What do AC3, AC4, and AC5 mean in laminate flooring? These ratings are commonly used to indicate the abrasion resistance of laminate surfaces and can help buyers choose flooring based on expected traffic levels. However, a higher AC rating does not automatically mean better overall flooring quality. HDF core construction, 8mm/12mm thickness, moisture resistance, locking system, and the intended environment should also be considered. This guide compares AC3, AC4, and AC5 to help you choose the ri