Advice needed on quote for hvac replacement

srirambaraAugust 11, 2012

Hi everybody,

Firstly, a big thanks to all the contributors on this forum. I have learnt more here ( than anyplace on the nternet)based on member postings that has really helped me make my decision.

My house currently has a 3 and a 5 ton unit for downstairs and upstairs. The current units are about 20 years old with more than its share of repairs done to them. I finally decided to replace because I cannot get the a/c unit to cool below 80f, when the outside is @100f.

I have 2 additional issues, where I was told that the heat load for my master bedroom and the game room is pretty high and the current system needs some modifications. The game room is accessible for new ducting, so another vent is going to be added into it. The master bedroom is in the first floor, with no access, so zoning was suggested. The contractor seems ok( I am not the best judge of people and tend to trust too soon ! :)). The following is what has been suggested to me for a total charge of $19,000.

16 seer american standard equipment:�

3 ton




5 ton




Accuclean: afd245clfr000d

Honeywell UV system: UV100a1059

Attic tent: AT-2

Honeywell 6000 tstat: Th6220d5

2- additional returns

1- vsupply to game room

1 honeywell zoning system for master bedroom/master bath.

I was also told that the 3 ton unit does not have a variable blower and it would cost me $650 to upgrade to a variable blower setup.

Does all of this price estimates sound ok to the experts out here ?

Do you guys suggest any changes to equipment for better value for money?

Today the temps have been kind in the north Texas area. My a/c unit was able to get the temps to 77f. I am beginning to think that maybe I should kick this can down the road :)

Thanks in advance for your opinions

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What size living area is each zone?


    Bookmark   August 12, 2012 at 7:42AM
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Tigerdunes: zoning was suggested in the first floor, the 2 zones are 500 sqft and 1600 sqft.
What is the difference between variable speed and multi speed blower btw ? American standard lists most of its furnaces as multi speed and a couple as variable speed. Are the multiple speeds in a multi speed controlled by load/ thermostat or is manually set at the time of installation.
Thanks Sri

    Bookmark   August 12, 2012 at 10:26AM
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Has the contractor done a load calculation? The house must be very big in order to justify 8 tons of cooling. Most homes don't have sufficient duct work to support a 5 ton unit. The contractor needs to verify you have the duct work to support all the required air flow.

    Bookmark   August 12, 2012 at 11:17AM
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I also would want a load calc for each zone.

Again, what size is the living space for the three ton system and the 5 ton system?

Variable speed furnaces are multi stage heating with ramp up and ramp down blower profile. Biggest benefit is improved dehumidification in AC cooling mode. For best performance and to achieve VS furnace operational capability, they should have a true two stage thermostat. The model quoted is incorrect.

The sgl stage furnace has fixed speeds that are adjustable. The model quoted has a high efficient blower but is not var speed. A good furnace though depending on application.


    Bookmark   August 12, 2012 at 11:50AM
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The contractor that I quoted performed the most comprehensive load calculation . Again, I am no expert but, a layout of the house and each room was measured wrt orientation, sqft, size of duct, window sizes and whether it was interior or exterior wall. All of this was loaded up in a laptop and the output was " you have the right equipment".
The living area on the first floor is 2100 sqft and 2 nd floor is 1700 sqft. I am not sure if the duct work was " checked" but it was definitely given an all clear. The only insufficient duct was the game room duct, where replacement was suggested.
I think I will go ahead based on tiger dunes explanation and spring for the variable speed blower. What in your opinion would be a good thermostat for this setup ?
How would I request a load calc copy? Is it a software file or just numbers written down ?

    Bookmark   August 12, 2012 at 2:19PM
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The floor areas you have quoted and the size of the units make no sense. Are you sure these numbers are correct?

Get a print out of the load calcuation. It should state the number of BTUs for heating and cooling. Get the name of the software being used. I am doubtful of a Manual J calculation software application which prints out "you have the right equipment".

Are you going to get any other quotes? You should get at least three proposals for a project of this size.

    Bookmark   August 12, 2012 at 3:35PM
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The load calc should be printed out on the software letterhead both cooling and heating with design temperatures inside and out for each zone. The best software shows the load calc for each room in the zone.

Like the above post, I question the sizing particularly for the 5 ton zone.

If going var speed furnace for each system, I would want HW VP IAQ thermostat latest edition.


    Bookmark   August 12, 2012 at 3:52PM
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mike_home: I was implying that most contractors agreed that i have the right equipment and not that the software read "you have the right equipment" ... lol. I did receive more than 3 bids/proposals. The cost of the equipment was very similar in all 5/6 bids. The only difference was in the cost of the add-ons like "accu-clean" etc. The reason i was tending to choose the quoted contractor was the warranty aspect and lower cost of add-on equipment.

mike_home/tigerdunes: I will try and get my hands on the load calculations and share with you guys if/when available.

tigerdunes: I will inquire about your suggested thermostat wrt prices. Are there any more models you would like to recommend? North texans have been constantly bombarded with advertisements for "NEST - Learning Thermostat". what are your opinions on those? They seem super pricey, especially if i have to buy 3 of them :) I am surprised that the contractor will provide a thermostat that will not be able to utilize all the features of the equipment. Is this standard practice in this industry ?

Thanks a ton for all the responses.

    Bookmark   August 12, 2012 at 4:30PM
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"I am surprised that the contractor will provide a thermostat that will not be able to utilize all the features of the equipment. Is this standard practice in this industry ?"

It happens more than it should. There is no need to have a two stage furnace with the timer on the control board handling the staging of the heating. A pure waste. And why does this happen? Because many dealers take this shortcut to keep pricing down on unsuspecting homeowners. A true two stg thermostat will run in low stage and never go to high stage unless demand requires it.

The HW VP IAQ is a tried and true two stage thermostat that also has dehumidify on demand feature for AC cooling. This could be helpful for your N Tex location. There are other models like the HW VP IAQ. I just think this is the best for the money.


    Bookmark   August 12, 2012 at 5:04PM
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