Lifetime of 80% vs 90+% furnace

Okay folks, Mr. Consumer here. Remember the original question, which was basically is the lifespan of a 90+% really 2/3 that of an 80%. The reasons were longer run times and "design characteristics", and I suspect the latter include two-stage vs single-stage.

I was taken aback by comments that a two-stage is more for comfort than efficiency. Also took note of another statement that a variable-speed blower is more efficient that a single speed (and I would assume a multi-speed, too).

Let me boil my concerns into a simple question: What type of furnace would give the lowest overall operating cost/year, electrical & gas combined? At this point it looks like I would want a 90+%, single-stage, with a variable-speed blower.

BTW I may be an ignorant (but learning) consumer, but I'm not too bad at math. This argument on duct loss keeps comparing apples (input BTUs) to oranges (output BTUs). Please get past that (my ducts are in the conditioned basement, so my losses end up in the building anyway) and perhaps discuss some other efficiency/lifespan differences between one-speed single-stage 80% and variable-speed two-stage 90+% furnaces. That discussion might be helpful.

Sure hope I don't get this kind of cross-talk between the contractors that bid my system...

KJ

All the cross talk should tell you something KJ. Just as you can get two entirely different diagnoses from different doctors on the same medical problem, you'll get very different opinions on some subjects here. Most homeowners just pick the answer that fits their preconceived notions.

As far as 80% furnaces having much shorter life spans than 90% furnaces, that came straight out of left field from my perspective. I've never heard that before. As far as operating costs, of course a 90+ with variable speed is going to be cheapest to run. Throw in the added capital cost, potentially higher maintenance and repair costs and the fact that people move and the picture isn't as clear.

All BS aside, go with a 90+ unit and depending on your location get the 2-stage unit.

If you purchase the variable speed blower opt to get an extend parts and labor warranty.

The single stage units normally only come with PSC blowers. They can be upgraded, but it is better to purchase the two-stage variable speed furnace to begin with.

Make sure if you opt to go with the 2-stage furnace that you get a 2-stage stat.

If you want TRUE OPERATIONAL savings you might be better off with a heat pump system (this of course depends on your utility rates). If you want some comparisons, post your utility rates.

Sorry for the debate, but I will NOT step away from someone that is misleading our fellow friends. ;)

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Originally posted by Irascible

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Originally posted by madeinusa
Thanks for showing the public what a fine representative you are of this trade with your continual unprofessional grasp of the English language.

Here little boy. Watch closely.

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More humor that I just don't get made? Or could it be that you are indeed well practiced in the art of hubris? Your extreme arrogance causes you to lose the argument before you even start - not because your facts may or may not be correct, but because no one gives a damn about the opinion of an @ss.

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Obviously you don’t get it being your sole purpose here is to argue.

When someone continues to act immature and call me names, I assume they need to be treated like the baby they are. I am not losing the argument. People are watching you make a fool out of yourself on this topic being I have continued on with the debate in a civil manner ignoring an idiot calling me names.

You are right. No one cares about the opinion of a _ss, so why don’t you stop making one out of yourself like others have told me in emails.

You obviously have missed your medicine tonight, go to bed. You are embarrassing your own company name while you make a fool out of yourself.

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Originally posted by jultzya
I’m going to lay this out as simple as I can for your little pee brain…
Here it goes, PAY ATTENTION!

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Originally posted by madeinusa
Thanks for showing the public what a fine representative you are of this trade with your continual unprofessional grasp of the English language.

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English language has nothing to do with FACTS, and MATHEMATICAL equations!

....I was refering to your name calling. Obviously simple references like this throw you off.

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The furnace is the same size whether it is a 80% or a 90%, so let’s use a 100K furnace in a 80% model, and a 90% model.

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Same size for comparing purposes only, but not for installing one into the clients home. You should be choosing the unit by matching the load requirements to the furnace’s output.

.....Stop drinking. Sizing has not been discussed anywhere in this thread.

