Purchasing Furnace - 2-Stage Variable vs. Standard

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I'm currently shopping for a new furnace. I'm replacing an 80% (or less) efficient standard furnace from 1991. I've had 3 quotes so far, and the last one really threw me for a loop. The first two quotes were from "national" companies, one affiliated with Trane, the other with Lennox. The third was from a local HVAC shop.
The first two suggested that a 90% efficient 2-stage variable speed furnace would solve some of my perceived problems with the heating/cooling in my house (short cycling, difficult to cool converted attic). After listening to their advice and the "facts" about how I can save hundreds from my gas/electric bill, and that the system would pay for itself in ~5 years, I started to feel comfortable with the idea of plunking down $4500+ for a new furnace (with all the extras).
The third estimate was from the small local shop that exists on word-of-mouth business. The sales/service tech laughed when I told him he was the first guy to not try to sell me their top-of-the-line furnace. He suggested a Carrier (actually Payne) standard 90% efficient furnace. He was the only one to stick his hand in the blower and pull out handfulls of dust, explaining that the previous owners didn't service their furnace and that likely my evap coils were caked in gunk, preventing air flow and reducing the effectiveness (and efficiency) of my furnace. He thought that poor maintainance (and a furnace that was too large) was likely the root of my problems. He also suggested that it would be unlikely that I could get back as much of my intital cost on a higher end furnace with just savings in gas and electricity. His suggestion was to use the money I would save up front and put a down-payment on some new windows if I wanted to really save heating/cooling costs.
My home is from the 1950's with original windows and poor-fitting hanging storm windows, approximately 2000 square feet. I live in the suburbs of Chicago, so I probably run my furnace 4 months/year and run the AC 2-3 months/year.
Does anyone have any thoughts on the real value of standard, 2-stage, or 2-stage variable furnaces in older homes with less-than-perfect insulation and windows? I was going to post this to alt.hvac but I figured I would get redirected here anyways. I know some of those folks read both groups.
pipco
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I think your local guy gave you honest and correct advice. As much as I'm in favor of high efficiency appliences etc, if your windows are that old and leaky, that would be the place to start. In fact, I would put that ahead of replacing your current furnace- it may just need good maintenance and could last a few more years, but suit yourself as far as that goes and listen to the advice of this guy who looked at it. If it is too large, it will tend to short cycle, more so as you plug leaks/ improve insulation.
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I'm replacing it because it has 2 cracked heat exchangers. This was discovered when a repairman was out to replace the igniter that had gone out. He ordered us not to run the furnace, but it's cold! I'm aware of the risks and have a working CO monitor in the house. Even if I could replace the heat exchangers under warranty (which I can't) I feel that this is a sign of things to come, so the furnace must be replaced.
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Are you crazy? CO monitors have been known to fail. If you don't wake up one morning, will you have enough life insurance to take care of your family? If one of your family members doesn't wake up, will you be able to live with the guilt? Turn the damn thing off and get some supplemental heat. That local contractor can probably have a new heater and (unconnected) refrigerant coil installed within days of you signing the contract.

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No, I don't think I'm crazy. Just realistic. I've done some research and I don't believe that there are any notable cases of a CO death based on a cracked heat exchanger. Usually it's something else that has gone wrong with the furnace. I will be replacing it within a few days. Like I said, I'm aware of the risks... Okay, maybe I am crazy.
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I guess you must be extremely lucky, and nothing bad has ever happened to you. It's not realistic to think that because the odds are low, it won't happen.
Carbon Monoxide:
Each year, according to CPSC, there are more than 200 carbon monoxide deaths related to the use of all types of combustion appliances in the home. Exposure to carbon monoxide reduces the blood's ability to carry oxygen. Often a person or an entire family may not recognize that carbon monoxide is poisoning them. The chemical is odorless and some of the symptoms are similar to common illnesses. This is particularly dangerous because carbon monoxide's deadly effects will not be recognized until it is too late to take action against them.
Carbon monoxide exposures especially affect unborn babies, infants, and people with anemia or a history of heart disease. Breathing low levels of the chemical can cause fatigue and increase chest pain in people with chronic heart disease. Breathing higher levels of carbon monoxide causes symptoms such as headaches, dizziness, and weakness in healthy people. Carbon monoxide also causes sleepiness, nausea, vomiting, confusion, and disorientation. At very high levels it causes loss of consciousness and death.
http://www.cpsc.gov/cpscpub/pubs/452.html
About Combustion Gases/Carbon Monoxide
Every year about 500 people die in their homes from carbon monoxide poisoning. In some cases an entire family dies from this completely preventable death. What is carbon monoxide? It is a poisonous gas that interferes with blood's ability to carry oxygen. Carbon monoxide is produced when a fuel is burned, such as natural gas, propane, fuel oil, wood, charcoal, and gasoline. In furnaces, boilers, water heaters, wood stoves, and fireplaces, carbon monoxide and other products of combustion are vented to the outside through the chimney.

