AC is not working at the upper level


Old 07-16-01, 10:34 AM
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Recently I bought a home. I have an electrical AC unit. In the basement and at the ground level the air flows normally. But at the upper level, the air is flowing very, very slow or is not coming at all. What could be the problem and how and where should I call to fix it?

Thank you!
Old 07-16-01, 02:34 PM
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Talking no air up stair.

Hi, A rule of nature/physics. Hot air rises, cold air falls. You have to FORCE cold air to go up........Most multi-level homes have this problem.
First of all you need to have a return air duct somwhere up on that second floor, and it should be oversized by at least 1.25% - 1.5% of normal. This is where the heat is, and this heat needs to be FORCED back down to the coil so that it can be cooled.
You should also use over sized supply duct work as well. The top story of your house will produce 60-85% of the total heat gain. If the ductwork is already in place and not easily changed, may need to add some additional in-line fans to increase the CFM (airflow). If it is possible you may want to add more and larger ductwork going to the upstairs area. I have even seen houses that have seperate A/C on each floor. That works quite well. Other suggestions would be spot cooling with some "in the window" type A/C units to cover poor duct work, or inadequate sizing.
Hope this helps..............

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