Thanks but I think you are mistaken. There is no limit on the credit for a geothermal heat pump (see Part 1 of Form 5695) except that it’s nonrefundable (can’t exceed the total tax). You can verify this by entering a reasonable cost of a geothermal system (>$50,000) in TurboTax. The actual rebate from Mass Save is $15,000 which would change the credit by $4500 which IS significant.
