T
ThomasB
Guest
Hello,
I have a residential renovation that has expanded the floor area from 1000 gross to 1263 gross Sq. Ft. and needs to have the duct work expanded.
The original house had 182.6 Sq. In. of supply and 152 Sq. In. of returning air duct. Of that 128 Sq. In. of supply goes to the bedrooms and bath and is not changing. Rooms excluding bath and kitchen have individual returns.
The longest existing supply duct run is 14 + feet. The longest new supply duct run is 18 1/2 ft.
New returns are already in place and provide 202 Sq. In area.
I am estimating the new supply duct dimensions, in relation to the old area with a desire to have the new duct going to the living, dining and kitchen provide more air than previously. Kitchen gets a 3.5x10 and the living and dining rooms got a trunk line of 10x13 (165 Sq. In.).
With a furnace that provides 1210 CFM what will be the impact of having a greater supply area in relation to return than previously (I get a proportion of 1.2 old versus 1.45 new)? To my best understanding that creates lower air velocity in the supply.
I also have some idea that the supply duct shouldn't be larger than the furnace opening anyway, is that true?
How does the duct size impact the systems efficiency?
Has this system been built into a problem?
Thank you.
I have a residential renovation that has expanded the floor area from 1000 gross to 1263 gross Sq. Ft. and needs to have the duct work expanded.
The original house had 182.6 Sq. In. of supply and 152 Sq. In. of returning air duct. Of that 128 Sq. In. of supply goes to the bedrooms and bath and is not changing. Rooms excluding bath and kitchen have individual returns.
The longest existing supply duct run is 14 + feet. The longest new supply duct run is 18 1/2 ft.
New returns are already in place and provide 202 Sq. In area.
I am estimating the new supply duct dimensions, in relation to the old area with a desire to have the new duct going to the living, dining and kitchen provide more air than previously. Kitchen gets a 3.5x10 and the living and dining rooms got a trunk line of 10x13 (165 Sq. In.).
With a furnace that provides 1210 CFM what will be the impact of having a greater supply area in relation to return than previously (I get a proportion of 1.2 old versus 1.45 new)? To my best understanding that creates lower air velocity in the supply.
I also have some idea that the supply duct shouldn't be larger than the furnace opening anyway, is that true?
How does the duct size impact the systems efficiency?
Has this system been built into a problem?
Thank you.