CASE HISTORY: EARTH SHELTERED HOUSE IN VERSAILLES, MISSOURI

Abstract

Solar energy and earth embankment are two design considerations for reducing the energy input to heating a residence. This report describes how three supplemental heating systems interact with solar energy as a primary heat source. The three supplemental heat systems were (1) electric resistance, (2) heat pump, and (3) wood stove. The electric heating elements were used to calibrate the house energy use as a function of ambient outdoor temperature (degree day). Then, following a schedule developed by the Rural Housing Research Unit, a 16-week testing period was divided into four one-week cycles. One week of each cycle represented the operation of each of four modes in which different heating systems were used. The house thermostat was set at 70°F. It was determined that more energy was necessary to heat the house on cloudy days than on sunny days. The electric heating elements and the heat pump kept the house close to the desired temperature. However, they were the most expensive to operate. The solar system and the wood stove, although less expensive to operate, created significant temperature swings above 70°F in the house. This was due to their uncontrollability, and had these systems been more controllable, these economic benefits would have been many times greater.