Much has been said about insulation, alternative heating systems, etc. But the essential problem is “thermal comfort.” We tend to think of temperature alone as the condition dictating comfort, but air velocity, clothing, activity, mean radiant temperature and relative humidity also contribute to thermal comfort. The most overrated contributor to comfort is relative humidity. A typical winter indoor relative humidity may be 25 percent. If the relative humidity were increased to 40 percent, the thermostat, for an equal comfort level, could be set back one degree. But the energy required to evaporate the water would take more energy than the energy saved by the lower thermostat setting.
Posted Oct. 10, 2008, at 7:11 p.m.