Heat Retention in Earth Sheltered Structures — What Works?

Thermal Mass Materials

Thermal mass materials, such as concrete or brick, are effective at absorbing and releasing heat. When designed correctly, these materials can help regulate indoor temperatures and reduce the need for supplementary heating. For example, a 4-inch thick concrete wall can absorb or release up to 2.5 BTU per square foot per hour. In combination with insulation, thermal mass materials can maintain a consistent indoor temperature even in cold climates.

Insulation Techniques

Proper insulation is critical in preventing heat loss from earth sheltered structures. Foam board insulation, such as 2-inch thick SPF, can be used to insulate walls and floors. A well-insulated floor can reduce heat loss by up to 50%. Additionally, using insulation around pipes and ductwork can further reduce heat loss. In a typical earth berm home, insulation can account for up to 30% of the structure’s heat retention.

Design Considerations

Proper design considerations, such as orientation and ventilation strategies, are essential in maintaining a consistent indoor temperature. Earth sheltered homes should be oriented to take advantage of natural sunlight and passive solar heating. Careful consideration should be given to ventilation strategies to prevent overheating and maintain air quality. By combining thermal mass materials, insulation, and design considerations, earth sheltered structures can maintain a comfortable indoor temperature with minimal supplementary heating.