Residential Energy Credit

[Ksmaage]

We installed a new AC system in 2018 and are making payments on it.  Last year taxes I deducted the amount of the payments I made.  Can I do the same this year since I continued to make payments on the AC system?

[Critter]

Well you messed up ... you were supposed to take the entire credit for the entire cost on the 2018 return so you must amend the 2018 return to get the rest of the credit .

Per the IRS : 

Costs.

For purposes of both credits, costs are treated as being paid when the original installation of the item is completed, or, in the case of costs connected with the reconstruction of your home, when your original use of the reconstructed home begins. For purposes of the residential energy efficient property credit only, costs connected with the construction of a home are treated as being paid when your original use of the constructed home begins. If less than 80% of the use of an item is for nonbusiness purposes, only that portion of the costs that is allocable to the nonbusiness use can be used to determine either credit.

[Ksmaage]

Ok. Thank you for the reply.  Is it too late to amend last years return?  And is it worth it?  I read somewhere that there is a maximum amount of credit.

[Critter]

The max credit was $500 and you have 3 years to amend.