You did make a good point, a local experienced appraiser who has also done an indoor pool or two is a great choice.
To answer your first question, "Do they sell for more, or not?"...it depends on the market (although I have, in my market area, seen only one sell where a premium was not present) - which as you stated - is why a knowledgeable professional proficient in the market should be used - but I would tweak that to suggest asking about their experience with indoor pools.
I am one of those appraisers who chooses not to ignore such a feature. I focus more on the reduced pool of buyers. It is simply not credible to expect buyers to line up to properties with unique features.
Thus marketing time is affected, market appeal is affected. But it is still not invisible. And so I checked our MLS. "indoor pool" gets lots of hits. Unfortunately they all relate to one agent who puts a comment in about the clubhouse of a POA having an "indoor" pool. There was not a single such amenity in our MLS in the past 10 years. However, there have been several hundred that are heated or saltwater...something special in inground pools.
At some point I might try to estimate the contribution of these top quality pools, then estimate a straight line depreciation (physical) and determine the percent deduction for functional obsolescence. Say I came up with 50% functional.
Then I go back to the indoor pool, estimate its age and RCN...estimate the DCN, then take the 50% off. It is a cost-related adjustment...perfectly acceptable appraisal practice found in any textbook, and just do it. You can defend it. You cannot defend arm waving adjustments. you cannot defend ignoring it and pretending it is not there.
so 1 or 2 experiences with something is good enough for you? i hardly think that would qualify anyone for anything with such limited experience. as scott said:
so based on j grant's limited qualifications an appraiser who has done 1 or 2 indoor pools would arrive at one of 2 conclusions:
?? These are your assumptions , not mine.
1. there is no contributory value for an indoor pool (if neither of the sales showed a premium)
2. 50% of the time there is a premium (if one of the two indoor pools showed a premium)
You write some ignorant posts, but this post takes the cake!
You make assumptions and attribute them to me, very odd. (since I said neither of the above) Go ahead and make stuff up...
either way, as scott pointed out in his market, would not arrive at the correct outcome. it takes a lot more than 1 or 2 times to gain reliable knowledge on any particular topic. scott had it right.