Thermal mass construction (TMC) operates on the principle that it is more energy-efficient to keep a relatively massive structure at a steady temperature than it is to manipulate the temperature of air. TMC has been hailed as the evolution of residential architecture.
An empty refrigerator uses more energy than a full one. Objects denser that air will better store the cold. Opening an empty refrigerator releases the cold air, while the warm air enters. When the door closes, the unit cycles on and the process repeats itself
Joe Britt, an engineer, says we heat and cool our homes like an empty refrigerator. This is extremely wasteful in terms of energy.
That is why Britt turned to thermal mass construction to build his energy-efficient thermal mass house in upstate New York.
Modern thermal mass houses feature walls and floors made from layers of concrete and insulating foam. Everything is embedded with radiant pipes to make a tight energy envelope that resists thermal gains and losses. This can cut both the heating and cooling loads. As a bonus, these houses are also resistant to fire, termites and rot.
Some thermal mass houses are round, but these are due to personal tastes rather than structural necessity. The exterior of these houses can likewise be finished in different ways.
Thermal mass construction costs about 20 percent more than the traditional stick-built house. However, energy savings, especially in extreme climates, easily offset this liability.
Most TMC constructors use manufactured precast panels that are delivered to the job site. A respected brand is Dow Chemical Company’s T-Mass. Using these precast panels, walls can go up in one day with proper equipment. The downside is that last-minute changes in design are not feasible.
Britt constructed his walls using insulated concrete forms (ICFs). ICFs are less expensive and more flexible than precast panels. However, it takes 27 days to cure the concrete.
Britt says it is easy to regulate the temperature of a thermal mass house because of its massive size and insulating capacity. Using the embedded radiant tubing, a simple loop in the ground and a circulating pump, the interior temperature can be kept steady with minimal energy.
In his own home, he simply uses a normal pellet stove for heating instead of a furnace. He uses a small window unit air conditioner for cooling.
Britt concludes that TMC coupled with a smart design, solar hot water and photovoltaic components can create a self-sustaining off-the-grid structure.