Investors & landlords

This AC unit was purchased because the original unit failed and renters were suffering.  I was restoring property to original condition, not trying to make upgrade or improvement.  I consider this to be a repair and want to expense it that way.  Additionally, I am retired and have had no tax liability for 2 years now.  Nothing changes on my return but now I have to pay someone to do my taxes b/c I do not know how to do this.