Carbon-neutral buildings should provide thermal comfort with minimum energy use and minimum greenhouse gas emissions. In the same way that a building that provides an adequate thermal environment with excessive emissions is unethical, a building that reduces emissions at the expense of an uncomfortable and unhealthy environment is unsuccessful. Thermal comfort is affected by several factors that affect the rate of heat dissipation from the body and are usually classified as environmental or personal factors. Radiation affects thermal comfort through the radiant exchanges between the body and the surfaces that surround it. The two main theories of comfort are the heat balance or physiological approach and the adaptive approach. The sensation of comfort depends a great deal on the ease with which the body is able to regulate the balance. Thermal neutrality temperature is the air temperature at which a large group of people would not feel hot or cold and the body would be under minimal thermal stress.