We usually set the fan speed to keep the temperature rise of the air passing through the system between roughly 40F-65F depending on the age and efficiency of your system. So, return air temperature may be 70F which means that the supply air measured in the furnace would be 110F to 135F.
exists and is an alternate of . Carbon dioxide is denser than air. The density of carbon dioxide is 1,977 g/L at 0 0C and standard pressure. The density of air (the so called International Standard Atmosphere) is 1,225 g/L. Carbon dioxide is denser than air. <br /> The density of carbon dioxide is 1,977 g/L at 0 0C and standard pressure. <br /> The density of air (the so called International Standard Atmosphere) is 1,225 g/L.
Even methane (natural gas) is lighter than air, but not by much. Carbon dioxide, which is contained in the air we breathe out and is also easily and safely manufactured by mixing bicarbonate of soda and vinegar, is heavier than air. It tends to sink to the floor and accumulate. So it's a good job that houses aren't air tight.