A comparison between measured and calculated heat losses through a slab-on-ground floor

Abstract The time-dependent theory of the thermal coupling between a solid floor and the ground, previously developed by the author, is compared for the first time with experiment, using heat losses measured from the insulated floor of a small house over a period of two years. A new expression for the time-dependent heat losses from an arbitrary central region of the floor is obtained and compared with measurement, and measured temperatures at the surface of the concrete floor (under the insulation) and at 1 m depth are also compared with the theory. Because previous work has shown that for an assumed typical ground conductivity of 1.4 W m−1 K−1 the predicted average heat loss is considerably higher than that measured, the measured average values have been added to the calculated time-dependent components for the purposes of comparison. Agreement with experiment is good, particularly for the total heat losses, and the sensitivity of the calculations to the ground thermal properties, which are often unknown, is fortunately not large.