Unfortunately, many of us do not truly understand the complexities of comfort, including many homeowners, property managers and service technician. It is common for facilities staff or space occupants to respond to comfort problems by checking the thermostat setting, or -if they are high -tech , they might use a temperature and relative humidity meter. Most of us understand the impact on comfort from air temperature and relative humidity. But ,as it turns out, these factors are only two parts of the human comfort equation. Other important comfort factors are clothing, air velocity, activity level, individual metabolism rates, and the temperatures of surrounding surfaces. A well – balanced system with proper design is a key to comfort and efficiency.