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duct sizes for each of my rooms

5.5K views 3 replies 2 participants last post by  beenthere  
#1 ·
I used the calculator on this page.
http://efficientcomfort.net/jsp/ResDuct_Web.jsp

These are my room sizes,cfm and flex duct size for each room

kitchen 7x17 119 7
dining room 10x13 130 8
family room 14x12 168 8
master bedroom 14x11 154 8
bathroom 7x6 42 5
small bedroom 9x14 126 8
smallest bedroom12x8 96 7

Do these figures look right?

I looked at the Air Handler in my neighbors attic and they had 6 inch insulated flex duct going to each room.

Another neighbor had 5,6 and 7 inch insulated flex running to each of their rooms.

All the homes are semi attached brick homes and everyone has a 2.5 ton compressor and air handler. Some of the homes had 2 ton units but I heard they weren't cooling their homes sufficiently enough.

Thanks.

Slash
 
#4 ·
8" can tend to cause discomfort in a room by making a small area colder then the rest of the room. While the right register can help avoid this. its hard to get the right register, as it often ends up needing to be a single throw/direction register.
 
#3 ·
Thanks for the reply.
I was just reading on this link that .06 is a more realistic friction rate.
http://contractingbusiness.com/indoor_air_quality/cb_imp_44696/

The .06 friction rate increases the size of some of the ducts.

Unfortunately, I'll be running the ducts through 2nd floor closets and I'll only be able to put 1 duct in each of the first floor rooms.

Why do say best to avoid 8"flex?

Thanks again.

Slash
 
#2 ·
Your CFMs only total up to 835.

Best to avoid 8" flex, and to use either 2-7", or 1-6" and 1-7".

.1" FR is seldom the correct FR, and generally leads to high static pressure, and low air volume through the air handler/furnace.