Q. My contractor states that we do not need to acclimate the wood as there is no moisture in the air in the winter and our lot is in an area that keeps the humidity low? Is there a need for acclimating the wood?
A. Re-consult with your contractor and make sure they are following the proper protocol, if not reassess your current contractor. In a new build there are multiple trades that utilize water based products or procedures that add significant amount of moisture to the air. These trades can be tile/stone installers, painters/faux painters, concrete, rock installed (indoors). If this moisture does not have an ability to circulate and evaporate out of the environment, it will just hang in the air in your new build.
Have you been inside a new home under construction when any of the above trades have completed their work or in the process and did you feel very sweaty and sticky? That is the moisture that is present in the air. Use of fans is not appropriate as that is just moving the air and not causing the moisture to dissipate. Use of space heaters is not appropriate as that is only warming the air and not causing movement with evaporation of humidity. If we would bring the wood into this environment and start to install, the wood would absorb all of this moisture and expand.
Once the HVAC/HEATER is turned on and acclimates the surroundings by stabilizing temperature and decreasing the humidity, the wood is going to contract and significant gaping to your floor will occur. If the wood is going to shrink, you want that to occur during the acclimation process and not after installation.
It's fast, easy and done without any expectation or obligation.