AC help please from the AC experts

[AUswimKC]

Thanks for the additional info.
I will have to look into the duct testing. Attic should be under 120. It has really good ventilation when the fan is working. When I got it fixed last year I want to say the temp was 110.

Are there any brands I should put on a short list? Any to avoid?

[blackhat]

Lennox, Trane, Carrier or any of the ICP family.  Goodman and Daikin residential are to be avoided.

[AUswimKC]

Ok, more questions. I figured I would ask here in the forum in the event it might help someone in the future.

Single stage v. Two stage.

Is there any savings when comparing a 16SEER single v. a 16SEER two stage AC/furnace? Or is it all based on potentially more comfort by running a bit more at a lower speed thus reducing humidity?

I’m trying to compare and contrast and decide. Three options so far it seems. 14SEER single(6500$), 16single(8000$), 16two stage(9000$). There isn’t much difference between the 16s but a big jump from 14 to 16 for only $50-60/yr per online calculators when comparing the single stages.

[AUswimKC]

Latest comfort specialist added another variable. A 16seer single stage compressor with a variable speed furnace blower.

I think my head is going to explode.

[daddo]

If I were to look at this job and based on the information you provided that the upstairs isn't dropping the temperature as it should, I would start there. I'd check to see if it were the system(s) not performing as it should or if it is the structure. I'd check the ducting size, type, and if it is sealed well. I'd probably use the infrared camera to see if there are hot spots in walls or ceilings where the insulation is inadequate or missing- the direction of windows (Direct sunlight) and if they are sealed well and attic ventilation and infiltration.

Then I would do a load calculation (Upstairs and down) and use the numbers as they are- no manipulations other than unknowns.  

It gets even more complicated I hate to tell you. How is the manufacturer going from 14 seer to 16 seer (single stage)? Are they using a compressor with a slightly smaller total capacity- different blower- larger or smaller indoor coil......?  

A two speed (stage) system is ideal for comfort. It will have the best humidity control to achieve this- (actual run time). Other than that, the monetary savings aren't what you might expect after 10-15 years compared to a 14-15 seer system.

If I'm not too worried about humidity, I still like the more durable/dependable 14-15 seer with the variable speed indoor motor set for ramping to help control humidity. But ask 5 what they like the most and get 5 different answers. No two homes are exactly the same either.

[AUswimKC]

Ok. While my head is about to explode with all of the possible options etc, I have several quotes from severa different manufacturers.

To level the playing field, let’s assume each is quoting a simple single stage AC and furnace 14SEER or 16SEER.

Cost not factored in, which of these brands would you purchase first? I know that some problems take a couple years to manifest in bunches but any real world recent experience helps.

I have quotes from Carrier, Lennox, Trane, and Ruud

[blackhat]

I would say Trane or Carrier interchangeable, Lennox and Ruud distant last.