Installing new system, need input


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Old 09-15-11, 07:27 PM
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Installing new system, need input

Located in the Cape May, NJ area. I have had two estimates so far, expect to get more. Situation is basically an all new install in an old home. The old system is in crawl space with ducts there also. VERY inconvenient and you have to rip the floor up to get it in or out. Currently have no AC. The home is one story about 1200 sq feet.

First Estimate was Payne and gave few details. The whole estimate was about 2 sentences. This one proposes putting it in an unheated attic with ducts there also. Payne 90% with 3.5 ton, 13 seer - $7800, with 16 seer, $8300

Second estimate was more detailed. It was either a Bryant 340AAV036080 80K BTU 92.5% AFUE, CNPVP042ATA 42K BTU evaporator, 113ANW036 13 seer 36K BTU compressor
for $7725

or a Bryant 353BAV036080 80K BTU 2 stage 92.5% AFUE with the same air conditioner equipment for $8,550

In addition the second estimate offered a 538A036 Side discharge compressor SEER 15 for an additional $1350 - This was because of my concern about the space taken up by the larger square unit in the side yard.

I am interested in comments on these quotes. Keep in mind this includes a complete ducting system installation.

Neither estimate includes the high voltage wiring for the outside compressor. I think I can handle that. DP 30A breaker in panel and disconnect mounted on wall where the compressor goes.

One concern I have is the size of the AC. I currently cool this house reasonably well with two window units. One is about 10K BTU and the other is 7K BTU. 36K BTU sounds like overkill to me. He did do a heating load estimate. In he I see he set an inside summer temperature of 70 Deg. I would never set it that low in the summer. More like 76 Deg. This is also a shore property and temperature over 90 Deg are rare. The humidity can be high though.

Thoughts?
 
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Old 09-15-11, 08:44 PM
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You need to run a Manual J heating & cooling load calculation. Homeowners can download one of the best I've used from here: HVAC Software, HVAC-Calc for Heat Loss, Heat Load Calculations

The cost is $49 for your own home & will be the best $49 you'll spend on the whole project.
 
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Old 09-15-11, 09:55 PM
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I understand the whole gain/loss calculation thing and understand its importance but in an established home with years of heating and cooling experience sometimes you need to use your gut and common sense. I think I need to go back to the installer that gave me the estimate. He did a complete evaluation, measuring everything. He seems to have been extremely conservative though setting the inside temperature at 70 Deg and outside 95 Deg. I would never put the inside lower than about 76 and the outside is very rarely above 90. So that is about a 10 Deg differential difference. I suppose that would make quite a difference in the calculations.

While I am interested in sizing I am more curious about thoughts on the equipment suggested and the overall price for the project.
 
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Old 09-17-11, 07:33 AM
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He is sizing properly. The unit must be able to keep up if you ever sell the home or something along those lines happens.
While I am interested in sizing I am more curious about thoughts on the equipment suggested and the overall price for the project.
This is really not the forum for that. This is a do it yourself forum. We are not here to discuss pricing or equipment brands. Main thing we can tell you is get at least 3 quotes from reputable contractors. Also, that equipment brand does not matter so much as how it is installed. And to remember you get what you pay for.
 
 

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