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80% furnace:
100K input X 72% = 72,000 BTU output X 30% duct loss = 50,400 BTU @ register
50,400 / 100,000 = 49.6% loss

90% furnace:
100K input X 88% = 88,000 BTU output X 30% duct loss = 61,600 BTU @ register
61,600 / 100,000 = 38.4% loss

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So, you have changed the data once again… now instead of 5% duct loss it’s now 30%. Can you keep anything straight? And if you have a 30% duct loss (your system sucks), and you better be looking at getting it resolved for your clients!

......30% is the average loss. Obviously again, you are clueless to real world facts. Besides, you are the one who through out the 5% figure a while back which is not accurate.

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49.6% - 38.4% = 11.2

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But as you see, the formula screwed you again! Cause the FACTS are that the increase in Efficiency is 11.2%, which is still greater than the 10% I originally used for the simple saving figuring!

....at your 10% or my 11.2%, you still never pay for the difference after adding in additional costs and labor on high dollar repair items. You lose again. You ready to give up yet? Your nose is bleeding.

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11.2 gain will not pay for the initial cost difference, plus when you have to pay labor for the DC motor or the secondary heat exchanger in the 90%.

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Once again you’re throwing **** at the plate to TRY and help your case. You are only making yourself look even worse than you have already! I sure hope you are NOT clueless enough to believe manufactures only manufacture 90% units with ECM motors. If you DO believe this, you better go talk to your distributor! MANY (if not ALL manufactures), build 90% units with regular PSC motors.

....if you are putting in 90% with psc motors at a high cost, you are cheating your customer. I guess if you can not sell a real system, this explains everything.

BTW, (just to make it clear) PSC vs. ECM has no effect on the “gas efficiency” of a unit!

.....So you are saying different CFM across the heat exchanger has no effect on efficiency?

Secondary heat exchangers are normally guaranteed for life. They are manufactured from SS and have a plastic end cap. They are not a high failure item due to the fact they have no mechanical moving parts.

....Your are obviously clueless to what LP can do to them.

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Plus, 99% of distributors only stock 95% 2 speed 2 stage which have even lower efficiency in low flame for simplicity in inventory, but I won’t go there being you are having problems with simple math as it is.

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99% figure is WRONG, as many manufactures don’t even produce 95% furnaces!

....it was a ballpark statement gomer.

Now, you add even more BULL**** to your plate, which has nothing to do with the original 80% vs. 90% Efficiency discussion. Plain and simple, if your distributor is not stocking the equipment you need, have them order it or get yourself a new distributor that can satisfy your HVAC needs.

.....you seem to get lost easy, and can not follow thought patterns

On second hand, forget it. You can’t understand the differences anyway! :(

....see what I mean, you can't follow.

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I have also showed you (by your numbers) that the 2-stage equipment will still save tremendous amount of money or the 80% standard unit!

.....you are lost, and people who know this are laughing at you. You should stop now.

You also should be comparing apples to apples and oranges to oranges… as in 80% single vs. 90% single and 80% two-stage vs. 90% two-stage!

.....again, you get lost easy. Go read the 100K comparison, it was for single stage.

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Now, what was that 2hot was saying about you would bury me.

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You buried yourself. When are you going to stop feeding yourself your own shoes for supper?

.....You need to spend some money on classes so you don't make a fool out of yourself.

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Looks to me like you need to learn how to perform simple calculations before you get out here calling me names and making a fool out of yourself.

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Look above, I believe EVERYONE can understand YOU LOST THIS ONE!

....One day you will realize how lost you truly are. It is really sad to watch you.

Be a man and just admit it!

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....Go take some classes, you need them.

It's ironic that you should suggest that my sole purpose here is to argue made. I have seen you take on a multitude of people in a multitude of threads. And rather than rely on the strength of your facts to make your case you inevitably resort to calling them hacks, idiots and any number of other names.

As futile as it may be, it's entirely appropriate to call you out on that fact. If in the process I make a fool of myself in your eyes and to those who think like you then so be it. I don't seek respect from those for which I have none myself.

Hey jultzya, would appreciate that heat pump cost review!

I'm in SE Michigan, 30 miles north of Detroit, 6569 heating degree days, 626 cooling degree days.

