First, looks like he's oversizing the furnace so you can get the tax credit, when with a 3 ton typically 80-100k is the furnace matchup. For 1500 + 550 sqft., 120-140k heat sounds like much more heat than needed for your mild climate. Ask him what your calculated HEAT LOSS figure is. Especially for an upstairs system and an attic, sounds like the furnace is oversized which is not a good thing. That furnace will likely need to move much more air than your current ductwork can handle, even when one zone is calling.

To your questions:

1. 140k btu vs. 120k btu. Also, TDD is downflow, and TUD is upflow (* denotes an A or T for American Standard/Trane).

2. See above. The 5 ton refers to the blower, which is okay if (and only if) he adjusts it to match your 3 ton system. The airflow is adjustable. My concern is the oversized heating capacity. Heat does rise from the first floor.

3. Given your mild climate and that its an upstairs system, I would not consider dual fuel as I don't see the payback.

4. Given the fact that it includes zoning, and it's Trane ($$$), price sounds reasonable. That's a hard question to answer without seeing the job or knowing what's involved. The media filter is a good idea, and so is the new lineset (if properly sized and flushed properly, doesn't always need to be replaced).

5. They are not the same thermostat. One difference is the IAQ can stage the backup heat (2 furnace stages), and can also slow the blower down to dehumidify. However if zoning, the dehumidification feature may not apply since the thermostat goes through the zoning panel.

6. If you don't replace them, make sure they're sealed up.

7. Zoning could account for likely $1-2k of the installed price, depending on what's involved with installing the dampers and configuring the zones.

8. I like to see Trane coils used. I prefer them over ADP coils.

Ryan, thank you so much for the feedback. This is such an great informative forum and I'm glad I found this site.

Yes, they have to over-size the furnace to just be qualified for the tax rebate. Blame on Trane for their current lineup I guess. Not best situation to be an honest Trane dealer if you have to either over size something or use a third party products to take advantage for the tax rebase.

The load calc says "Total Heating Load = 61506" so 120-140k BTUH sounds way too much. Plus, I'm concerned now you pointed out the furnace will likely need to move much more air than your current ductwork can handle.

What's my alternatives if I want to stay with Trane 3 ton Heap pump either XL15i or XR15?

Regarding the IAQ may not be used to trigger to slow down the blower when combining with zoning. Where do I check to be sure? Also, does the triggering even possible with XR15 like it does with XL15i?

I think the reason I try to go with a Hybrid system (duel-fuel) is that over here in central NC it does get pretty chilly during Jan and Feb with temprature down to single digits at night for a few weeks. It seems to me it will be prudent to have some sort of back-up heating during this periold. And if adfing a heap-strip with Heat pump/Air handler, I think I have to add a circuit break or something. At least that what I had been told. To other folks on the forum, do you have your advice on choosing a dual-fuel hybrid system vs just heap pump + heap strip? Specifically, anyone in the same area that has done this before?

Today the Bryant dealer came and spent only 15 min looking at my attic. He took away my drawing of the 2nd/3rd floor plan with window and room sizing and said he would run it over the weekend through a load calc program to see what's the corect size and propose some setups for me. I guess I won't know any details for a few days.

Again, thanks for the feedback. If I don't get to talk to you again here, have a very nice weekend Ryan!

carrydan,

I live in Southeast, also have a dual fuel system, and have to admit that I question that load calc for heating.

I do agree with Ryan on all the points he listed to your questions.

I would not have these oversized furnaces as backup heat.

could you explain why you want to zone the upstairs and added attic space?

I personally would look at a straight high eff HP with VS air handler and backup heat strips. ask dealer what is necessary to upgrade your electrical service.

keep in mind the 2nd floor will receive some residual heat from the first floor heating system.

if you are intent on dual fuel,I would shop around for another brand that has a proper size furnace. or perhaps look at a 95% eff furnace with straight AC-at least you can be sized correctly as well as get the tax credit.

IMO

I agree with tiger's recommendation of a straight heat pump with air handler and heat strips. It would be sized for the cooling load but handle both heating and cooling (with backup heat strips to supplement when and if necessary). Much better option than oversizing a furnace. Trane's XL15i 3 ton with v/s I know does qualify. If you do wish to stay with dual fuel--and that will be your decision--I would avoid oversizing, and it may be possible with other brands other than Trane.

I live in Maryland, and I've been happy with just a straight heat pump (though certainly I would prefer the warm air of a furnace for the whole house, I think for upstairs, a heat pump would be a great route to consider). It does most of the heating, until it gets very, very cold, and then the heat strips come in to assist.

I would ask what zone panel (model) they plan on using. Baldloonie, another member here, seems to know quite a bit about zoning panels and how they handle those types of functions.

Good luck with the decision and hope the Bryant dealer gets back to you with good, feasible options. Have a great weekend yourself.

By the way...I have a friend who recently moved outside of Cary in Morrisville. Quite a developing town/area--I enjoyed spending a few days down there.

Hi Tiger,

Thank you for chime in.

The third floor attic, when finished, will be of limit use but eventually my teenage kid might want to claim the space so it will be a living quarter someday.

So I don't want its temprature settings totally controlled by the stat down at the hallway of second floor. Hence the 'zoning'...

My Trane guy also said if I go with zoning, I can't use XL16i since it's two staged and I would have problem with zoning. I didn't get the rational completely but I know all you guys recommmend staying away from XL16i, I didn't ask further.

I will ask him about the XL15i 3 ton with v/s handler plus heat strip next week.

The Bryant guy today mentioned the possibility of leaving 2nd floor AC alone and add a ductless mini-split system on my attic. What do you guys think of that idea? I like the idea of having one system to handle both 2nd and 3rd floor.

Ryan, I actually live in Morrisivlle, a couple hundred yards away from Cary line. I always say Cary since not many people know Morrisville, then again not everyone know Cary either...in which case sometimes I would say I am from Raleigh NC...

Did you have a good time when you were down here? Pretty nice place, isn't?

I was down there in April. The weather was great, and the houses I saw were beautiful (big, some on golf courses, which is a plus). If I lived in NC, I wouldn't mind living there one bit--didn't seem too different from the suburban type area I'm used to. Wish I got to see more. Have you spent any time in Maryland?

Let us know what you hear back from these dealers in the next few days. Good luck with the new system. I'm not actually in the HVAC profession, just a homeowner like yourself that has gathered enough information to be worth some help.

Btw, the load calc is all over the place. A whole ago I had someone else came up that 61506 figure. That guys said I had to have a 3.5 ton. The Trane guy's calc is much lower, to a point only needs 2.5 ton on paper. He did backed out a little bit saying he isn't too comfortable to remommend me to go only with a 2.5 ton and eventually we agree a 3 ton unit probably is the best choice.

I know it's hardly scientific and but in the end of the day, most guys came didn't even measure let alone to run a load calc. They just told me I need X tons.

The zone system he proposed is a Honeywell zoning system. I don't know any details but probably should.