Furnace and AC replacement

14 years ago

Seems like this is a common topic here so please bear with me as I'm a newbie.

The basics, location Carmel,IN, just north of Indianapolis. Summers can get hot, especially humid, winters normally not too bad but generally at least a few days of sub zero. House is 2200 sf, 2 story, full crawl. Current system is Rheem, 23 years old. Furnace is 75,000 btu in, 80% efficient. The AC (2.5 ton) needs some major repairs, $600+. The furnace appears fine, but old. As a result I have been getting quotes on replacing both, and have narrowed it down to 2.

First option: Carrier Infinity 96 furnace and Infinity 16 heat pump, 3 ton. Includes Infinity thermostat, and a Honeywell media air cleaner. Dealer is also bumping up the warranties to 15 years parts and labor. Price after all rebates, tax credits, etc., is $6482. Sounds like a good deal. These are my issues with it:

1. No Manual J done. He is quoting a 120,000 btu in furnace, much larger than any one else. That seems inefficient to me. Maybe he has several in the warehouse?

2. I am leery of heat pumps, but from reading the forum that may be old school. Apparently the "cold" air blowing from them for heating issue has been dealt with and the reliability is not worse than a standard AC unit. True?

3. It seems like getting a dual fuel system will result in a high efficiency furnace doing noting but running a fan for at least half the winter. But with the tax credit, one is almost forced to go that way.

4. I know Carrier has a single stage heat pump (not Infinity) with a scroll compressor that is almost as efficient as the Infinity 16, but so far I can't get a quote on that setup from the dealer. Should I?

5. Many forum posts talk about the air handler. There is nothing like that on this quote. Should there be?

Second option is from a guy who did a Manual J calculation. It is an America Standard Freedom 95 furnace, 60,000 btu, with an American Standard Allegiance 14 2.5 ton AC unit. Digital thermostat, I assume the American Standard version of the Honeywell stat, but I don't know. Price after rebates and credits is $5845.

1. I appreciate the Manual J, but this seems small, compared to my existing unit. Will the increased efficiency, variable speed blower, etc. make up for that?

2. The AC unit is single stage, I assume not a scroll compressor. Can't tell that anywhere for sure.

3. Again nothing on the quote about coils/air handler, etc.

4. American Standard appears to have parts only warranties, lifetime on the heat exchanger (apeears to be on both exchangers), and 10 years on everything else. There might be a 1 year labor warranty.

No one has even looked at the duct work or said anything about it. Is it logical that it can handle either of the proposals? I'm leaning toward the Carrier, but I need to know why the furnace size and if a smaller one will get the price even lower. The warranty is what is really pushing me. Any input would be greatly appreciated, as it's 90 degrees today and I need to have a decision by Mon.

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Comments (5)

ryanhughes
14 years ago
last modified: 9 years ago
#1 is just oversizing the furnace and not looking out for your best interests. Newer furnaces need to move more airflow, and if the ducts can't handle the added air (and likely can't), could get loud.

I'd pick the properly sized and installed American Standard before the Carrier Infinity system installed by an incompetent dealer any day. 15 year parts and labor warranty isn't through Carrier, so I hope the dealer is around in 15 years.

60,000 btu furnace x .95 efficient = 57k btu's
75,000 btu furnace x .80 efficient (when it was new) = 60k btu's

If they did a Manual J, they should be able to guarantee its performance and comfort at certain temperatures.
westfield
Original Author
14 years ago
last modified: 9 years ago
You are right, the last 5 years are through the dealer. However, they have been around here for awhile and have a good reputation (except for this sizing issue.) I am meeting w/ them in their showroom tomorrow and will attempt to get an answer.

As to the Manual J calculation. The guy who says he did one measured the exterior of the house, noted the orientation, asked about the insulation and that was it. Maybe that's all you need, but I thought it was a little more involved. If it is, then I guess I have a mini-Manual J. I did tell that guy that the existing unit has trouble cooling the second floor on hot days. He said that was more likely an issue of ductwork sizing instead of AC sizing, but left it at that. He did guarantee the sizing would be correct.

What about all this coil/airhandler stuff? Is that an issue or if it is a matched system, no problem.

