The design of your ductwork contributes to your home's comfort, air quality and utility bills. A poorly-designed duct system makes it difficult for your heating and cooling system to operate efficiently and wastes energy through pressure imbalances, air leaks and thermal losses. Let's have a look at the principles of good HVAC ductwork design.
Ducts in Unconditioned Spaces
Locate as much of your ducts as possible inside your home's conditioned envelope to minimize heat loss and gain. Where ducts must be routed through unconditioned spaces, ensure you insulate the affected spans to reduce thermal loss.
Duct Span Length
Situate the air handler as close to the center of the layout as possible to reduce the length of the duct spans. The ducts should have as few turns as possible. Short and straight ducts are more energy efficient than ducts with long spans, frequent bends and excessive right-angle turns.
All your ductwork should be made of approved permanent materials like industry-standard sheet metal and fibreglass. Don't use the cost-cutting technique of conveying conditioned air through building cavities such as wall voids. In the long run, it will prove to be costly and will downgrade air quality.
The supply and return airflow should be balanced to create neutral pressure in your rooms. Airflow imbalances can lead to heat loss, heat gain and backdrafting of exhaust gases from your furnace or fireplace. Your HVAC technician can install air balancing dampers where each branch duct connects to the central trunk duct.
Thorough Sealing and Testing
At installation, all duct segments should be mechanically fastened with sheet metal screws. All joints should be sealed thoroughly with mastic, foil tape or both. Before connecting your HVAC equipment to the ducts, have all the ducts leak-tested to verify their integrity.
Insist on these design principles during the initial installation of your ducts. They will enhance efficiency and comfort, and help you save money on expensive duct repairs. If you'd like to know more about the principles of ductwork design, please contact us at Arpi's Industries. We serve the Calgary area.
Our goal is to help educate our customers in Calgary, Alberta about energy and home comfort issues (specific to HVAC systems). For more information about ductwork design and other HVAC topics, download our free Home Comfort Guide.
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