Variable speed blower and heater efficiency

rsguerraAugust 1, 2007

I live in New Orleans (high humidity) and I'm about to choose an A/C and furnace for a new construction 2 story home using the new blown in foam insulation in the attic and walls. 2 questions:

1. I am going with two 2-ton 14 SEER Goodman a/c units but I need to choose between a variable speed blower or single speed. The v/s will cost an additional $1,000.

2. The heater/furnace is spec'd at a 95% A.F.U.E. unit. Is this high of and efficiency rating necesssary in my area?

Thanks.

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garyg

Why not go with a heat pump and use the gas as back-up to the heat pump on days when the outside temp is less than freezing? You get the same a/c but with cheap heat. Your climate is not that cold. What are your electric rates in New Orleans? If they're cheap, you can go electric back-up and eliminate the gas altogether.

I installed a 14 SEER Goodman heat pump last month. You want to make sure that the installer is giving you a thermo expansion valve (TXV) installed externally at the air handler. This is an option for Goodman and will be the best $55 that you will spend. If the installer tells you that the unit comes with a TXV, he is wrong. For a 2-ton unit, the part# is TX3N2. Along with the TXV, the installer needs to put in a hard start capacitor on the outside unit, Part# CSR-U-1 for about another $18. The TXV will ensure that you are getting the 14 SEER rating from the system at all times under all conditions. The hard start cap provides the extra starting power needed with a TXV.

The 14 SEER Goodman is a better choice than the 13 SEER because the 14 comes with a Copeland scroll compressor (favored in the industry) while the 13 has a reciprocating compressor.

As far as the variable speed vs 3-speed fan, the v/s is supposed to provide better de-humidification. I live in Baltimore, a humid area, but I chose the 3 speed fan motor. I like to run the fan in the summer, and the v/s only runs the fan at 30% of the low setting when in fan-only. A 3-speed motor is much cheaper to replace than the v/s after the 10 year warranty. This was my choice, the majority want the v/s.

One last note, the air handler for the 14 SEER is different than the air handler of the 13 SEER. Make sure the contractor doesn't mismatch them. V/S air handler for 14 SEER is AEPF303616A (rated at 15 SEER with a TXV), 3-speed air handler is ARUF193116A (rated at 14 SEER with a TXV). You get an extra SEER point with the v/s motor. This info is on Goodman's website, www.goodmanmfg.com, Product Specifications.

Best of luck.

    Bookmark   August 1, 2007 at 10:02PM
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garyg

The part#s that I gave you for the air handlers are for straight a/c or heat pumps. If you go with gas, the air handler will have a completely different part#. Also, the TXV part# that I provided is for an R22 refrigerant system. If you go with a R410A system, it will be different. The part# for the hard start cap is good.

    Bookmark   August 2, 2007 at 7:03AM
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tigerdunes

rsguerra

dual fuel or a gas furnace is overkill for NO area/climate.
I would go for a 15 SEER heat pump with vs air handler.
Definitely not a Goodman heat pump. Trane and AmStd condensers stand up better to a coastal environment.

IMO

    Bookmark   August 2, 2007 at 8:14AM
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