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Thoughts about Ductwork, Duct Sealing, Duct Rehabilitation and Duct Tape.

We do ductwork rehabilitation based on system performance testing. Our motto is, "If you don't test, you don't know." The chance is that the ductwork in your house is held together with duct tape. We all know that duct tape is great for any number of quick fixes (see the Duct Guys for a humorous look at duct tape in action). But duct tape really is not the best way to hold together ducts! When duct tape fails, ducts go bad. That's when you need rehab for your ductwork.

What is Duct Rehab?

Well sealed ductworkThink of your heating system like the engine and tires of your car. The best car motor (or house furnace) won't make the system go if the tires (or the ducts) don't hold air. A high performance furnace will be a big disappointment if it is connected to ductwork that is poorly designed and installed.

How to develop a Duct Rehab plan by finding out what you, the homeowner or tenant, expects from your heating and cooling system and identifying the things we can do to help the system meet those expectations.

Let's start with that magic word, comfort. Understand that tight ducts alone do not create comfort. Comfort is largely a function of delivering the right amount of air at the temperature necessary to meet the heating and cooling load of the building. A room that needs 200 cubic feet (cfm) per minute of air to maintain comfort and is only getting 50 cfm will still be uncomfortable after duct sealing. Room by room heat loss and heat gain are really the way to address the issue of comfort. Follow up with an air distribution plan for the house that identifies air flow desired for individual rooms and then make our guarantee that we will hit those air flows within plus or minus 10%.

What's so bad about leaky ducts?

The negative side effects of Duct Leakage include:

Energy Waste and Discomfort Duct leaks can increase heating and cooling costs by  25%-40%.
Occupants are uncomforable so they bump up the thermostat to compensate in heating mode or bump it down in cooling mode.
Peak Electrical Demand HVAC units operate more than if the ducts were tight causing excessive electrical consumption.
Combustion Appliance Operation Depressurization that starts with leaky ducts can backdraft combustion appliances.
HVAC System Life Leaky ducts can compromise your HVAC system. Increased movement of dirty or dusty air plugs filters, coils and blowers. The system works much too hard hindered in this way which can lead to repair costs or replacement of the unit.
Indoor Air Quality Return leaks in unconditioned space may draw pollutants into the home.
Return leaks in a garage may bring in: CO and other combusion byproducts, automobile exhaust, fumes from stored chemicals, pesticides and solvents.
Indoor Moisture Humid air may be drawn into the home increasing the potential for molds, mildews and mites.

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Delta-T, Inc. is a Northwest Energy Service Company This page was last updated on 18-Jun-2005

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