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The "national" companies hire contractors to do the installs. You're paying the overhead and profit for two companies, plus a salesman's commission. Every appliance is required to have a sticker saying how much it will cost on average to run. Compare a two stage vs. a standard 90+ furnace, and you may find that the added cost is not worth the payback. Also remember that two stage furnaces have a higher frequency of repair rate. The tech from the small shop was telling you straight. They want your business, but are not willing to lie to get it. Payne is a good brand. Go with the highest efficiency air conditioner you can get, as long as it isn't Puron (R-410A). Right now, my Payne wholesaler only has 12seer units. In the spring, they'll get 13seer units. Go with the local guy and put the savings into windows and doors.

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Bob, I thought all AC units now used R-410A (Carrier calls it Puron). A Trane dealer told me that Trane was also using R-410A. He also said that both Trane and Carrier were experiencing leakage problems because of higher R-410A pressure.

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I know for a fact that Rheem/Ruud and Payne still make R-22 units. If they think R-410A leaks are a problem, wait until untrained techs start trying to add refrigerant the same way they've been adding R-22.

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There is a U. S. Federal tax credit in force for 2006 for buying at a certain level of efficiency. It is a little quirky with the standards so I could not get it because I needed a packaged unit and none met the standards. However you should check into it, it may sway you toward the higher efficiency unit.
Frank
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Interesting. According to http://www.house.gov/jct/x-60-05.pdf (page 82 of the pdf) a qualifying furnace (for the $150 tax break) has to be 95% AFUE:
"A qualified natural gas, propane, or oil furnace or hot water boiler is a natural gas, propane, or oil furnace or hot water boiler with an annual fuel utilization efficiency rate of at least 95."
Now, Trane's top of the line Varaible 2-Stage furnace is 93% AFUE... so, I'm not really sure if that is a realistic tax break right now for current furnace technology. I don't know about water heaters. Who knows, maybe there is someone out there that can benefit from this tax credit.
Thanks for the idea though!
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I think you're going to see higher seers and hspfs this summer.
wrote:

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I think the answer to the question of 80% vs 90% is based on info you should have. Take your last gas bills from a full winter and see how much you spent on gas. Or better, see how much more you are spending this year with rates higher and factor that in. Come up with an estimate of how much you will use per year going forward. Then take 11% of that number. That is about how much you will save with 90% vs 80%. You current furnace may be even less efficient, so you may save more, but it's a starting point. Now you can figure how many years it will take to recover the higher cost. In Chicago I think the coclusion you will come to is that 90% does make sense, provided you intend to live in that house for a reasonable period.
I also doubt that the cooling problem in an upstairs location is going to be solved by a new furnace. This is typically a problem with poor air flow to that area, either supply ducts, returns or both. Did any of the contractors bother to carefully examine that? That problem can be very difficult to solve if there is no easy way to add bigger/more ducts. Did they do a load calc to figure out the correct furnace size?
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Thanks. I'm planning on getting a 90% efficient furnace. My real question was about 2-stage and variable speed furnaces. Although the more I read about it, I don't think the varaible speed furnace is the silver bullet to my problems, especially with the age of my house and less-than-perfect insulation/windows. I'll probably just go with a standard 90%.
No one has done a load calc yet. They all say that before installing they will do a load-calc to ensure the correct size, although everyone has suggested 80,000 btu.
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Load calculations sound real nice, and make a good impression. In reality, the new equipment (and it's air flow) must match your existing duct work. BTW, In my state there's a 3 day "cooling off period" in which consumers can change their mind. This can be waived by the consumer in an emergency.

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Frank Boettcher wrote:

was this in effect also for taxyear 2005 ? installed in '05 a package SEER 16 unit and would love to know more.
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I don't think it was. I'm pretty sure the government was waiting until after you installed yours.

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I would take the $$$ savings and invest in upgraded insulation FIRST! then windows and finally walls. Our home iss from 1950 adding more attic insulation REALLY helped a LOT!
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I agree that insulation is important, but do a heat loss on an average older home. Then change the R-value of the attic. Then go back and change the infiltration value. I think you'll see why windows can be a better investment.

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wrote:

I don't think so. And sixteen might not have done it. In my case I was willing to pay the extra for a sixteen (which would have made it for an air conditioner) but a packaged heat pump had to have a HSPH if 9.
It does not exist.
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