Choosing Furnace Efficiency

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Our gas utility is giving rebates for buying a greater than 92% efficient furnace. There's also a tax credit available. These greatly reduce the premium for buying such a unit and then of course there is the savings in gas.
On the other hand, are these machines more prone to problems and need of repairs than a simpler furnace? That could wipe everything out. Plus it might be beyond my abilities to repair. The old furnace (see other thread) I could do most maintenance. I was even able to solve a problem that stumped a pro many years ago. (Not his fault...it just didn't act up when he came.)
I know the pros of the super efficient furnaces. What are the cons? The ones being considered are Carrier Performance Series. What are HVAC techs putting in their own homes?
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On Monday, December 2, 2013 10:27:39 PM UTC-8, Big Giant Head wrote:






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Before worrying about a more efficient furnace have you done everything els e to make your home more efficient? Do you have double windows, and a thick , even insulation in your attic and crawl space under the house? Did you ch eck all your ducting to make sure there aren’t any leaks and that it is w ell insulated? Are all your outside walls insulated? If you do all of these you probably won’t even need a more efficient furnace, and you won’t n eed an expert to insulate.
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Excellent points but I'm pretty sure the existing furnace has a cracked heat exchanger and replacement is mandatory immediately. (See seperate thread about that.)
But since you asked, no the house is terribly inefficient. Built in 1957 with metal window frames, no insulation in the walls, concrete slab floor. It does seem laughable to have a super efficient furnace in combination with those things and if one were choosing what to put money into, it would be these other things first.
On the other hand, all of those things mean more heat is required and a super efficent furnace is going to make more heat with less money. If rebate and tax credit pay for most of the difference then maybe this is the way to go.
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On 12/3/2013 1:59 AM, Big Giant Head wrote:

The techs I talk to, say that the early versions of high efficiency had problems, but now days they are much more dependable. Mine is a York, down flow in my trailer. It's about 90% efficiency, didn't say on the box. The only trouble I've had was that the draft inducer fan went bad, it some how wore through the outer shell, and I had to replace it. Took me a couple hours to track down another fan, and put it in.
With today's political climate, very often the choice of anything is based on what is subsidized, rebated, or politically correct. As you've got a cracked exchanger, I'd go in the direction of whatever is subsidized.
If you're figuring to do insullation and such, please consider going down a size of furnace. Me, took out 80K unit, and put in a 70K. And also some cellulose in the ceiling. That is keeping me comfortable.
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"Big Giant Head" wrote in message

Excellent points but I'm pretty sure the existing furnace has a cracked heat exchanger and replacement is mandatory immediately. (See seperate thread about that.)
To check for cracks in the heat exchanger , close off all heat registers. Run furnace and when blower starts watch the burner flame. If there is a crack the air pressure will blow against the flame and you can see that movement. That is how the gas utility checks it. WW
But since you asked, no the house is terribly inefficient. Built in 1957 with metal window frames, no insulation in the walls, concrete slab floor. It does seem laughable to have a super efficient furnace in combination with those things and if one were choosing what to put money into, it would be these other things first.
On the other hand, all of those things mean more heat is required and a super efficent furnace is going to make more heat with less money. If rebate and tax credit pay for most of the difference then maybe this is the way to go.
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Big Giant Head wrote:

Hi, I have performance series 96%, 100K BTU one going into 3rd year of service. Installed by pro installer who knows what he is doing. So far not a single problem. My ac unit is also matching performance series 3 ton unit little older than furnace, No problem either. So far all I did was cleaning the condenser unit at the beginning of season. This week we're experiencing -35C with lots of snow and cold wind.
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On 12/03/2013 01:27 AM, Big Giant Head wrote:

High efficiency furnaces are trouble-free for the first 7 years or so but then furnace hell begins.
I paid $420 to have the draft inducer replaced on a 9 year old furnace.
One of the vacuum safety switches also failed but that repair was only $140.
So any fuel savings is easily offset by higher initial cost and huge repair bills.
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Because of the rebates and tax credits, it sounds like a wash or better for initial cost. Let's say he does have the $560 in repairs in nine years. Have you saved less than that in fuel cost?
Apples and oranges, but my oil savings with a more efficient boiler are in the $800 a year range so in 9 years after repairs I'd be $6600 ahead. Rather than take your blanket statement, the OP should run the numbers and factor in some repair cost.
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On 12/03/2013 05:54 AM, Ed Pawlowski wrote:

Very impressive, Ed!
So you are comparing a cheaper 80% efficiency furnace with a more expensive 96% efficiency furnace?
Using your $800/yr savings and a 16% more efficient furnace, your original heat bill must have been approximately $5000/yr.
While I can see where it pays for you, my entire heat bill is less than $500/yr.
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On 12/3/2013 2:22 PM, Just Joe wrote:

No, comparing a high efficiency with my old unrated burner. That makes the percentage higher. As I said apples/oranges

Right, that is why the OP has to run the numbers for his situation. Few houses in the north can be heated for $500 a year.
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On Tuesday, December 3, 2013 3:27:31 PM UTC-5, Ed Pawlowski wrote:

Also the cost difference for the furnace itself is just a few hundred bucks. The installation will likely add to that, because you're typically going from a chimney situation, which is drop-in to a direct vent. How hard or easy that is depends on the house specifics.
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On 12/03/2013 03:27 PM, Ed Pawlowski wrote:

The OP's furnace has a cracked heat exchanger and must be replaced so the only question is should the OP buy an 80% or 96% furnace.
The difference is 16% fuel savings...period.
Your numbers and your old unrated burner isn't relevant here. Gawdamn, are you related to trader4? Sheeeesh!
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On 12/3/2013 7:10 PM, Just Joe wrote:

I told you it was apples/oranges. Ill type it slower for you: "the OP has to run the numbers for his situation" You statement that repairs are more than savings has no proof and no merit.
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Depending on the furnace, he's right. Takes a long time to save $400 worth of gas by buying 16% higher efficiency. Replace ONE $400 board and those savings take a long time to pay it back.
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In the last 20 years I have never spent $700 for natural gas here in Ontario Canada. That is heat and hot water.
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snipped-for-privacy@snyder.on.ca wrote:

Hi, If house is small enough, LOL!
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wrote:

about 1300 sq ft 2 storey
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On Tue, 03 Dec 2013 21:39:13 -0500, snipped-for-privacy@snyder.on.ca wrote:

That is a rather small footprint. Being a two-story, it's naturally more efficient.
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On 12/3/2013 7:17 PM, snipped-for-privacy@snyder.on.ca wrote:

I know people that will spend that much in January. You save $116 in a year, they save $116 in a single month. But we still cannot draw any conclusions for the op
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Figuring in the hot water usage, the savings would work out to about $90 a year if I had put in a 96% over an 80%. What I put in is a "high efficiency non condensing" 2 stage furnace - supposed to be 86-90% efficient. Most of the time it is running on low output, which is supposed to make the 90%.
When I had it installed, putting in the high efficiency condensing furnace would have cost me over $800 more - for an extra 6%. - to save about $30- $35 a year.. Even if I saved #40 a year, it would take 20 years to pay for it, and I DOUBT this furnace will last more than 20 years. The original was about 30 years old. So 10 years ago I didn't put in a condensing furnace. My brother did - and it's been replaced already. If I was replacing it today, it would be a high efficiency condensing furnace because that's all I can buy now here in Ontario.
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