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Old 09-10-2013, 07:14 PM
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Putting ac-heat unit in a 1600 sq ft. house. Contractor originally said 3-ton unit. I said 5-ton. He now says 4-ton.

He claims 1-ton for every 400 sq ft. This is in L.A. Calif.,pretty mild temps for most of the year. What do you all say.
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Old 09-10-2013, 07:36 PM
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I have had great luck with www.alpinehomeair.com . They have a sizing program based on where you live, home type, and sq footage. Great customer service.
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Old 09-10-2013, 07:52 PM
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I don't know your climate or house construction, but I'm willing to bet closer to 3 ton than 5 ton.

600 to 800 sq ft per ton for new construction with up to 1200 sq ft per ton for super energy efficient houses (I've done it and it worked very well). There's a lot that goes into proper sizing. I would think that your building codes would require manual J heat gain.
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Old 09-10-2013, 08:04 PM
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2300sf home in Florida 5 ton here.
A lot of this equation depends on the heat load and R value of your home.
Is this a new build or a replacement.?
Lots of windows?


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Old 09-11-2013, 04:41 AM
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Originally Posted by wfowahoo View Post
Putting ac-heat unit in a 1600 sq ft. house. Contractor originally said 3-ton unit. I said 5-ton. He now says 4-ton.

He claims 1-ton for every 400 sq ft. This is in L.A. Calif.,pretty mild temps for most of the year. What do you all say.
Why are second guessing the professional?
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Old 09-11-2013, 05:18 AM
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Originally Posted by wfowahoo View Post
Putting ac-heat unit in a 1600 sq ft. house. Contractor originally said 3-ton unit. I said 5-ton. He now says 4-ton.

He claims 1-ton for every 400 sq ft. This is in L.A. Calif.,pretty mild temps for most of the year. What do you all say.
Find a new contractor. I do Manual J Heat Load Calculations every day. I used our Load Calc program and switched the city and state from Fort Myers, Fl to L.A., California.

I took a 1646 sqft Florida home where the front of the home faces north with most of the glass facing south for example. This home requires a 2 1/2 ton Ac system

Same home just changed the location. This home in California requires a 2 ton AC system.

FIND A NEW CONTRACTOR !
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Old 09-11-2013, 07:45 AM
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The contractor originally said three ton and that should be about right. Not sure why as a homeowner you would want to add that much unnecessary tonnage .
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Old 09-11-2013, 07:55 AM
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Too small and it will run contiuosly, a waist of energy. Too large and it will not run long enough to do its job of cooling and removing moisture. Get a second opinion from your electric company? or another HVAC company.

Bert
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Old 09-11-2013, 08:13 AM
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Spot on contact your power company they will have the knowledge about your area.
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Old 09-11-2013, 09:30 AM
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I think you are way off, unless your house is painted black and you leave the windows open in summer.

3 sounds about right. 5 sounds way, way too big and you'll probably regret it. Bigger is not better. You WANT your unit to run most of the day on your absolute hottest day of the year.

I have 3.5 ton in my 1700 ft. 60s Florida home, and it's just right. Your numbers will be different based on construction, insulation, etc etc.

What is more concerning is that your contractor didn't explain why 3 could be better than 5. A load calc would have been nice but I'm not surprised that step was skipped as it seems many "professionals" do a seat of the pants calculation.

Last edited by Flot; 09-12-2013 at 06:59 AM.
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Old 09-11-2013, 10:40 AM
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The problem with going to your electric company they base there decision on a Energy calculation not a Heat Load calculation, there is a huge difference between the two.
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Old 09-11-2013, 11:19 AM
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Originally Posted by bsh102 View Post
Find a new contractor. I do Manual J Heat Load Calculations every day. I used our Load Calc program and switched the city and state from Fort Myers, Fl to L.A., California.

I took a 1646 sqft Florida home where the front of the home faces north with most of the glass facing south for example. This home requires a 2 1/2 ton Ac system

Same home just changed the location. This home in California requires a 2 ton AC system.

