Brands here are equal so that shouldn't sway the decision. Ask #1 to quote two systems and #2 to quote with new metal ducts and your decision should be easier. I have hunch the cost of maintenance agreement in #2 will more than make up any difference in cost.

You need to find out if the zone system being quoted includes a bypass and what type it is.

If it doesn't include a bypass, not a good thing. Usually they increase the size of the ducts to pull this off. During hot summer days this can cause lack of capacity problems. 'lack of air velocity' when both zones call.

If it includes a bypass and the bypass is 'barometric bypass'. It's a duct damper with a weighted arm on it, position sensitive and guaranteed not to work very good.

bypass included and it's a 'modulating bypass'. This is the better of the two, but sizing and design of the zone system is critical.

Additionally the dampers that control air flow to the zones -- are they 'spring open' or 'spring close'. If they are take a pass. The better of the dampers are 'power open and power close' (no springs)

The Trane equipment sounds undersized compared to what you originally have in the home. 2 ton + 2 ton = 4 ton not 3.

Additionally a down side to the Trane option is that this system is not a communicating system.

A two stage communicating system will do a much better job because the thermostat communicates with the indoor and outdoor equipment.

Amana and Goodman both have these options available with a better warranty to boot.

The communicating zone system is doable, you can set up the zone system with both communicating stats or just one on the proper zone to control the system via communication protocol. This type of set up is NEW, the communicating zone system just became available this year. So you may have trouble finding exactly what you want in this arena. But this would be the better choice. (better comfort / better warranty protection)

Thanks for the input guys. I'll probably try to find any remaining reputable HVAC companies in the area and get another two system quote WITH a load calculation. Does my Quote #2 seem like a fair deal for the equipment provided? At the very least the engineer (owner of the company) seemed to care about providing a quality service. I immediately tossed two or three quotes because they just came in, took a peek and tossed out a number.

Austin Air Companie,

There was another portion on the quote that I left off. Here is the full text:

"Integrated Trane (2) zone control system to isolate independently by thermostatic controls: Includes Zone panel, motorized control dampers, freeze protection device, low voltage transformer, 2 WIFI enabled thermostats, Trane's top of the line Comfortlnk series XL950. OPTION: EWC 2 zoned system with bypass damper and sensor. I DO NOT recommend this option. It requires the use of a bypass damper to bypass airflow back to the return plenum when 1 or more zones are not calling. It's an economical way of zoning. Also, bypassing the cold air can confuse the TXV (thermal expansion valve) resulting in loss of humidity control."

That second "option" reduces the quoted price by ~$1000.

Thanks guys!

Cody,

Try getting some quotes from bigbox guys. In NJ, they use reputable contractors. Off so many (more than half dozen) HVAC contractors I had for quotation, only one guy did a proper manual J calculation. The folks who ballparked it, were close. Point to be taken- while manual J calculation is something desired, most will not do it.

Aside that, why you are picking up a 80% AFUE furnace? Cost difference is minimal and on a longer run, I am not seeing energy price to go downhill.

I don't like combining the two system into one; the installation and upkeep seems too complex. With two independent systems, you can fall back on one while the other one needs attention.

The zoning and dampering sounds complex to keep it operating correctly for the merged system. The problem is that a system needs a minimum air flow to operate and if it is cut in half it might have issues. Probably better to keep it separate. I believe in good air quality but some of the electronic media filters emit some ozone. Check if they are installing an electronic or a non-electric.

https://www.arb.ca.gov/research/indoor/cr-12-2007.pdf

Plenty of non-electric media filters out there.

https://www.alpinehomeair.com/viewcategory.cfm?categoryID=403

Otherwise concerning air flow, the large 6" filters are not very restrictive. So you shouldn't be afraid to get those types of filters.

I agree with Vth. My thinking is try to keep it simple even if you have to spend a little more money. Most HVAC contractors are not good at zoning. The one who proposed zoning may be good, but it is still a compromise over what you have now.

@ Cody,

Motorized control dampers doesn't specify which type, for that reason I would almost suspect a 'spring' open or close type damper. (these are still motorized but one sided 'either power open or power close' but not both. In other words if the damper is 'power open' it would be spring close and vice versa. A power open AND power close damper is a better more efficient motor.

Bypass takes a lot of heat from contractors that don't know, or care to know what they are doing. A zone system is 'a lot of work' behind the scenes in prep work and then going into structure and actually doing it. If there is a team doing this the challenge is even greater because many times the design may fall on those doing the work. Lack of communication or know how and you're not going to have anything you want. (nothing but problems)

The problem is that if you omit the bypass, the system is no where near as effective under all scenarios and could reduce efficiency and may even cause problems more so than it attempts to eliminate.

I have a zone system in my current home and I am in the process of installing a zone system at my new home that I am moving to soon. (I am the one actually doing the work so I have very intimate knowledge of zoning systems.)

I also did a zone project a year ago for a 3 level home in which there was no 'bypass' installed. How they got around this issue was to 'over size' the duct work. (There has to be some where the air can go when only 1 zone is calling.)

What happened was that during hot times the upper level (3rd floor) would not get cool enough. The cure was to rip out the existing zone system and add zones for better control and install a 'powered' bypass. (replacing the duct work is not an option in a 3 level home easier to just tear it down and start over.)

So with this home the problem still exists, but only when all zones are calling at the same time and it's hot outside. Which really isn't a problem because when people sleep the main part of the house that damper closes down and supplies the bedrooms, when people wake up the bedrooms damper down and the supply goes to the main house.

If you have a properly sized duct system along with correct bypass, the difference is 'night to day'. I know because I feel the comfort and the efficiency of this type of system in my own home.

The problem is finding someone who 'knows' as opposed to someone who just offers something from a competitive standpoint trying to sell it to you that way.

'Bypassing air confuses the TXV resulting in a loss of humidity control': This means I have no idea what I am doing. (It's complete nonsense.)