Ac Ducts In Attic

The air ducts for a central hvac systems are typically located above a home in the attic or upper crawl space or underneath a home in the space between the foundation and the floor so you don t see them unless you have cause to replace them.

Ac ducts in attic. The duct insulation should include a vapor barrier cover. Reduce the humidity level around your air ducts. When hvac ducts are installed in a vented attic in a dry climate bury the ducts in attic insulation to protect them from temperature extremes in the unconditioned attic space. In last week s blog i discussed the practice of burying attic ducts in deep insulation.

Use metal flex or fiber board ducts that are insulated to code. Heaping insulation over the ducts is fine in dry climates but can cause condensation on the duct insulation jacket in humid climates. So if the thermostat is sitting at 74 degrees the air being pushed into the duct system is going to be right around 54 degrees. If ducts are located in a crawlspace underneath your house cover the soil to reduce moisture.

First water dripping off of your ducts and onto your insulation can cause the insulation to compress which decreases it s r value or ability to insulate. Put it in an attic full of blown insulation. If you have central heating and or air conditioning in your home the warm or cool air is delivered to each room through a system of connected ducts and vents. Why is this a problem.

By spraying closed cell foam on the ducts before burying them in attic insulation you prevent the condensation problem. An attic can get up to about 130 f in the summer and the conditioned air entering the ducts is about 55 f or so. If we take into consideration that on a hot summer day the attic where your ducts live can be as warm as 150 degrees that 90 100 difference in the temperature is what can cause the condensation to begin. If they are located in your attic be sure the area is properly insulated and any cracks or holes are sealed.

The doe s building america program recommends beds buried encapsulated ducts. So water is condensing on your ac ducts. In more cases than not a 3 ton ac with the ducts in the attic has a ton or so of load that s just from the location of the ducts in the attic and the associated duct gains leakage etc. When water condenses and drips into your attic or home it can cause a some serious secondary problems.

Install ductwork so that it is in direct contact with i e laying on the ceiling and or truss lower cords. Attics and heat the condenser in your air conditioner works hard to get rid of heat and pressurize refrigerant for the return trip through your house. The remaining 2 tons of capacity is at least 1 5x oversized for the actual 1 load.