Ductwork may be the most overlooked part of an HVAC system. Hot spots, cool spots and high energy bills can all be because of ducts that don’t do what they should. Comprehensive testing has been performed on hundreds of homes by researchers and utilities to measure the actual operating efficiency of air condition and heating systems after installation. This testing has shown that most systems are operating with efficiency losses between 15% and 50%.
Most Homes Have Ductwork Problems
Most often, the problems are a result of poorly designed duct systems that do not allow for proper air distribution. The results of the testing show that:
• Air flow is typically well below the 400 cubic feet per minute per ton that the equipment was rated at during SEER testing, making the system less efficient than it should be.
• Air duct leakage is commonly found to be above 25%. Simply sealing the ductwork properly would result in a much more efficient system.
• Most homes have undersized return ducts and grilles.
• High fan pressures from improper duct installation and poor duct designs are the norm. This could lead to faster wear and tear on your HVAC System.
The types of deficiencies mentioned above dramatically lower the SEER and capacity of the system. The system is not able to deliver the cooling of which it is capable. A 14 SEER air conditioning unit will operate as low as a 9 or 10 SEER device when the air delivery system is not working correctly. In short, you don’t get the comfort or the efficiency you are paying for. Our experience has shown that significant air duct leakage is the norm rather than the exception. It is routine to find air conditioning systems that are drawing hot and unfiltered attic air into the home causing excessive utility costs and poor indoor air quality. A 20% duct leakage in a 5-ton air conditioning system is equivalent to wasting a ton of air conditioning or in dollars and cents, about $500 per year. Multiply that times the life span of 15 years and the increased cost are substantial. Quality really does matter.
Common Duct Problems
Because ducts are hidden away and only carry conditioned air, most people forget about the ducts as a possible reason for comfort problems. Here are a few things to look for to help determine if you need your ducts inspected or some repair work done.
- Poor airflow at either an intake vent or register. If there is little suction at an air return or intake grille, the first step would be to check to make sure the air filter isn’t clogged. If it isn’t then you could have a serious problem because your system will not be getting enough air and the fan in your air handler is probably working way too hard. When there isn’t much airflow coming out of a register there is also some type of problem. It may be as simple as a closed damper on a duct, but could also indicate that there is a large leak, clog, kink or supply line that is not large enough.
- Dust gathering at your air vents can be an indication that air is getting into the system from inside the attic, rather than through the sealed system. Of course, you’ll want to check to make sure your air filter is in place and not so clogged that dust is traveling through the whole system. Sometimes improperly installed ducts can come loose from distribution points in the attic or animals can chew holes in flexible ductwork. If you have dust collecting, it is time to have your ducts inspected.
- Hot spots and cold spots are another indication that airflow is not as good as it should be. In some cases, the airflow through the duct to a room may be fine, but it still isn’t enough to keep that room a comfortable temperature. In this case, adding another vent may be the right solution.
- Insects mysteriously appearing in your home. Wasps are particularly good at finding their way into your home if the ductwork isn’t sealed completely. In one case, a customer couldn’t figure out how the wasps kept getting into their living room until they saw one fly back up and into the ductwork. An inspection of the ductwork revealed that the ducts were improperly attached to a distribution box in the attic. The wasps had wriggled their way into the attic, then found the opening in the ductwork and worked their way into the living area of the home.
- Unpleasant smells coming from your ducts. You might notice a bit of an odor when the heat kicks in for the first time during the season or maybe even when the air conditioning is turned on in the spring. However, if you regularly have musty or unpleasant odors coming from your vents, there could be a bigger problem in your ducts. Mold has been known to grow in ductwork and occasionally animals have been found nesting in there. Hopefully, you won’t have to experience this unpleasant problem.
- Duct insulation minimizes the heat gain or loss as the air passes thorough attic areas. It also prevents moisture or sweating of ductwork that can cause growth of mold and bacteria. If there is no insulation on the ductwork or it has gotten old and deteriorated, then you lose efficiency. The American Society of Heating, Refrigerating and Air-Conditioning Engineers considers the life expectancy of ductwork to be around 30 years. Depending on the conditions and location of the ductwork, it could be less. Some types of flexible ductwork that were installed in homes 10-20 years ago were not designed for high heat environments like attics. Most of your ductwork, whether flexible or rigid, should have a shiny metallic appearance on the outside. If it is gray in color, we suggest having your ducts inspected to be sure they have not deteriorated due to heat.
- Sealing the duct system so there is no air leakage is important. A properly sealed duct system minimizes power consumption and prevents unfiltered attic air from being drawn into the home. Studies show that 20-30% of the air in a typical home is lost through holes and connection leaks in your ducts (Energy Star). Sealing the duct system helps improve comfort, improves indoor air quality, prevents hazardous conditions like backdrafting, and saves money by making your system more efficient. The right way to seal ducts is to use mastic, because it provides a better and longer lasting seal.
Live in the Charlotte area and have one of the above problems with your ductwork? We can help make your home more comfortable.