How to determine duplex ARV

[Reid Butler]

I'm looking to buy a duplex that is currently rented and livable but needs renovations to bring it up to its full potential. Then, do a cash out refinance after renovation and rental rate correction. Also, setting up one of the units as a medium term or short term rental to increase income.

The problem I'm having is determining what the ARV will be because there are no good comps within the last year. How would an appraiser determine value without local, recent comps?