New HVAC system before appraisal?

My husband and I have been living in a property that we rent from his parents. The house will be transferred into our names this month or next and we will be getting an appraisal beforehand. Our HVAC system was making funny noises and we had someone come take a look. The HVAC system is 12 years old and working okay. There is a leak of freon but there is enough to last us until the summer right now. We were quoted $600 to make the repair and add a lb of freon to the system. Once the system stops working eventually, we will need to do a replacement (~$6500). The technician said that the ductwork under the house is pretty old and they recommend replacing that as well if we are doing a whole system replacement ($11,000-$12,000 for both). My question is, do we just do the replacements now before doing the appraisal since it is getting old anyways? I was told that in the future, if we decide to sell, we would be paying takes on the difference between the appraisal and the selling price. I’m not sure how much of a difference that would make in the appraisal. This will not be our forever home, we would rent it out or sell it probably in the next few years. The house was purchased in 2021 for $225,000 in NC.