The way the ductwork in your house is designed is as important as the way it's built. You may not have thought about it, but good ductwork design can make a noticeable difference in your energy bills. Badly designed ductwork won't work efficiently, and it can wear out your HVAC system by making it work harder than it should. You'll also have trouble keeping your home at a comfortable temperature.
Guidelines for good ductwork design:
The ducts should be located inside the air conditioned or heated part of the house. Ducts in the non-conditioned areas will work less efficiently. When it's necessary to install a duct in the attic or crawlspace, use an insulation with a higher rating than required. This is also important when your home has a variable-speed furnace and air conditioner.
All the joints between ducts need to be fastened together mechanically. They also need to be sealed with mastic (a type of putty) and fiberglass mesh. The installation crew should also check for air leakage after the install and confirm it doesn't exceed five percent of the total air flow rate.
Hard ductwork is preferred over flexible styles. If you're retrofitting an older house, you may need to use flexible ductwork, but it's less efficient than hard ducts and easier to damage. It's also hard to install and seal correctly.
Dampers (the device inside the duct that regulates airflow) work better when they're installed closer to the end of the duct instead of near the supply register. This allows you, or the installer, to more accurately balance the system. The dampers also need to be fixed in position after balancing.
Supply outlets (the vents that supply conditioned air) should be on interior walls so the heated or cooled air has less distance to travel.
If you have a larger two-story house, think about installing two separate heating and cooling systems with separate ductwork. Two systems, along with good ductwork design, will work more efficiently in two-story or large homes.
If you're building a new home, and need quality ductwork design, contact Air Assurance in Broken Arrow.
Our goal is to help educate our customers in the Tulsa and Broken Arrow, Oklahoma area about energy and home comfort issues (specific to HVAC systems).
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