Slab-on-grade floor construction techniques are used extensively in the United States in climates where cooling is a prominent part of the annual conditioning load. This paper report on an investigation of the effect of insulation on the thermal performance of slab-on-grade residences in climates where both heating and cooling performance must be considered. The study investigated the thermal losses from both uninsulated and insulated slab-on-grade floors for an 1800 square foot (167.1 square meters) residence typical of those being constructed in the region. It was determined that insulation was as important to the cooling performance of the house as it was to the heating performance. It was also determined that care should be exercised in the placement of insulation if one is to gain its full benefit. The slab edge was found to account for a large part of the total perimeter loss and any insulation strategy that failed to interrupt this thermal bridge was ineffective.

KEYWORDS: thermal bridges, thermal insulation, USA, climate, deserts, air conditioning, slabs, housing, heating, performance, energy conservation, insulated housing.