@Dave Carpenter
In short, it depends on the lender. Keep in mind that it is the lender who is the client of the appraiser. Yes, 99% of the time it is the borrower who pays for the appraisal but guess what, it is the lender’s report and the lender decides the purpose of the appraisal. I know what you're thinking and I agree: That doesn't seem right.
The overwhelming percentage of appraisals are done using the sales comparison approach. I would be hard pressed to find any lender or appraiser who regularly uses the income approach to valuing any property with fewer than five units. in fact, an appraiser might even lose their license if they did that.
Lastly, appraisers have not been provided guidance on airbnb by the uniform standards of professional appraisal practice. to date, the argument is that the income generated from short term rentals is so highly variable no lender can bank on an amount provided by the borrower, even if the borrower provides a plethora of documentation another supporting evidence.
The only possible wiggle room would be if a certified general appraiser uses other similarly zoned motels, hotels or the sort.
But please, if you're looking at the massive amount of income generated through short term rentals and believe that an appraiser is going to use those numbers to determine value, I'm sorry to inform you that this is not going to happen. However, check and recheck and then check again with your loan officer or commercial banker.