Why Would A Duct Be Open Tobthe Attic

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.

Why would a duct be open tobthe attic.

According to nrel researchers david roberts and jon winkler moving the ducts from a vented attic to a new location inside the conditioned space will reduce electricity used for cooling by 15 to 20 and will reduce the size of the needed air conditioning equipment by 0 5 to 1 ton. It s done this way because it s easier and cheaper to run a flex duct through a wide open space than to fit it through and around floor and wall framing. If you have ductwork in your crawl space the temperature of the duct will be the same as the temperature of the crawl space. Bends in the duct should be gradual to prevent the loss of air flow due to turbulence created as a result of the sudden change in direction.

I was up in the attic yesterday and noticed something about my return air duct that is strange. The remaining 2 tons of capacity is at least 1 5x oversized for the actual 1 load. The duct coming from the attic does not ring familiar with how the make up air has been handled in the homes i supervised. Those are valid reasons to do it so the real answer is to make the attic at least semi conditioned space.

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. Put it in an attic full of blown insulation and you re forcing it to work harder to vent its heat. Jack apr 27 14 at 14 11. It also makes maintenance and or modification easier.

This means that like an attic or unfinished basement you don t heat and cool it. Disruption of air flow at bends in open attic spaces usually occurs where 90 degree changes of direction are sharply installed or where there is only one support typically located at the bend itself. In addition to making the unit hard to get to for service high attic heat can trigger the. Sealing ducts in the attic the sun beats down mercilessly almost all year and heats up the roofs to 150 160 degrees or more and that heat radiates down into the attic where all the ducts are located and then radiates down through the ceiling and makes our homes more uncomfortable and we have to run our cooling more and more.

I live in a 3 story townhouse and my return air ducts for the 3rd floor run through the attic space.