Generally, you cannot write off a generator to prepare for a disaster, as the IRS considers it a personal expense.
However, if a doctor prescribed the generator so you can run essential medical equipment (like a CPAP or oxygen machine) during a power outage, you can deduct the cost as a medical expense. You would enter this in TurboTax under Medical Expenses, but it only to the extent your medical bills are more than 7.5% of your income.
If you are self-employed and used the generator to keep your home office running during the disaster, you can write off a percentage of the cost based on how much of your home is used for business.
If it is a permanent whole-home generator, you can keep the receipt as an addition to cost basis.
