Air Conditioning - architectural duct

I would like too know where can I find some idea about architectural duct in the basement on the web.


My wife does not want the regular square shape in my basement. I am planning too remove my attic duct one day and install new duct in my basement with the furnace

Have to ask WHY here? Why not keep it in the attic????Why in the basement????I dont know just what duct you mean. The only one that comes to mind is the spiral pipe we use in big jobs some time its oval or round. Most of the time this is made on the job. But you can buy small round spiral pipe from a wholesale company.

ED ;)

To answer you question Ed Imeduc

I live where is cold in the winter sometime –35c my system is 3 years old and this spring the dealer replace all the 6” flexible duct because I notice ice in it. He installs new flex with 3” insulations. This time it was guaranty but next time I will pay.

I thing there is too much different in temp in the attic .So if all my duct was in the basement I would not have that ice in the duct and it would last for ever.

But my problem is my wife doesn’t want to see the ductwork in the basement.

And now that they change all my duct I hear the air coming out of the diffuser and my blower is on low .I thing I will have too dump more air in the basement add 1-2 extra flex 6” I am sensitive too noise.

Water in the pipe in the attic???? Is this just the AC duct work for the home up there and you have other heat in the home????

ED :thinker:

I think you ran the fan switch in AUTO. If any warm moist air was in the duct it would freeze and a few short runs and it would build up a layer of iced condensate. :o Especially in the off cycle. Moisture would condense there if it was real cold like that I would think. Insulating the duct with 3" will slow the problem BUT I think you might have a humidity problem. If you have a humidifier you'll need to dam near shut it off when it gets below ZERO, or you will have the same thing happening inside your walls though you won't see it till it's too late :wall: , and the framing members require replacement from dry rot. If you look at a humidifier setting scale...as the temperature gets lower, so should the set point. Plugged dryer vents or leaking dryer vents, bathroom vents plugged with dust bunnies, toilet seat covers left open all contribute to humidity gain in a house, cooking and plain old respiration too believe it or not! :eek: ...Especially if the house is real tight. ...........................just a thought.. .

My fan is on 24/7 .

I have a thermopompe 2.5t carrier puron .The dealer told me to put more insolation on all the flex.

Try again . Just what do you have in the attic is it just the AC unit are do you also have heat in itfor the home???????

ED :D

Yes I do have heat in the attic. My completed system is thermopompe carrier 2.5 t and furnace in the attic has 5 k emergency electric heat with 9 x 6” flexible duct. The Fan is on 24/7 on low speed .I recently install a waterless p-trap from ez-trap.

I do heat and cool with the system almost all year round I have electric heat convectaire in all room but I use them when the temp outside go below –18c my thermopompe has a cut off at –18c

When the thermopompe stop working below –18c my electric 5k in the furnace kick in.

Here where it's -35 degC for nearly half the year, furnaces and a/c's in attics are a no no.
It is common to have attic and roof top installs in commercial jobs but it is also extremely rare to have humidifiers in commercial establishments as well.

I'm afraid you can't have it both ways.
Regardless of your wife not liking the look of ductwork, ducts, especially quiet ones, require volume.
The bigger the duct, the lower the velocity, the quieter it will be..

With GregH put it down in the basement and do the duct work with duct board. That will help kill the noise for you .
How about a drop ceiling after all the duct work is in. Make the wife happy.

I have electric heat convectaire in all room but I use them when the temp outside go below –18c my thermopompe has a cut off at –18c

I still think when you go to this convectaire for a time this is where the warm moist air gets in the cold duct there and turns to the water that you get the ice from.

ED ;)

Well I try to design my duct with velocities in mind and with them not higher than 600 F/min. then design the registers according to the engineered stats. that they offer. Using Hart and Cooley registers and grilles the have good stats that are easy to understand. Oh and they make a quality product too. OOps no advertizing sorry.

How do you calculate duct for an attic with flexible pipe for a low velocity of 600cfm or more .Wath is the max f/m a 6" roud adjustable difusser should have for very little noise? All the flex in the box was 25' long.

One more question to have a proper sizing done or manual d –j etc do you get it calculated by a dealer salesman or a engineering firm?