Putting toe space grills in houses with A/C and a basement or crawlspace can be a mistake. Normally, the duct is attached to the floor under the cabinet under the cabinet. This pressurizes the space under the cabinet with cold air. The subfloor under the cabinet assumes supply air temperature. If there is any humidity in the crawlspace or basement, moisture will condense on the underside of the subfloor. Conditions are then ripe for mold growth or wood rot. Even if you duct the air all the way to the grille, there can still be problems. The floor in front of the grille will also approach the supply air temperatures. About 10 percent of my business involves fixing problems with damp crawlspaces. The biggest problems are with houses with toespace grilles Avoid toe space grilles unless you are in a very dry climate.
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