Bring your humidity of the house up to 40% for minimum of a week, then bring the wood to the house. Compare the moisture of the wood to the moisture of the subfloor, should be within 6 points (ideally 4 or less) and then install it. It's hard and pretty much taking chances with spacing the wood because of lower humidity, you just can't predict what will happen. But if you are installing engineered hardwood, which I hope you are, increase the humidity in the house by what's recommended by the manufacturer. But regardless you should keep your humidity stable throughout the year within 40-50%. Your low humidity will suck out all the moisture out of the wood.
Voted RFD "Most Helpful Thread of 2012"
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