The Effect of No Air Conditioning on Hardwood Floors

Temperature and Humidity Range

• The guidelines used for hardwood floors are based on the general rules of the American Society of Heating, Refrigeration and Air Conditioning Engineers. The society has determined that the standard indoor environment temperature should be between 70 to 75 F with a relative humidity of 30 to 50 percent. These guidelines determine how floor companies manufacture hardwood floors, how installers acclimatize the floors and how consumers should maintain the floors.

Cupping Definition

• Cupping is a situation that results when the edges and the center of the hardwood floors are not the same height. Specifically, the edges are higher than the center. Some degree of cupping is expected in wide plank boards of at least 4 inches. However, cupping is not normal in wood planks less than 4 inches wide, and significant cupping in even wider plank boards presents a problem.

Causes of Cupping

• Most cupping is caused by moisture content differences between the hardwood floor, the subfloor and the home’s normal moisture content level after installation. For example, the hardwood floor may be stored in a separate area for several weeks before installation and, as a result of being in a different environment, has a lower moisture content level than the subfloor. After installation, the homeowner turns on the air conditioning, which pulls the moisture from the subfloor into the dry hardwood floor, which causes cupping.

Cupping Prevention During Installation

• To prevent cupping, Rusty Swindoll of the National Wood Flooring Association advises hardwood installers to use a moisture meter to check the moisture level of the hardwood floor and the subfloor. The readings for strip flooring should be no more than four points apart; for plank floors, the difference should be no greater than two points. These readings should also match the anticipated moisture content level of the home under normal living situations.

Cupping Prevention After Installation

• Operating the air conditioning is recommended in the summer — and heat is recommended in the winter — to keep hardwood floors dry and to prevent them from cupping. This is especially important for those who live in humid regions with higher moisture content levels. Remember that hardwood flooring is manufactured based on the recommendation to keep indoor temperatures between 70 and 75 F.