Ductwork Duct systems are similar to the arteries and veins in our bodies. They are intended to deliver conditioned air to the space where it is needed, and to return the air from the space back to the equipment. The biggest problems we find with duct systems are: · Poor design and installation · Energy loss through leaks and lack of insulation Poorly designed duct systems don't deliver the right amount of air to the right places, and frequently are too resistant to airflow to do the intended job of air distribution. Often the installation contributes to the problem, adding to the amount of resistance to airflow. The other problems are leaking ductwork and ductwork that should be insulated but isn't. When a duct system is too resistant to airflow or has energy losses from leaks or lack of insulation, the system will be a lot less efficient than it should be. A high efficiency furnace that is rated at 94% AFUE in the lab, can be part of a system that is only 50% efficient due to duct problems. A high-efficiency air conditioner that is rated at 12 SEER in the lab may end up in a system with an efficiency of less than 50% as well. If you were to purchase a car that was rated at 35 MPG, and drove it on tires that were low on air it would not deliver the efficiency you paid for. By the same token if the gas tank had a leak, your fuel economy would suffer. Bad duct systems can hurt the efficiency of your heating and cooling system in the same way. DUCT LEAKS According to a Department of Energy report, "Typical duct systems lose 25 to 40 percent of the heating or cooling energy put out by the central furnace, heat pump, or air conditioner". It is true that most duct systems leak, and some leaks are more costly than others. Leaking ductwork can also be a safety problem. Return Air Duct Leaks. The return air duct brings back to the equipment from the conditioned space. In most homes the return air duct is located within the conditioned space. But many times return ducts are located in unconditioned spaces like attics, crawl spaces and even garages. Leaks in the return duct system in unconditioned spaces will pull unconditioned air into the system. This air needs to be heated in the winter and cooled and dehumidified in the summer. These leaks are very costly and should be fixed. Safety First. Another potential problem with return air duct leaks is when the leaks are in the same room with gas burning appliances. Many gas furnaces and most gas water heaters are "open" to the atmosphere (as opposed to sealed combustion) and have a "draft hood" that allows room air to be mixed with the flu gases going from the appliance to the chimney. If there is substantial leakage of the return air, the flue gases can be pulled into the space through the draft hood- exposing the occupants to the flue gases. In a worst case situation, these flue gases could contain Carbon Monoxide, a toxic, colorless, odorless gas. Return leaks in garages can pull dangerous fumes from automobiles, gasoline cans and other sources into the home. In fact leaks in basement ducts can sometimes pull fumes from garages into the basement through cracks in the walls. If you suspect you may be suffering from exposure to Carbon Monoxide, have a Whole House Comfort Checkup. And if you don't already own a working CO detector - get one today. Supply Air Duct Leaks. Supply air duct leaks when in the conditioned space are not a significant source of energy loss. Supply air ducts in unconditioned spaces however are a huge energy loser. Imagine all your nice warm air in the winter being blown out through duct leaks in the attic. If you have ductwork in an attic, crawl space or garage, and have high utility bills, consult with Apple Heating - we can help. All ducts in unconditioned spaces should be sealed and leak free, and should be insulated. OTHER DUCT PROBLEMS A common problem is ductwork that has more resistance to airflow than it should. Furnace and Air Handler manufacturers design the equipment with blowers selected to provide the needed air flow. Resistance to airflow can be easily measured and compared to what it should be. The pressure in a duct system is known as "static pressure". This pressure is similar to our blood pressure. In this case the system fan (also known as the blower) creates the pressure, instead of the heart. It is the same pressure that is exerted against the walls of a balloon when inflated. High static pressure can cause low airflow. Low airflow is the most common problem found with duct systems. It can come not only from a duct system with high static pressure, but also can be caused by clogged air filters or dirty cooling coils. Low airflow is the leading cause of compressor failures. Low airflow will also cause comfort and efficiency problems. At Apple Heating we have the tools and the technical knowledge to measure static pressure in duct systems, and to know if a problem exists. We also know how to correct problems when found. If you are experiencing problems with comfort or high utility bills, you should have your ductwork evaluated by Apple Heating. And if you are considering a new furnace, heat pump or air conditioner, you owe it to yourself to get the high efficiency you pay for. Don't by a high efficiency piece of equipment and expect to get comfort and utility bill savings if your duct system can't perform. At Apple Heating the performance is guaranteed.