Duct heat loss or gain is an important factor to consider when designing a duct system. This aspect of heat transmission will depend on some or all of the following factors:
- Temperature of the air in the duct
- Ambient temperature
- Air velocity in the duct
- Duct insulation
If the temperature of the air inside the duct is different from the temperature surrounding it then either a loss or gain of heat will occur. Denver heating services often include ductwork in their lost of services.
If the ducts are used to convey heat, excessive heat loss from the ducts will reduce the efficiency of the heating system. This will result in a total loss of heating effect if the heat loss occurs in ductwork passing through an unheated area, but it can be considerably reduced with proper duct insulation. Such heat loss can also occur in heated spaces but here it is a problem of poor air distribution.
The same conditions exist when the ducts carry cool air. When air passes through spaces subject to the cooling effect of air-conditioning , insulating the ducts will effectively reduce the amount of heat gain. Proper air distributions will also minimize heat gain in spaces that are partially cooled.
Air velocity will also influence the amount of heat gain in the ducts. High air velocities are recommended when the ducts are carrying cool air because their effect is to reduce the amount of heat gain pickup in the ducts; however, they must be maintained consistent with the acoustic requirements of the installation.
Air Leakage
Air leakage through duct seams and holes will result in the loss of a portion of the air flowing through the duct and a proportionate reduction in the heating or cooling effectiveness of the system. Depending on the seriousness of the problem the ductwork can lose up to 1/3 of the air supply in the manner. It is usually a matter of poor workmanship and can be corrected by sealing the seam cracks and holes by caulking or soldering.
Insulation
Ducts are insulated to prevent excessive heat loss or gain. If the ducts are used to convey heat, excessive heat loss from the ducts will reduce the efficiency of the heating system. The reverse is true of ducts used in cooling systems If the ducts are not insulated, the will absorb heat from the air around them, and system performance will be impaired. To maintain the proper level of performance in a heating or cooling system Denver furnace repair professionals will tell you that you must insulate the ductwork of your home or office.
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