Is there an HVAC standard for minmum amount of air that comes out of a residential AC vent?

Question

The vents in my house do not appear to be pushing out that much air. The smaller rooms get cool with the doors shut. But overall it takes a long time to cool the house 1 degree (about 2.5 hours) My AC unit has been tested and is cooling properly, but I believe it isn't pushing out enough air to cool the house effectivly.

Answer 1

THERE IS a min CFM(cubic feet per minute) of
air flow: It's 400CFM per ton. 12,000btu's = 1 ton of cooling per hr.
I.E. A 3ton unit removes 36,000btu's an hr with around 1200CFM of air volume(400 x 3 [tons])
Make sure that ALL registers are open. Closing them does not save energy or money. Ck the filter and make sure that it is not dirty or too dense/thick.

Answer 2

If you're not getting enough air out, maybe you're not getting enough air in. It could be that you lack enough return air. There is no standard for residential CFM output because (unlike commercial buildings) specifications do not exist for home construction. Professionally designing an HVAC system costs money so builders rely on seat of the pants contractors to install bottom-dollar systems. Nonetheless, you should feel some rather obvious air movement at all your registers. You might want to verify that you have adequate ducts to handle the tonnage that you have. Call a local HVAC company and ask what they'll charge to do an assessment. Good luck.

Answer 3

To expand on what ric ozz said, and to also answer your question. Generally what is used in residental A/C calculations, is to figure .75 cfms per sq. ft. Therfore a 2,000 sq. ft. house would require 2,000 x .75 = 1500 cfms divided by 400 cfms per ton would be 3.75 tons of cooling. There are many other factors that figure into cooling load calculations, such as insulation, window and door sizes, the direction they are facing, and the area you live in. Maybe this will give you an idea of what you are looking for. Good Luck.

Answer 4

be sure your fan is running the correct way as a motor can be wired to run both ways. If you fan is running backwards you will get some air out but not the amount you should