I"m getting a $2000 tax credit on next years taxes. How does that affect my taxes?

There is a federal tax credit available for heat pumps.   You can find out more about it, here.   If you pay for energy upgrades in 2025, you will be able to take the credit on your federal return when you file your 2025 tax return (in 2026).  

And there are other incentives (rebates) through the state of Massachusetts.   You can find out more about those here.  

1. A state tax rebate is not taxable income on your federal return.

2. A large state tax refund may be taxable later, if you itemized your deductions.

For example, suppose you have $5000 of state tax withholding in 2025 that you enter on your schedule A as an itemized deduction. Then, because of the $2000 state tax credit, you get a $2000 state tax refund that is paid in 2026.  That tax refund may be taxable income in 2026 as a reimbursement of a previous deduction, depending on your other income and deductions. 

3. If you claim a federal tax credit on the device, you must reduce the price of the equipment that you claim on your federal return if the rebate was from the utility, or was a subsidy such as for low income taxpayers.  However, if this is an expected income tax credit, you do not need to reduce the price when you claim the federal credit.