://www.law.cornell.edu/uscode/text/26/25C
The instructions for form 5695 have a section for "Married taxpayers with more than one home" which indicates that if two married taxpayers live apart and each has a separate main home, they each qualify and should file 2 separate form 5695, one for each home. However, these instructions seem too restrictive, as the requirement that married spouses must live apart in different main homes only applies to the credits on lines 17-20 (Qualified Energy Efficiency Improvements) but the "main home" limit does not apply to the credits on lines 21-32 (Residential Energy Property Expenditures).
In short, form 5695 and its instructions do not cover the situation where a single taxpayer has two homes, or where a married taxpayer has two homes but the spouses don't live separately. The credits on line 21-31 should (in my opinion) be $600 per home for central AC, if you installed central AC in two different homes that you use as residences, whether you are single or married.
I don't know if you can get this credit using Turbotax. I don't know if Turbotax will prepare two copies of form 5695. You may have to prepare your tax return manually, or see a pro. Possibly you could use Turbotax Full Service to engage a CPA to help you out.
What you need to do is to include 2 copies of form 5695 with your return, one for home A and one for home B. Put the address of home A on form A line 21c, and the AC credit on line 22a-b, and put the address for home B on line 21c of form B, and the AC credit on line 22. On the dotted line to the left of line 30 on both forms, enter “More than one main home.” Then carry the total credits to Schedule 3 line 5b.
But I don't know if Turbotax can be made to do this for you correctly.
