i just built an addition on to the back of our home, the addition is real tight, r30, r19 in walls, double insulated doors and windows, low e. all under a 6' porch.
main house simple rectangle 1200 sq
addition simple 650 under air
manual j was done said 3.5 went with a 4 ton trane 15i vari speed air handler. florida east coast
the house is not cold enough and the addition will freeze you out. i dont think the conmpany did the duct calculations. from all the stuff i have researched i think the 2 ten inch flex ducts that feed the main house are undersized and should have been 12 inch.
the plenum coming out of the air handler is about 22" square 1.5 inch duct board then it goes to 16" flex for 5 feet then into a dist box about 2x2 ductboard, 2 10 inch ducts about 25 feet long go to the main house and the other 10" branches off to addition. the air handler is in the addition. now the stuff i think i know.
cfm 1600-1800 dont know for sure for a 4 ton trane
10 flex duct cfm 340 -15%for flex
so if i have 3 x 300 and i have a 7" from the plenum box going to the addition also(dont know why) which is i think 140 cfm so i think i have a 1000cfm system.
so my question is if i go to 12 inch flex to the main house which should be 600cfm will i get more cfm to the hot rooms, will i loose air volectiy? i have to reduce the addition air flow, i plan to add a damper to the addition 10 to help balance the system but with the vari speed i really dont know what will help...if you need picts or i just confused you please email <<<removed email>>>
i really apprecaite any info on this. thanks tony
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[Edited by jrbenny on 06-23-2006 at 04:57 PM]