On this graph, it is even more apparent how the extra thermal mass of the Dave House North helps maintain a lower temperature range. Actually, the more important factor is the time constant, which is a product of the insulation and the thermal mass. Since lots of thermal mass is wasted without proper insulation, the time constant is a more useful factor and represents how long it takes a building to reach equilibrium with a steady state temperature. The Dave House North has a much longer time constant, meaning that it can sustain pleasant temperatures for a longer period of unfavorable conditions. On the 14^th of July, both building are about the same, but over the next few days, as the ambient temperature increases towards 100 ^oF, the Dave House is several degrees cooler than the Andy shack during the day. At night, they are closer, but this is not as valuable as being cool during the middle of the day.