Is thermal mass beneficial for maintaining temperature underground?

Underground Thermal Mass Benefits

Thermal mass materials such as concrete, brick, or stone are ideal for underground homes due to their high specific heat capacity. These materials can absorb heat from the surrounding environment, storing it as latent heat, and releasing it when the temperature drops. By incorporating thermal mass into underground homes, occupants can experience a more stable indoor temperature, reducing the need for heating and cooling systems.

Designing for Thermal Mass Underground

To effectively utilize thermal mass underground, designers should consider the orientation of the home, insulation, and ventilation. A well-designed underground home can be built with thermal mass materials on the north side to absorb heat from solar radiation during the day, reducing the load on heating and cooling systems. The use of phase-change materials, such as concrete with embedded phase-change materials, can also enhance the thermal mass benefits.

Examples of Thermal Mass in Underground Homes

A good example of thermal mass in underground homes is the earth-sheltered home built by architect Malcolm Wells in the 1970s. The home features a large concrete dome with a 24-inch thick thermal mass wall made of concrete and brick. The home remains at a consistent temperature of around 68°F (20°C) throughout the year, with minimal heating and cooling requirements. By leveraging thermal mass, underground homes can provide a comfortable and energy-efficient living space.