Proper ductwork design is one of the most important factors affecting your heating and cooling system’s efficiency. A knowledgable HVAC technician will use the Air Conditioning Contractors of America’s Manual D procedures to size the ductwork in your Coastal Bend home, but beyond that, there are a few other things the technician should do.
Make direct connections – The delivery and return air systems should be hard ducted. This means ductwork, not building cavities, should provide a direct connection for air delivery. Formerly, building features such as wall stud spaces were sometimes used instead of ducts, but building codes now prohibit this inefficient technique.
Plan the return side – A central return system should include return grilles on each level of the house. Ideally, every room with a door and two or more supply outlets should have a return grille. A room with a door and no return grille requires a transfer grille or jumper duct.
Use conditioned spaces – Proper ductwork design calls for ducts to be installed in conditioned spaces when possible. Ducts carry conditioned air less efficiently when they pass through unconditioned spaces such as the basement or crawl spaces. Installing ducts in exterior walls also reduces ductwork efficiency. Ducts in unconditioned areas need more insulation than those in conditioned areas.
Keep ducts short – The less distance conditioned air travels, the less opportunity it has to leak out of the ducts. In some homes, installing supply outlets near the interior walls is one option for keeping ducts short.
Connect ducts carefully – Duct sections shouldn’t be merely pushed together, which allows them to leak air. Instead, they should be connected with sheet-metal screws for metal ducts or nylon duct straps for flex-ducts. Joints should then be sealed with mastic.
Keep supply outlets clear – Supply outlets should be placed far from bathroom or kitchen exhaust vents so the vents don’t draw in conditioned air delivered by the supply outlets.
For more guidance on proper ductwork design and other heating and cooling issues, please contact us at CCAC, Inc., where we’re Constantly Concerned About Customers. We provide HVAC services you can count on in Corpus Christi and throughout the Coastal Bend.
Our goal is to help educate our customers in Corpus Christi, Texas 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 Resource guide.
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