All of these quotes are excellent equipment. The only question seems to be whether 2 ton or 1 1/2 ton for upstairs. I prefer Trane because it has electronic demand defrost feature which Bryant/Carrier does not offer.

What size heat strips do you have now? 5 KW may be too light. I would consider a 7.5 KW which would better temper the air on a defrost call.

5020850 Active Systems XL15I WEATHERTRON TRANE 4TWX5024B1 *AM7A0B30H21 835 24000 13.00 16.00 22600 9.00 13400 1 HRCU-A-CB Yes 186 552 Yes

The XL15i system has an extra 2 yrs on compressor warranty over the XR15 plus the proprietary funky top which I like and have myself.

Prices may be a tad high but certainly not unreasonable.

I would want HW Mdl 8321 thermostat. Same as Trane's 803. It has humidity sensor for dehumidification in cooling mode.

How do you filter your return air? Several returns for each system?

IMO

Noisy air flow usually indicates the duct work is too small to handle the air flow. I would think the 1.5 ton for 650 sq. feet on the second floor would be fine. It would also mean less noise.

If 1 1/2 ton then system below. a 5 KW heat strip would be fine for this size system.

4655312 Active Systems XL15I WEATHERTRON TRANE 4TWX5018B1 *AM7A0A24H21 605 18800 12.50 15.00 17100 8.40 10000 1 HRCU-A-CB Yes 155 355

Pay attention to thermostat recommendation.

IMO

The prices aren't bad for our location. Get a thorough Manual J heating/cooling calculation done as I think both units are oversized. You may well be happy with two 1.5 ton condenser units with variable speed air handlers which would reduce the airflow/noise (unfortunately, 1.5 ton is the smallest split system made otherwise a 1 ton would probably suffice for upstairs). Two ton will cool the house down just fine but it won't dehumidify as effectively.

Coincidentally, I recently replaced two systems the same as your existing ones (only in 3 ton sizes). Leaking, frosting over, noisy, etc. I'm not sure that generation Carrier system was one of their better efforts! You will be changing over from R22 to R410 so make sure they flush out all the old refrigerant and oil and check for leaks in the old line sets. You might want to just go ahead and change them if they are accessible.

EDIT: I'm presuming you don't have access to natural gas, which is much cheaper to heat with in our area than electric?

This post was edited by sktn77a on Wed, Jun 11, 14 at 14:37

Thanks for all the comments, this is very helpful!

Here's some additional info:
* Existing heat strips are 5kW, these seem to have been sufficient in my experience
* Natural gas heat is not available in my neighborhood
* Existing air returns are a single 20" square inlet for each system with a 1 inch filter

Here are some additional comments from the Trane vendors:

Vendor #1: Air handlers are both TAM7AOA24 (2 ton); the other Trane vendor proposed the 2.5 ton both floors, thermostats are "Honeywell 7000 touchscreen programmable", adding Trane Perfect Fit media cabinets to each air handler would increase cost to $11,451

Vendor #3: When asked about his load calculation said that the upstairs came in at just over 1.5 ton. Thermostats are Trane tcont803a. Would add Trane Perfect Fit media cabinets at no charge, total of $11,376

At this time I am leaning toward Vendor #3 for providing slightly higher grade equipment at similar cost but would appreciate some insight into the different system sizes proposed, the 1.5 ton heat pump + 2 ton air handlers (#1) versus the 2.0 ton heat pump with 2.5 ton air handlers (#3); Also I don't know if the thermostats are comparable.

Thanks!
Ty

I wouldn't oversize the condensers. You can go up in size 1/2 ton with the air handlers and this usually improves dehumidification and efficiency. Just make sure the blower motors will step down the airflow to match the tonnage of the condensers, or you'll still have the noise problems you have now (maybe even worse).

Ask contractor #3 to show you why he thinks you need 2 tons of cooling upstairs (that's 1 ton per 325 sq ft - twice the usual rule of thumb). Unless you have a lot of south facing glass, no insulation in the attic, bad ductwork, and/or lousy envelope sealing, 2 tons sounds way overboard for 650sq ft.

Make absolutely certain the Honeywell thermostats control all of the features of the Trane air handler. If not, get the matching Trane thermostats.

"Vendor #3: When asked about his load calculation said that the upstairs came in at just over 1.5 ton."

I find this hard to believe. Ask for a copy of the calculation. Don't surprised he won't show it to you.

Obviously a question on the sizing of HP for second floor. I agree with Mike about wanting to see the load calculation. But I will also add that I don't want to be borderline sized for AC cooling in Durham, NC. Not certain if there is opportunity to reduce load with insulation improvements. If you want to perform the load calc yourself, I can provide a link but there is a nominal charge to use.

IMO

Hi all,

I thought I'd post a follow-up to this so future readers know how things turned out.

I didn't want to start doing the load calculations myself because I think it is pretty clear that a simple calculation would call for 1.5 tons upstairs and the 2 ton result is driven by adjustments for the particulars of the house, mostly cathedral ceilings with high windows, skylights & no attic in part of the upstairs and substantial air exchange between the first and second floor. I did talk with the 2 vendors who recommended the 2 ton upstairs units about their load calculations, explaining I wasn't interested reducing the cost, just in getting the best fit system, etc. One asked for copy of the floorplans but both got back to me later that week to say that even on further review the 2 ton was correct.

I went with the system proposed by vendor 3; 2 ton Trane XL15i with TAM7 air handlers. Install went smoothly and the systems worked great, there was a hiccup a month later where one of the air handlers failed, due to an issue with a valve not properly seated at the factory according to the technician who got it back up later that day.

Best features of the new system:
Outdoor units are much quieter than the old ones
Programmable thermostats

Surprises:
New outdoor units are much larger than the old ones

I can't comment on the efficiency or change to our electric bills yet since we haven't had a full month with the new units installed where we weren't also gone on vacation in part.

Finally, during the install the technicians changed some of the damper settings in the upstairs ductwork to reduce flow rates in some inconvenient locations; this helped.

Thanks for all the help!
Ty

if 5 KW heat strip on a 2 ton XL15i system, then too small to temper the air on a defrost call. And definitely too small for emergency heat. This is simply a rookie mistake.

IMO