Doug, The Ductwork Detective®
RCD Corporation’s official mascot wants you to save energy and improve indoor air quality by sealing leaking air ducts, plenums, and registers with RCD air duct sealants and mastics. Did you know that coating exterior surfaces exposed to solar radiation with bright white #15 Weather Barrier Coating® reduces heat gain of the coated surface by reflecting solar radiation back into space, similar to the polar ice sheets? Reducing the heat gain of roofs and buildings lowers the demand for conditioned air which saves electricity (money) and reduces carbon emissions by burning less fuel to create electricity.
Frequently Asked Questions
Q. Why is sealing air ducts important?
A. Leaking air ducts often account for 10 to 30 percent of total heating and cooling costs. Leaky ducts can waste hundreds of dollars annually. The health and comfort of the occupants is the most important reason to seal air ducts. Ducts are usually located in the attic, basement, or crawl space. Many times the air handler is located in the garage. If the ducts leak in these areas contaminated air can be drawn into the living areas of the home. Vermin may also take up residence in air ducts that have openings that leads to animal waste inside the air ducts.
Q. How do duct leaks affect heating and cooling equipment?
A. If the duct leakage is 20% of the total air flow, the efficiency of the heating and cooling system can drop by 50%. Duct leakage lowers the heating and cooling capacity, shortens the equipment life, and increases monthly cost since the system runs more than it should to achieve a desired comfort level. Many comfort complaints in homes are due to air duct failures.
Q. How do I know if my air ducts are leaking?
A. Visually check your air ducts and air handler looking for obvious issues like disconnected ducts. Energy codes require that all joints in the system be sealed. Having a HVAC or Weatherization Contractor perform a “Blower Door Test” on your home will determine the amount of leakage along with the leak locations.
Q. Why is duct leakage so common?
A. Many times the duct connections are simply not sealed. There is also a problem with poor quality materials being used to seal ducts. Experts prefer sealing ducts with mastic. Mastic is a thick paste which can be used on all duct materials and provides a permanent seal.
Q. Are certain types of ducts more airtight?
A. Studies show that all types of air ducts can have problems with air leakage. Water-based air duct sealants seal metal, flexible, and rigid fiberglass duct board. Try to avoid using framing (such as panned returns) for air ducts these are usually more difficult to seal properly.
Q. If the ducts are insulated, do they need to be sealed?
A. Yes. Insulation does not stop air leaks. Look for dirt streaks in duct insulation, that’s a sign that air has
been leaking from the ducts.
Q. What are the most important areas to seal?
A. Seal in this order:
High Priority Leaks
• Disconnected components
• Connections between air handling unit and the
• plenums
• All seams in the air handling units, plenums,
• takeoffs, boots, and other connections, especially
• site-built items
Moderate Priority Leaks
• Joints between sections of branch duct work
Low Priority Leaks
• Longitudinal seams in round metal duct work
Volume and Weight Answers
How many fluid ounces in a cup? 8 fluid ounces
How many cups in a quart? 4 cups
How many quarts in a gallon? 4 quarts
How many fluid ounces in a gallon? 128 fluid ounces.
How many ounces in a pound? 16 ounces
How many grams in a ounce? 28.34952 grams