Context: Thermal mass systems can store solar energy in the form of heat at domestically useful temperatures for daily or interseasonal durations. Thermal storage systems generally use readily available materials with high specific heat capacities such as water, earth and stone. Well-designed systems can lower peak demand, shift time-of-use to off-peak hours and reduce overall heating and cooling requirements.

Question: In what form do thermal mass systems store solar energy?
Answer: heat

Question: What is the system called that can store solar energy in the form of heat?
Answer: Thermal mass systems

Question: What are some of the materials used in thermal storage systems?
Answer: water, earth and stone

Question: What is something that can be accomplished by a thermal mass system?
Answer: reduce overall heating and cooling requirements