Yes. Prospective home buyers who will be adding either of these solar systems, and believe they will qualify for the tax credits, are permitted to reduce their income tax withholding. Reducing tax withholding (up to the amount of the credit) will enable the buyer to accumulate cash by raising his/her take home pay.
Buyers can adjust their withholding amount on their W-4 via their employer or through their quarterly, estimated tax payments. IRS Publication 919 contains rules and guidelines for income tax withholding. Prospective home buyers should note that if income tax withholding is reduced and the tax credit qualified purchase does not occur, then the individual would be liable for repayment to the IRS on income tax and possible interest charges and penalties.