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Charlie
Can't cool one upstairs bedroom

We just put in a new furnace and AC. Our condo has 2100 sq. ft. There are three bedrooms upstairs. Two of the bedrooms cool/heat very well. The third bedroom is over the garage. We had a new garage door R-17 installed, 18" of blown in insulation in attic over bedroom and sealed inside and outside cracks. The temperature remains 12 degrees hotter and 15 degrees cooler than the other bedrooms. This bedroom has a cold air return and no vaulted ceilings. The other 2 bedrooms have vaulted ceilings. Three different HVAC companies have told us the only thing to do is put in another heating/AC unit for this bedroom only. There are Andersen casement windows and Condo Assn. won't allow window units.

Can you help please?

Bob Gabrilson
Re: Can't cool one upstairs bedroom
Charlie Shaw wrote:

We just put in a new furnace and AC. Our condo has 2100 sq. ft. There are three bedrooms upstairs. Two of the bedrooms cool/heat very well. The third bedroom is over the garage. We had a new garage door R-17 installed, 18" of blown in insulation in attic over bedroom and sealed inside and outside cracks. The temperature remains 12 degrees hotter and 15 degrees cooler than the other bedrooms. This bedroom has a cold air return and no vaulted ceilings. The other 2 bedrooms have vaulted ceilings. Three different HVAC companies have told us the only thing to do is put in another heating/AC unit for this bedroom only. There are Andersen casement windows and Condo Assn. won't allow window units.

Can you help please?

Do you feel any air coming from the diffuser? I assume the supply is in the ceiling? You could possibly zone the system.

Charlie
Re: Can't cool one upstairs bedroom

There is a small amount of air coming from the diffuser, not as much as the other two bedrooms. Zoning the system sounds great and expensive. How do i go about that? None of the HVAC contractors even suggested such?

Bob Gabrilson
Re: Can't cool one upstairs bedroom
Charlie Shaw wrote:

There is a small amount of air coming from the diffuser, not as much as the other two bedrooms. Zoning the system sounds great and expensive. How do i go about that? None of the HVAC contractors even suggested such?

I don't like to hear that it's blowing "just a little". When we do "bonus rooms" over the garage, we make sure to install extra supplies or increase the diameter or the supply pipe.
Are your diffusers in the ceiling? If so, you have a "up" duct to the attic. This makes it easier to add zoning and possibly to add another supply.

Charlie
Re: Can't cool one upstairs bedroom

The diffusers are in the ceiling and I do have up ducts. Do HVAC companies usually do zonal heating/cooling? What kind of price should I expect. Why was this never explained to me by these companies? Don't they know? Is this usually in the expertise of much larger companies or industrial ones?

How about you coming down from Quad cities and doing this?

Sten
Re: Can't cool one upstairs bedroom

Zoning is good but it probably just needs to be balanced

Bob Gabrilson
Re: Can't cool one upstairs bedroom
Charlie Shaw wrote:

The diffusers are in the ceiling and I do have up ducts. Do HVAC companies usually do zonal heating/cooling? What kind of price should I expect. Why was this never explained to me by these companies? Don't they know? Is this usually in the expertise of much larger companies or industrial ones?

How about you coming down from Quad cities and doing this?

I think companies don't do zoning simply because they haven't tried to expand their expertise. They will "zone" with equipment which will usually result in oversizing.
I have a 3 zones (3 thermostats) system in my 2,250 sq. ft. home and it works great. It'll cost about $3,100.00. How far from the Q.C. are you?

Bob Gabrilson
Re: Can't cool one upstairs bedroom

Charlie,
I re-read your post. You said that your system was new. Did you have the same problem with the old system? Does your condo share one wall or two? Your A/C may be oversized to make matters worse.

Charlie
Re: Can't cool one upstairs bedroom

Thanks for your help Bob. The same problem occurred with the old system. When the new one was installed = no one EVER mentioned zoning! When I complained about the low air flow I was given the response that there was nothing they could do except put in a separate unit for that bedroom.

I'm afraid that I'm too far away from you Bob ....I live in Cincinnati. Do you have any contacts here that I might avail myself of?

Bob Gabrilson
Re: Can't cool one upstairs bedroom

The same goes on here, the heating/AC people do the bare minimum. I don't know anyone there to direct you to, sorry. First, I would find out if a second (supply) diffuser can be installed to that room. Or maybe the existing supply could be enlarged. This probably needs to be done before zoning will help. Google Arzel Zoning and find some one in your area. Anyone that has done zoning "should" know something about ductwork. Good luck.
P.S. Make sure they check the return air as well.

rdesigns
Re: Can't cool one upstairs bedroom

The bonus room duct run is probably the longest run in the duct system, which means other register/diffusers will get almost all the air unless the system had balancing dampers and was properly balanced, which it obviously was not.

A fairly simple and cheap approach would be to install an in-line booster fan in the branch duct that supplies the bonus room since it sounds like you have attic access to the branch duct. You would want to install it as near as possible to the point where the branch duct takes off from the trunk line.

The biggest challenge will be the electrical connections and controls. Ideally, the booster fan would be interlocked to run anytime the furnace blower runs.

Also, while you're in the attic, do a thorough check to ensure that the ducts don't leak air, and that they are well insulated with a vapor barrier on the outer surface.

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