Installing a new attic mounted A/C system

Old 08-06-16, 08:06 AM
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Installing a new attic mounted A/C system

I'm looking to install a central a/c system in my home and have a few preliminary questions and need some guidance.

First, here's a little background on the home.

- located in central NY which has relatively short summers and fairly long winters
- L shaped ranch house with about 1,900 sf
- heating and hot water is provided with a 4 year old oil fired Buderus boiler and boiler mate. The heat is supplied through baseboard units
- the attic is accessed through an opening in the garage ceiling and covers the entire footprint of the house
- house was built in early 70's and has 3 1/2" insulation in the walls a 12" in the attic

My current thinking is:

- I do not think I want to install a mini-split system because my wife and I could not live with the addition of the power and coolant lines running on the outside of the house. Plus, I believe it would require a number of outside units in order to provide adequate cooling to all parts of the house and the cost might be close to the cost of a centralized system

- Based on my limited knowledge I'm thinking an air handler type system mounted in the attic makes the most sense as much more aesthetically pleasing and more effective in providing cooling to all parts of the house

My initial questions are:

1. Based on what I already stated does a centralized a/c system make the most sense?

2. Are there other a/c system types or designs I should consider that would work well in my houses configuration?

3. What might the approximate cost range be to install a system in the attic?

4. Am I likely to save money with the total installation if I have it done in the fall or early winter when its cooler in the attic for the workers and new installs might be a little slower

5. I've read some comments on the internet by HVAC contractors stating they would never consider putting a a/c system in a hot attic. Isn't it done all the time in the southern and western states where there are no basements?

6. What's the best way to find experienced and well qualified contractors to get estimates from and perform the install?

I would appreciate your thoughts, comments and suggestions

Thank you

Old 08-06-16, 11:17 AM
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1. Yes
2. You really only have 2 choices Mini split or central.
3. It varies across the the country but you can expect from 3K to 5K.
4. Vey little price difference.
5. I always avoid putting A/H's in the attic.
6. Ask family and friends.
Old 08-06-16, 11:42 AM
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Central is likely your best bet. With them you have choice of conventional system with low velocity large ducts or one of the high velocity small duct systems. Unico and Spacepak are two examples of the latter. They are really easy to retrofit into an attic.

I have found that, here in Ohio at least, the installers simply won't do new installs that involve attic work during the summer.

Attic is not ideal place for the A/H, but as you's done all the time in other parts of the country.
Old 08-06-16, 12:12 PM
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they would never consider putting a a/c system in a hot attic. Isn't it done all the time in the southern and western states where there are no basements?
It is done here in Houston where I live all the time. Probably 90% of the time. About the only exceptions would be mobile homes and very old houses that originally had furnaces only when built. Those would mostly be in a closet. Probably usually hotter in our attics then in yours.
Old 08-12-16, 02:27 PM
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I'm starting to get estimates from HVAC contractors and one item that varies from one contractor to the next is whether they use rigid pipe for the supply lines from the air handler to the diffusers or flexible pipe.

One contractor that installs only rigid metal says the flexible pipe will ultimately sag and it could restrict the flow of air especially where it makes the turn to the diffuser.

Does anyone have an opinion or thoughts about rigid pipe verses flexible pipe for supply lines?

Btw, the estimates for this installation looks like its going to fall between $12,000-$13,000.

Given all that needs to be done, does that sound high or about right?

FYI, I had gotten a quote to do this in 1980 when we first bought the house and the estimate then was $5,000-$6,000 so with inflation I'm not terribly surprised at the price today.

I would appreciate your thoughts and comments.

Thank you
Old 08-15-16, 08:20 AM
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$12-13K sounds a little on the high side but not way out of line considering the install is an attic. Metal duct certainly has its advantages IF all seams are well sealed. I don't have a problem with flex, again, IF it is installed right. The silver mylar jacketed flex holds up a lot better than the other types of flex. Sagging can be prevented by using a metal elbow at the ceiling outlet connection.
In my area the ducting must be pressure tested upon completion before the inspector will sign off on the installation.

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