I just talked to the Lenox guy who quoted a G71P 90K unit. He said the high effeciency units don't blow as hot as the unit I currently have so he sized 90K as a comfort issue. Does that make sense? (Not interested in his quote b/c of price and poor Lenox warranty.)
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When looking at the Infinity and other "2 stage" systems, the comfort is what should be the selling point, not necessarily the return on your investment. It will be more efficient, yes, but the higher-efficiency units don't necessarily pay for themselves given the upfront cost. As far as bringing the bids down as low as possible within reason, I'd be careful with this only because you don't know what corners, if any, will be cut. Some companies have room to go a little lower; some will end up taking shortcuts to cut their ultimate cost. Sometimes sharing your price from another company will cause them to match that price and maybe more. It all depends on the trust you have in the sales rep. A good, reasonable and reputable company should already have a reasonable price. If you're looking for a good system without the bells and whistles and within a reasonable cost range, I'd look at 14-15 SEER A/C units with with furnaces with variable speed blowers to help with humidity, efficiency, and overall comfort. You can also get a thermostat with the ability to control the blower speed to dehumidify.
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We also have a dual fuel HP in ATL (13 SEER + 80% NG furnace). If you're going to invest that kind of $$ in a new system, plus pay to operate it for the foreseeable future, I'd do everything I can to ensure I got a quality install. Below is a link to a Southface Energy Institute fact sheet on blower door and duct blaster tests. They're an ATL non-profit. I highly recommend the info they have on their site. They might even be able to help or point you in the direction of a contractor to design your system and/or test your house/ducts. Ideally, you'd have the blower door done to feed into the Manual J sizing of the system. Then, after your new ducts were installed and sealed (but before insulating), you'd have the latter done to test how tight the duct system is. A brand new system, installed right, ought to leak at about 0.05cfm/sq ft of living space. That's only 125 cfm for your house. If at all possible, you want to maximize the amount of rigid ductwork, only allowing flex duct at the runouts (I'd get at least the Vision Pro w/ an outdoor sensor to control the switch to Aux heat. My understanding is that the IAQ version will handle the staging possibilities better than the 8000 series VP. It also costs more. I'd also be interested in getting a HP w/ good low temperature performance. Our gas bills have gotten smaller since getting the VP set up to control the switch. But on an old house, you're still going to use gas for the days in the teens/twenties like we've seen this winter. Anyway, food for thought. We have used ACS to do work on our system. They sell Carrier equipment. Here is a link that might be useful: Southface on blower doors and duct blaster testing
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1. You're right 2. You're right again. I noticed that right after I posted. I was going to update it, but now I don't have to. 3. Yes, it is the Carrier Infinity Controls..I don't know which model number but I'd guess it's SYSTXCCSAM01. 4. The old system was a 130K BTU system. The guy who came did a load test by measuring the rooms, checking the ducts, and windows, etc. He said the old one was over-sized. Rather oddly, the AC was only a 2.5 ton system so that was undersized. As for how the old system worked for us, we had big problems in the winter with uneven heating and out of control gas bills. Same issues with the AC, but that's a little easier to deal with I guess.
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A very general rule of thumb is the installed price is twice the equipment cost. On top of that you have to add additional labor charges if the installation is difficult, during peak season times, etc. It is hard to imagine why this guy is quoting $50K. You need to get more quotes. You want an HVAC contractor who will do a load calculation. If the contractor can't do the calculation then keep looking. Installing a mini-split for a large addition is not a bad idea. How big is the current hot water heater? Most families can use a 40 or 50 gallon hot water heater tank and never run out of hot water. The tall type may be a better fit. I also recommend installing low flow shower heads. Those are now the code for any new faucet. You will be amazed how much hot water you save.
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ryanhughes
14 years ago
last modified: 9 years ago
"I am meeting w/ them in their showroom tomorrow and will attempt to get an answer."

Don't let them try to say because it will run on low stage most of the time. The furnaces need to be sized for their high stage capacity. The idea is it will run longer in low stage, not short cycle, using more gas and causing less comfort.

"I did tell that guy that the existing unit has trouble cooling the second floor on hot days. He said that was more likely an issue of ductwork sizing instead of AC sizing, but left it at that. He did guarantee the sizing would be correct."

He is correct. Most cooling issues are due to ductwork when one level doesn't cool as well. There are things that can be done, including balancing the system with dampers. Did he measure the windows? Did he use a laptop or a chart to calculate the size (Manual J)? If he guarantees it will keep it at the temperature you want it to be on the hottest or coldest days, then this is the most efficient way to go, and the most comfortable way--with properly sized equipment.

"What about all this coil/airhandler stuff? Is that an issue or if it is a matched system, no problem."

An air handler is used with a heat pump or just an air conditioner and includes the coil and a fan (often called a "fan coil"). Your furnace is acting as the air handler, and has a coil sit over the furnace.

The Lennox equipment should have a 10-year parts warranty and limited lifetime warranty on the heat exchanger. 15 years is not standard, if that's what you're comparing other manufacturer warranties to. See if that 15 year warranty requires an annual maintenance contract, and read the fine print. Sounds too good to be true. The G71MPP comes in a 70k size, which is probably more correct and would have even more output capacity than your current furnace. The 90k would probably work fine as long as ductwork is sized appropriately because it is a modulating furnace and would more than likely never use the 90k fire rate.
westfield
Original Author
14 years ago
last modified: 9 years ago
He did none of those things. He noted the answers I gave him on paper. I left while he was measuring the outside so I suppose he could have estimated the second floor window sizes. The only room of the house he was actually in was the kitchen. I have doubts I really got a Model J, but he at least tried harder than the other guys. I would have thought he would have followed up his ductwork response with some suggestions, but no.

The Lenox does have a 10 year parts warranty. The quote said 5 year parts and labor, so I assume the dealer is throwing in the 5 year labor part. (The sales guy has penmanship issues.)

I will check the fine print. I have a copy of it at home.

I should have mentioned that the furnace is in the garage and of course there are upper bedrooms at the farthest distance from the furnace. Any dampers would have to be installed in the crawlspace, but that could be done. Again though, not suggested. I'll ask him.
westfield
Original Author
14 years ago
last modified: 9 years ago
15 year warranty requires a maintenance agreement for the duration. I believe the current price is around $160. Of course the claim is that is cheaper than paying for the separate annual heating and cooling check. Of course the first 10 years of parts are on Carrier since they don't appear to have a labor warranty either.

Furnace and AC replacement

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