Your duct system was probably the state of the art when your home was new. And that's bad news. Back in the day, home builders often viewed ductwork as a convenient opportunity to reduce construction expenses. Ducts included in a new home at original construction were typically not manufactured to remain functional for the life of the home. In addition, builders often cut corners on design and installation of these ducts, utilizing cost-cutting methods that saved time and money but did not enhance energy-efficiency or the service life of the system. In an era of cheap energy, no one paid attention to ductwork hidden in walls, attics or crawl spaces.
Today, however, the present owners of these homes are paying the price — literally — for the errors of the past. Here are some of the ways trouble in your duct system impacts your home:
- A significant percentage of the heated or cooled air in your ductwork may be lost due to leakage. This means that some of what you're paying for in heating/cooling bills is wasted as conditioned air goes into the attic, crawl spaces or walls instead of into living spaces.
- Leaky ducts also cause air pressure imbalances inside the home. Excessive positive pressure in the home will push conditioned air out of cracks and gaps in the structure, resulting in still more wasted energy. Negative air pressure can draw outside air and moisture into the house, resulting in mold and air quality problems.
- Air leaks in return ducts draw unfiltered, unconditioned air from the attic and crawl space into the system, infiltrating the household air with contaminants.
- Design and installation flaws inherent in original equipment ductwork can result in inconsistent heating and cooling throughout the home and cause your HVAC system to run inefficiently, boosting energy costs and adding wear and tear to the system.
Because most of your duct system is located in areas inaccessible to the average homeowner, only an in-house inspection by an HVAC professional with specialized equipment can fully evaluate the status of your ducts. However, certain telltale signs are giveaways that you may be paying for the errors of the past in the here and now.
If you notice bare-metal ductwork in your attic, that's a bad sign. Ducts routed through unconditioned zones like the attic, crawl space or garage are subjected to acute temperatures in the summer and winter. When the ducts are uninsulated, thermal loss through the metal occurs, sapping heat and coolness from the air in the ducts. Bare ducts should be wrapped with duct insulation to prevent thermal loss.
To economize during original construction, segments of original equipment ductwork may have been simply pressed together, then sealed with duct tape. Despite its name, duct tape is actually a very poor material to use when connecting duct segments. It deteriorates quickly and duct segments begin to work loose, spilling heated or cooled air into the attic, wall voids or crawl spaces. Duct segments should be sealed with mastic sealant, then mechanically fastened with sheet metal screws to prevent disconnection.
In an energy-efficient duct design, every supply duct in a room should be served by a dedicated return duct. In the interest of reducing costs, this was often not observed in the past. Instead, a single central return duct was placed in a common area such as a hallway. Unfortunately, when doors to individual rooms are closed, air from the supply ducts is obstructed from reaching the central return. This causes pressure imbalances, air leakage and energy inefficiency. Rooms that lack a dedicated return should have grilles installed in doors or jumper ducts in ceilings to allow the flow of return air.
During original construction, or at a time of renovation or remodeling, a duct branch leading to a room may have been inadvertently capped off. This prevents conditioned air from reaching the room. If you have a room that refuses to heat or cool, suspect an accidentally terminated duct branch in the ceiling.
The largest full-service HVAC contractor in Conroe, Montgomery County and surrounding areas, Conroe Air Conditioning, Heating & Refrigeration is your go-to source for home comfort and energy efficiency. Let us evaluate your home for telltale signs of trouble in your duct system.