Tore out 10 year old carpet in 3 rooms. Pending hardwood install. I noticed that the padding in all rooms felt dampish ! Moisture meter registered subfloor above 12% in various places in all 3 rooms. I attribute this to the fact that I had had the carpets wet cleaned 2-3 times over the life of the carpet. Last time 2 years ago ! I'm letting the floors dry out for a couple of weeks (fans too), before introducing the hardwood to acclimate for another couple of weeks.

Note: moisture in subfloor is dropping; below 11% everywhere and mostly well under 10%. Still disturbingly non-uniform however. (I probably should invest in an expensive high end moisture meter before nailing (using General MMD4E).....I'll think about this more at 3 AM tonight...)

This goes into the 'experience' category. Backstory: When I was discussing this job with a couple of (reputable/recommended) flooring contractors, the schedule they both talked about went: tearout, followed immediately by wood delivery, followed by 'the kiln dried wood we use doesn't need long to acclimate (24-48 hours tops)', followed quickly by 'nail it down'. No mention of testing for and/or considering moisture syncing. Maybe potentially too time consuming ? Too hard to schedule ? (Kiln dried planking isn't the point is it ? The point is to get the subfloor and the planking synced up moisture wise....) Good topic to discuss when talking with prospective contractors.

There's a lot to consider with this kind of project - as I'm sure the Pros are well aware. (No disrespect intended to anyone here; just more angles/data to keep us DIYers up at night.....)

Newer prefinished material does not need to be acclimated. It comes from the factory in sealed bags/boxes and the MC is ready to go for install in a space that meets the usual criteria (closed off, HVAC running, relative humidity between 40-50% or the manufacturer recommended range for your area, etc)

The only time I acclimate material is then I know the stock has been sitting exposed to non-ideal conditions for some time. This could include, in new construction anyway, unheated houses or condo units that had material delivered too soon or material that has been sitting in a garage for several months waiting for the flooring part of the renovation to come up.

Thanks for your thoughts. D.