Need help deciding on new air conditioner

10 years ago

It's hot and humid here in Houston and my upstairs AC has multiple leaks, so a replacement is needed. Here is what is being suggested.

1. Condenser - Lennox, model no. XC17030
2. Evaporator Coil - Lennox, model no. CH3331A
3. Furnace - Lennox, model no. SL280UH070V36A
4. Thermostat-Lennox Wi-fi color digital thermostat

Another question, so I need two stage compressor and variable speed drive/blower/fan to help with the humidity which is oppressive. To get the house cool we have to set the temp lower and it feels clammy to me, especially during the hottest days.

I am concerned that none of the companies that came out to bid a replacement suggested a Manual J or Manual D (we have mult. temperature differences between rooms.

I only know enough about HVAC to be dangerous hopefully those of you with more knowledge will come to my aid.

Chris

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Comments (9)

tigerdunes
10 years ago
What size system are you replacing?

What size is your home?

Post model number of thermostat quoted.

Clamminess suggest dehumidification issues. Have you discussed this issue with your dealer? What are typical run times for AC cooling?

Post back.

IMO
taylor8810
Original Author
10 years ago
Tigerdunes,

I am having a 2.5 tom replaced.
The home is 3400 sq. ft. but this AC is for the upstairs only, I'm guessing 12-1400 sq. ft.
The thermostat is icomfort Wi-FiÃÂ® Touchscreen Thermostat
Include Merv 11 air filtration system
I have discussed the humidity with the HVAC company. I have no idea of the typical run tines, but it is NOT cyclling on and off. The reason for the replacement is multiple leaks in the condenser. They added 5 lbs. of freon to tide us over, to be recovered and credited back to up with new installation. Is there any other information I can provide. Thank you and this forum for any assistance. I am very grateful there is a place to go for people that are HVAC challanged (idiots like me).
Christine
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taylor8810
Original Author
10 years ago
Someone from the HVAC company is coming out to do a load workup whatever that is. How does that affect my decision? Desperate for more advice. Please
taylor8810
Original Author
10 years ago
Oh, is there a problem with the AC being on the more efficient end and the furnace with the blower at 80%. Reminder I am in Houston, very mild winters and horrendous summer humidity and head. Since the blower is part of the furnace and it has variable speed, is the blower less efficient than the blower in a more efficient furnace. Obviously don't need much heat but since the blower will be on much of the time, drawing electricity, that is a concern. Or do I not need to worry?
weedmeister
10 years ago
"load workup" might be a ManualJ. You would want this. while they are there, discuss the uneven temperature problems you mentioned.

I think you would want to look into a thermostat that can do Dehumidify on Demand. On a 2-stage compressor, it will hold it in the first stage for humidity removal. On the proper furnace blower, it will 'communicate' with the furnace and hold the blower to a low speed. Otherwise, with a variable speed unit that starts with a low speed and slowly increases, it will also do well at removing humidity.
taylor8810
Original Author
9 years ago
Weedmeister,
Thanks,

They just did a load calculation, I specifically said Manual J. Well all they did was look at the current system in and out, and measure the inside of of the upstairs room and outside of the house. Results, he thinks we should upsize to a 3 ton upstairs. And the AC I'm getting is single stage compressor and 2 stage blower. At my wits end.. Why is it so hard to get an HVAV company to do a manual J, when that is the guidelines? Am I being to picky, it's only money. Ha. And I don't know what thermostat to ask for. Any more advice will be appreciated.
Chris
taylor8810
Original Author
9 years ago
Weedmeister, Regarding your comment about humidity on demand, I read the manual for the thermostat idicated on the proposal in first quote. There is dehumidify control setting that I can change the level.
Chris
tigerdunes
9 years ago
You need a good thermostat that controls two stage heating based on demand and is able to move both up and down as needed. And based on your location/climate, I would also want dehumidify on demand feature. Any auxiliary equipment? Need WiFi?

I would recommend HW Vision Pro IAQ Prestige thermostat. Discuss with dealer.

IMO
taylor8810
Original Author
9 years ago
tigerdunes,

it's going to be Thermostat-Lennox Wi-fi color digital thermostat. The installer does Lennox and Trane. The reason for this one is it is a communicating thermostat. I can set the humidity level where I want it, ie. 47 etc. The AC and blower will keep it at that level. Is that what dehumidify on demand is?