Usually, the repair of personal property is not deductible. The improvement can be added into the cost basis of the property, in the event you sell the house, you will get less captial gain. such as replacement of the AC.
If the loss is due to the casulty loss:
Figure the amount of your loss using the following steps.
1)Determine your adjusted basis in the property before the casualty or theft.
2)Determine the decrease in fair market value (FMV) of the property as a result of the casualty or theft.
From the smaller of the amounts you determined in (1) and (2), subtract any insurance or other reimbursement you received or expect to receive.
For personal-use property and property used in performing services as an employee, apply the deduction
limits, discussed later, to determine the amount of your deductible loss.
Individuals may deduct personal property losses that are not covered by insurance or other reimbursements, but they must first subtract $100 for each casualty event and then subtract ten percent of their adjusted gross income from their total casualty losses for the year.