I am installing a DIY solar electric system at my house, which qualifies for the “residential energy efficient property credit”. I purchased much of the equipment in 2019, but will not install it until this year (2020) and will incur additional costs then. Since I incurred over 5% of the cost in 2019, the system qualifies for the 30% credit (instead of the phased-out credit percentage that starts at 26% this year).
I’m unclear how to claim this on Form 5695. Do I need to wait until the system is operational later this year, and claim all the cost on my 2020 return ? Or do I claim the amount I spent in 2019 on my 2019 return, and then the add’l costs on my 2020 return (which form 5695 will presumably somehow allow for the 5% thing qualifying me for 30% instead of 26%) ?