thermal mass

Syllable breakdown

Dictionary meaning

the capacity of a material to absorb, store, and slowly release thermal energy, moderating temperature fluctuations within a building and reducing the need for mechanical heating and cooling; materials with high thermal mass include concrete, brick, rammed earth, stone, and water; in a well-designed passive solar building, thermal mass elements placed in direct sunlight absorb heat during the day and release it slowly through the evening, stabilising internal temperatures; in hot climates, thick-walled earthen or stone buildings with small openings use thermal mass to remain cool during the day and release stored heat at night, a technique codified in Mediterranean and Middle Eastern vernacular architecture for millennia