I have a couple quotes for a furnance and a/c system (I'm in California). I would appreciate any advice/opinion you may have. My current furnace AC system is rated at 2.5 ton for 1400 sq foot house with 14" input and output ducts.
First Quote: 3 ton 80% AFUE Trane Xl80 furnace and 14 Seer Trane XR14 A/C and replace the input and output ducts with 16". $7500.
Second Quote: (I think it's an American Standard) is to replace the furnace with a 93% AFUE (which I think I'll get a PG&E rebate of $300) AC replacement is a 2.5 ton 14 Seer AC unit. No duct replacement. $6800.
More quotes on comparable systems or varying systems from same vendor would be much more easily compared.
First thing I'd ask is whether either did an actual load calculation to size the unit or whether they simply looked at existing and eyeballed it. Unless current system is inadequate, why the larger unit is a question? Also, unless there's a distribution problem, why the ductwork modification? (Perhaps it is only a transition piece though?)
You don't give any hint as to what part of CA -- there's a world of difference between requirements in CA. Unless it's a very mild area needing heat very infrequently, I'd recommend against any unit as low in efficiency as 80% -- just doesn't make sense in the present energy-cost environment and it ain't going to get any better...
I'm thinking you need more info and choices and definitely need more info from your end to be anything more than wag's...
Sorry for the lack of info. I'm in Stockton, CA. The first vendor did a load calculation and thus came up with the new ductwork size. He place a sensor in the input and output of the furnace. There was another quote that I didn't include because the vendor wanted to sell a Peron (not sure if that is correct spelling) system. His calculation also included installation of larger ducts. His price was near $10,000 so I discluded him.
The second vendor ($6800 quote) did not do any load calculations.
I still think you need more or to evaluate what you've got more thoroughly.
I know roughly where Stockton is, but would have to do a lot more work to have any feel for the actual heating/cooling loads to comment more than I already have on the issue of a (relatively) low-efficiency furnace --- I still don't think that makes much sense these days. At a minimum I would discuss the "why" of the ductwork sizing and ask for a comparative bid on a 90+% unit from the first guy and an option w/o the new ductwork. Then you could at least compare two nearly equivalent systems, but a third would also be good imo.
The ductwork will only really affect the velocity and if you've had adequate heating/cooling previously without drafts being an issue, I don't directly follow the reasoning for the changeout w/o additional information. Your initial post didn't provide comparative data on the heating units, at least in a consistent format. Heating is rarely, if ever, given in tons, so still not clear whether the furnace output was also upgraded or not by either/both or whether the proposed units are the same or not. While the increase from 2.5T to 3T on the A/C side isn't all that much and, if I'm not mistaken, cooling will be your main load, again if you weren't short of cooling previously when the system was functioning well, it's possible you might be overcooling. That he apparently did a load calculation and included some measurements is somewhat reassuring, but still another for consistency's sake would seem prudent.
I don't recognize the third vendor's system so can't comment. Unless it were something like a ground loop or ultra-high-efficiency, would seem quite expensive.
American Standard makes Trane. The Trane price seems a little low, there's probably a reason for that. To get a furnace, ac and ducts replaced here in northern ca is ballpark 9500.00, depending on brand, effiency, etc. I'd spend an extra two grand and get the American standard plus have the duct work done.
The system is a 14 seer system. It more likely than not will not provide correct airflow without the ducts being replaced. If the ducts are sized incorrectly then this will affect the effiency of the system. Additionally, Ca requires the ducts be leak tested per title
>Your initial post didn't provide comparative data on the
The third vendors "system" is Puron. That is R410A refrigerant. My experience with those systems is that if the contractor does a load calculation based on an R22 system and comes up with 3 tons then a Puron system needs to be 3.5 tons as they do not cool as well as R22. Having said that, R22 refrigerant will be phased out starting in 2010, this means that if you ever have to have an R22 system recharged you will pay out the nose.
That's a good point and quite possibly valid. I suggested only I would want to know the underlying reason(s) in making the decision.
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Ah, yes...I was trying to connect it to a manufacturer, not the process, thanks...
But, the conclusion drawn doesn't make follow -- R410A systems may have to physically be sized somewhat larger than R22 systems of the same rating, but the actual heating/cooling ratings are measures of overall thermal output. 3T is 3T (unless the manufacturer "cheats" on the ratings and those are _supposed_ to be certified).
I still don't like the first contractor's matching a high-efficiency A/C unit w/ a low-efficiency furnace as a general idea...
So what would cool quicker, 3 tons of ice or three tons of cold water? when it comes to Puron, they will tell you that three tons is three tons but real world proves that to be bs. Go ahead and put a three ton Puron system in, you'll see. When the company I work for started using Puron systems we had nothing but complaints until we oversized them by a half a ton.
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