My gas cost is $.96/CCF. Electric costs $.087/KWH for the 1st 17KWH/day, and $.101/KWH over that.

Note that there are 2 special electric plans for "space heating": "Whole house" is same except during Nov-May where it is $.087/KWH for the 1st 20KWH/day and only $.070 over that; "Supplemental" uses a separate meter for the heating unit and is $.0687/KWH.

KJ

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Originally posted by madeinusa

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Originally posted by jultzya
I’m going to lay this out as simple as I can for your little pee brain…
Here it goes, PAY ATTENTION!

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Originally posted by madeinusa
Thanks for showing the public what a fine representative you are of this trade with your continual unprofessional grasp of the English language.

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English language has nothing to do with FACTS, and MATHEMATICAL equations!

....I was refering to your name calling. Obviously simple references like this throw you off.

I see simple math problems throw you off!

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The furnace is the same size whether it is a 80% or a 90%, so let’s use a 100K furnace in a 80% model, and a 90% model.

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Same size for comparing purposes only, but not for installing one into the clients home. You should be choosing the unit by matching the load requirements to the furnace’s output.

.....Stop drinking. Sizing has not been discussed anywhere in this thread.

Oh my, I add a comment to the discussion and you get pissy. Why do you try to mix it up by adding crap to your post to TRY to make this go your way? It’s not working!

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80% furnace:
100K input X 72% = 72,000 BTU output X 30% duct loss = 50,400 BTU @ register
50,400 / 100,000 = 49.6% loss

90% furnace:
100K input X 88% = 88,000 BTU output X 30% duct loss = 61,600 BTU @ register
61,600 / 100,000 = 38.4% loss

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So, you have changed the data once again… now instead of 5% duct loss it’s now 30%. Can you keep anything straight? And if you have a 30% duct loss (your system sucks), and you better be looking at getting it resolved for your clients!

......30% is the average loss. Obviously again, you are clueless to real world facts. Besides, you are the one who through out the 5% figure a while back which is not accurate.

I picked a number, then I used your numbers… which you can see DIDN’T help you! If the duct is in the conditioned space it is not wasted. And WILL NEVER change the real data that much. There is still going to be a huge savings with the better equipment! The efficiency difference is still there in the equipment!

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49.6% - 38.4% = 11.2

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But as you see, the formula screwed you again! Cause the FACTS are that the increase in Efficiency is 11.2%, which is still greater than the 10% I originally used for the simple saving figuring!

....at your 10% or my 11.2%, you still never pay for the difference after adding in additional costs and labor on high dollar repair items. You lose again. You ready to give up yet? Your nose is bleeding.

”high dollar repair items” If you would learn to install the equipment correctly you wouldn’t be seeing these “high dollar repairs” But while we are on this subject, the 80 vs. 90 single stage equipment have the same components. With the addition of a secondary heat exchanger, drain assembly and a plastic vs. metal inducer!

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11.2 gain will not pay for the initial cost difference, plus when you have to pay labor for the DC motor or the secondary heat exchanger in the 90%.

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Once again you’re throwing **** at the plate to TRY and help your case. You are only making yourself look even worse than you have already! I sure hope you are NOT clueless enough to believe manufactures only manufacture 90% units with ECM motors. If you DO believe this, you better go talk to your distributor! MANY (if not ALL manufactures), build 90% units with regular PSC motors.

....if you are putting in 90% with psc motors at a high cost, you are cheating your customer. I guess if you can not sell a real system, this explains everything.

Who said anything about high installation costs? Who said I couldn’t sell? You drunk again?

BTW, (just to make it clear) PSC vs. ECM has no effect on the “gas efficiency” of a unit!

.....So you are saying different CFM across the heat exchanger has no effect on efficiency?

1700 CFM is 1700 CFM, it makes no difference whether it is a PSC or ECM motor moving the air! Did you forget that we were talking about 80 vs. 90? Not PSC vs. ECM?

Secondary heat exchangers are normally guaranteed for life. They are manufactured from SS and have a plastic end cap. They are not a high failure item due to the fact they have no mechanical moving parts.