FIND A NEW CONTRACTOR !
I don't doubt that you know more about this than I do, but how do you know he only needs two tons from what he has posted? I mean, he could have aluminum frame single pane windows, tall vaulted ceilings and R9 in the walls. That would require more than 2 tons methinks.
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Old 09-11-2013, 11:35 AM
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Originally Posted by bsh102 View Post
Find a new contractor. I do Manual J Heat Load Calculations every day. I used our Load Calc program and switched the city and state from Fort Myers, Fl to L.A., California.

I took a 1646 sqft Florida home where the front of the home faces north with most of the glass facing south for example. This home requires a 2 1/2 ton Ac system

Same home just changed the location. This home in California requires a 2 ton AC system.

FIND A NEW CONTRACTOR !

I say the contractor needs to find a new customer.

What I see here is the contractor knows that 3 ton is adequate. The contractor came across a customer that obviosuly knows more than they do. Rather than tell the customer they are "wrong" or an "idiot", the contractor opted for the tactful way and compromised at 4 ton, even though they know it is probably a bit over sized.

It is akin to a customer telling me how many squares their roof really is, after I told them.

So, to the contractor

FIND A NEW CUSTOMER!
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Old 09-11-2013, 01:47 PM
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Originally Posted by Jersus View Post
I say the contractor needs to find a new customer.

What I see here is the contractor knows that 3 ton is adequate. The contractor came across a customer that obviosuly knows more than they do. Rather than tell the customer they are "wrong" or an "idiot", the contractor opted for the tactful way and compromised at 4 ton, even though they know it is probably a bit over sized.

It is akin to a customer telling me how many squares their roof really is, after I told them.

So, to the contractor

FIND A NEW CUSTOMER!
Are you still mad at me ??
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Old 09-11-2013, 01:52 PM
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Originally Posted by mduran View Post
Are you still mad at me ??
I do not take internet forums seriously enough to get mad.
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Old 09-11-2013, 04:13 PM
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Originally Posted by houtxfisher View Post
I don't doubt that you know more about this than I do, but how do you know he only needs two tons from what he has posted? I mean, he could have aluminum frame single pane windows, tall vaulted ceilings and R9 in the walls. That would require more than 2 tons methinks.
Because he is building a new home in California. Pull up the building codes in California, they are far more tighter than in Florida.

The home I used for a reference in SW Florida was just what you described.
Single pane hung windows, r-3 concrete walls, r-30 ceiling, had a total of 228 sqft of glass.

I was also showing a home in LA, California requires less cooling than in sW Florida to maintain the same living conditions.
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Old 09-11-2013, 05:00 PM
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Originally Posted by bsh102 View Post
Find a new contractor. I do Manual J Heat Load Calculations every day. I used our Load Calc program and switched the city and state from Fort Myers, Fl to L.A., California.

I took a 1646 sqft Florida home where the front of the home faces north with most of the glass facing south for example. This home requires a 2 1/2 ton Ac system

Same home just changed the location. This home in California requires a 2 ton AC system.

FIND A NEW CONTRACTOR !
^^^ This.

(Insulation, windows, doors, etc. also factor in. But I can tell you, NO WAY you need 5 tons. Not a chance.)

Be sure and thank bsh for the help.
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Old 09-11-2013, 05:58 PM
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Never oversize a AC load.
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Old 09-11-2013, 08:27 PM
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Wow, this thread is so full of wrong, inaccurate and misleading information, it should be deleted. Luckily, a few posters offered some good info, don't know how to OP could sort through it. I agree, why does the OP think he knows more than a licensed contractor. It should be mandatory that a heat gain be calculated by a professional. BTW, why does one poster think it's new construction? Did the OP say it was new construction?
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Old 09-12-2013, 01:44 AM
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Originally Posted by Jersus View Post
I do not take internet forums seriously enough to get mad.
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