There seem to be two points to your question.
1. For 2019, the consolidated budget bill passed in December 2019 retroactively extended the energy savings credits for 2018 and 2019. That includes the "non-business energy property credits" which includes things like windows, doors, and insulation. More about that in a moment.
2. The credits are available if you as a homeowner, make upgrades to your existing home. They do not apply if you are building a new home. (There may be different energy efficiency credits that apply to home builders but I don't know what they are.)
Regarding energy saving improvements, insulation qualifies if it is:
"any insulation material or system (including any vapor retarder or seal to limit infiltration) that is specifically and primarily designed to reduce the heat loss or gain of your home when installed in or on such home and
meets the prescriptive criteria established by the IECC."
So the problem with insulation-backed home siding would be, is it part of a system exclusively designed to prevent heat loss/gain? Does it meet the IECC criteria? (You might ask the manufacturer.) Then, the credit is limited to 10% of the cost of materials only, not including installation. You would need an invoice from your contractor showing materials and labor separately. And finally, there is a lifetime limit on the credit (per taxpayer, not per house) of $500, going back to the first year the credit was offered in 2006.
