To acclimate flooring products is to set flooring materials into the room or building expected to receive the new flooring for a period of time so that the temperature and/or moisture content of the flooring supplies harmonize with the target environment. After acclimation, hydroscopic materials will reach their equilibrium moisture content (EMC).
Flooring products, especially hardwood, expands and contracts based upon the air's temperature and relative humidity. Flooring materials which are not acclimated to their new environment may cause complete installation failure. The necessary time period of acclimation will vary. The general rule is 48 to 72 hours.
Flooring should be placed in an equalized place; therefore, the flooring should not be placed in a location which will be meaningfully warmer, cooler, or more or less humid than the remaining portions of the target area. Acclimation should begin after the building envelope is sealed and the HVAC has been in normal operation for an extended period. That is, the building should be normalized in temperature and humidity before the materials are acclimatized to the building.