There are no tax credits for buying a house with existing solar panels. And in fact, in some cases, if you are selling excess electricity back to the utility, that may be taxable income, not a deduction.
There is a 30% credit (including installation labor) for the cost of installing a heat pump hot water heater, or a conventional gas, electric or oil hot water heater, provided it meets the required efficiency standard. That standard is:
"meet or exceed the highest efficiency tier (not including any advanced tier) established by the Consortium for Energy Efficiency which is in effect as of the beginning of the calendar year in which the property is placed in service"
You would have to check with the CEE web site, or the manufacturer of the hot water heater, to see if it was listed in the highest efficiency tier for 2023.
This answer has been verified for accuracy by an Intuit expert employee
