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3900 sq ft - 3 ton unit


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Somehow it doesn't seem like enough!

3,900 square feet on three floors.

3 ton unit.

Your thoughts?

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In case you can't read it the Bryant model # is:

213CNA036-B

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Manufactured by Carrier under the Bryant label. Carrier numbers are the most troublesome to decode.

I suspect it's a 5 ton. If the vapor line is a 7/8th, it's not a 3 ton. 7/8th begins at 3 1/2 ton.

Marc

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Somehow it doesn't seem like enough!

3,900 square feet on three floors.

3 ton unit.

Your thoughts?

Click to Enlarge
tn_201442922637_B4U001.jpg

54.34 KB

Click to Enlarge
tn_201442922717_B4U054.jpg

72.12 KB

Click to Enlarge
tn_201442922756_B4U055.jpg

52.22 KB

In case you can't read it the Bryant model # is:

213CNA036-B

It appears to be 3 tons. That sound does not look like 3900 sf. By three floors, I assume you are including the basement. Even if you take 1/3 of the SF away 3 tons is small, unless the house is very energy efficient.

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What kind of insulation package was used in the home's construction?

Spray foam by any chance?

That might cause a mechanical adjustment for the A/C.

I recently saw a new home down here that had been foamed throughout during construction with the foam at the bottom of roof decking. They had a bit smaller A/C unit in there as well.

I'd have to dig to find the file on the site as I can't recall #'s off the top of my head.

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I shopped online for a Hi-Eff Bryant 4 ton...max Breaker size is 40. Erby's is 35...it's likely a 3 ton after all.

I'd still call a local Bryant or Carrier dealer to be sure. If it's suspected to be undersized, that's important for the buyer to know.

Is the site up in the mountains?

Marc

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It might be OK. All studies of the last 20 years show that equipment is routinely oversized, and a lot of those ballparking gambits we use (1 ton per 700-900 sf, etc.) are outdated.

It's easy enough to ask for the calcs.

OTOH, 3 ton Carriers are one of those container items; they ship thousands of containers of 3 ton units, everyone stocks the crap out of them, and one sells what one has in stock.

I'd get the calcs.

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Erby,

As you know a lot of aspects go into sizing a HVAC unit. I am presently air conditioning my 4100 sq ft 2 floor house in south central Texas mostly with a 3 ton unit. I do have a 4 ton unit that is zoned that comes on very sparingly. As others have said the insulation, the infiltration rate, the sensible/latent split and other aspects must be considered. Have a reputable HVAC contractor run a load calculation. As least then you will have a recognized number.

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Report said:

===

I note that exact air conditioner sizing requires calculations that go way beyond the scope of a visual home inspection. However, this appears to be a 3 ton unit. A general rule of thumb for this area is 500 to 700 square feet per ton. Paul told me that the square footage of this house is about 3,900 square feet. Unless there's a heck of an insulation package this unit may not be large enough to properly cool the house. Ask the builder for the calculations that were used to determine the size of unit needed for this house. If you have a problem during the heat this summer, ask the builder to come back and fix it.

===

I just don't see that Bryant heat pump pushing cold air from the basement up to the second floor very well. We'll see.

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