no ducts on top floor of 3 floor house

[kingsingh]

I just installed a Carrier 58MVC and their 16 SEER heat pump. I am using the Infinity control that is mounted on the middle floor. My middle floor and basement cool perfect. However, if I go upstairs, I get cooked. Average is about 28C in each of the 3 bedrooms. Currently, my furnance is pushing about 1000 CFM through the ducts for both main and basement floor. This unit is capable of doing 1400 CFM. Here is what I am thinking of doing:

I have full access to the attic on the top floor. I was thinking of installing ducts in throught the attic to each of the rooms. Then, I was going to run a single line from outside down to the furnance in the basement. I am thinking going outside since I don't want to rip walls to get up to the attic. Once, I get this done, I am going to zone the upstairs using a Infinity Control zone control.

I would like people to comment on the pipe I need to install outside to get up to attic. What issues am I going to have?

P

[hangfirew8]

I just installed a Carrier 58MVC and their 16 SEER heat pump. I am using the Infinity control that is mounted on the middle floor. My middle floor and basement cool perfect. However, if I go upstairs, I get cooked. Average is about 28C in each of the 3 bedrooms. Currently, my furnance is pushing about 1000 CFM through the ducts for both main and basement floor. This unit is capable of doing 1400 CFM.

Are your ducts capable of 1400CFM?

Here is what I am thinking of doing:

I have full access to the attic on the top floor. I was thinking of installing ducts in throught the attic to each of the rooms. Then, I was going to run a single line from outside down to the furnance in the basement. I am thinking going outside since I don't want to rip walls to get up to the attic. Once, I get this done, I am going to zone the upstairs using a Infinity Control zone control.

What about returns? Isn't the best way to cool an upstairs is to also get hot air out, not just pump cool air in, which will immediately head downstairs?

I would like people to comment on the pipe I need to install outside to get up to attic. What issues am I going to have?
P

Condensation, picking up heat, cost, possible need of a permit since you are expanding the footprint of your house.

-HF

[beenthere]

First issue, is the outside duct will cost almost as much as opening the walls up.
It will cost you more to heat and cool that floor because the duct is outside.

[kingsingh]

Of course there will be insulation around the duct and I would build a box around it to seem it is part of the inside. I am thinking it may be cheaper to do the outside solution, than ripping out walls?

In the attic I was going to add a powered fan to suck out all the hot air.

P

[beenthere]

2" insulated duct is not cheap.
By the time you have the duct installed, and have a nice looking chaise built and painted around it. The opening and closing of the inside wall will have been cheaper.
Plus the permit fee. Outside chaise isn't something your going to hide from the inspecters or neighbors.

[kingsingh]

Of course there will be insulation around the duct and I would build a box around it to seem it is part of the inside. I am thinking it may be cheaper to do the outside solution, than ripping out walls?

In the attic I was going to add a powered fan to suck out all the hot air.

P

[kingsingh]

the other problem I have with going on the inside is that I might have many more bends to be able to get to the top. I don't think I can go straight up.

My furnance sits next the the outside wall. I was going to cut a hold and to straight up to the roof rafters. This should be about less than 20 feet up. Then, in the attic I can use whatever. I am sure less than 20 feet is not going to cost me a fortune. Also, this is near the back of the house and I am sure no one will notice it.

Comments?

[beenthere]

2 chaises in the house are cheaper then going outside.