If the replacement doors constitute an energy-saving improvement, you may qualify for a tax credit (not a deduction) of up to $500. This dollar limit is lifetime, so if you’ve already used up the full credit, you can’t take it again even though the improvements would otherwise qualify for it. Be sure to add the cost of these capital improvements (minus any tax credit) to the basis of your home. It will help to minimize gain when you eventually sell it. Note that this tax credit expired at the end of 2016 and it is not clear if Congress will revive it for 2017.
The amount of gain reportable and subject to tax. On certain tax-free exchanges of property, gain is not recognized in the year it is realized.