The usefulness of night temperature setback - a temporary reduction in heating setpoint temperature - is often a contentious issue. Because of the reduced heat losses associated with lower room temperatures, temperature setback may logically lead to energy savings. However, the amplitude of these energy savings is highly dependent not only on setback amplitude and duration, but also on the building and its thermal mass. The higher the thermal mass, the lesser the energy savings. <!-- Tariku 4.4 % savings --> A potential drawback of night temperature setback is the increased energy needed to reheat spaces. The resulting morning peaks may be detrimental for some systems. Also, comfort might be compromised if reheating does not start early enough. Conversely, lower temperatures at night may be beneficial for sleep.