....Your are obviously clueless to what LP can do to them.

You are obviously clueless as to the proper installation and proper setup procedures for such an install!

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Plus, 99% of distributors only stock 95% 2 speed 2 stage which have even lower efficiency in low flame for simplicity in inventory, but I won’t go there being you are having problems with simple math as it is.

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99% figure is WRONG, as many manufactures don’t even produce 95% furnaces!

....it was a ballpark statement gomer.

Which is just another one of your inaccuracies!

Now, you add even more BULL**** to your plate, which has nothing to do with the original 80% vs. 90% Efficiency discussion. Plain and simple, if your distributor is not stocking the equipment you need, have them order it or get yourself a new distributor that can satisfy your HVAC needs.

.....you seem to get lost easy, and can not follow thought patterns

You’re the one that can’t gasp FACTS or Mathematical equations and try to blow smoke to cover them up. It’s not working BTW.

On second hand, forget it. You can’t understand the differences anyway! :(

....see what I mean, you can't follow.

I see this went right over your head!

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I have also showed you (by your numbers) that the 2-stage equipment will still save tremendous amount of money or the 80% standard unit!

.....you are lost, and people who know this are laughing at you. You should stop now.

I see no one laughing, if they are… I’m sure it’s not at me. You can’t seem to understand the other people’s post on this topic either, Eh?

You also should be comparing apples to apples and oranges to oranges… as in 80% single vs. 90% single and 80% two-stage vs. 90% two-stage!

.....again, you get lost easy. Go read the 100K comparison, it was for single stage.

And you added the comment about the “last sentence” did you forget this already?

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Now, what was that 2hot was saying about you would bury me.

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You buried yourself. When are you going to stop feeding yourself your own shoes for supper?

.....You need to spend some money on classes so you don't make a fool out of yourself.

You talking to yourself again?

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Looks to me like you need to learn how to perform simple calculations before you get out here calling me names and making a fool out of yourself.

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Look above, I believe EVERYONE can understand YOU LOST THIS ONE!

....One day you will realize how lost you truly are. It is really sad to watch you.

Why, cause you know your getting slammed?

Be a man and just admit it!
[/B]

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....Go take some classes, you need them.

Not as much as you do! Let me know when you finally wake up from this knock out!

[/B]

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Originally posted by kjones
I'm in SE Michigan, 30 miles north of Detroit, 6569 heating degree days, 626 cooling degree days.

My gas cost is $.96/CCF. Electric costs $.087/KWH for the 1st 17KWH/day, and $.101/KWH over that.

Note that there are 2 special electric plans for "space heating": "Whole house" is same except during Nov-May where it is $.087/KWH for the 1st 20KWH/day and only $.070 over that; "Supplemental" uses a separate meter for the heating unit and is $.0687/KWH.

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Ok, by using your posted natural gas and electrical rates, below is a brief cost comparison / explanation. It will depend on the actual equipment chosen (as in all equipment will vary in actual efficiency).

Your utility rates.

Nat:
$ 0.96 per cu ft = $ 9.60 /MMBtu.
(now you have to factor in the furnace efficiency)

80% cost $ 12.00 /MMBtu
90% cost $ 10.67 /MMBtu

92% cost $ 10.43 /MMBtu
94% cost $ 10.21 /MMBtu
96% cost $ 10.00 /MMBtu

Electricity:
rate of .087 kw = $ 25.48 /MMBtu (figuring off the highest amount)
rate of .070 kw = $ 20.50 /MMBtu (figuring off the whole house heating plan)

Straight electric heat strips (.087 kw) $ 25.48 /MMBtu
Straight electric heat strips (.070 kw) $ 20.50 /MMBtu
(now factor in the HP efficiency)

Note:
As the temperature outside drops the heat pump losses its ability to transfer heat as efficiently. So the cost of operation increases, as it takes longer for the equipment to accomplish the same heating output. As you can see below;

Heat Pump:

(.087 kw)
COP of 1.9 at 0 degrees F = $ 13.41 /MMBtu
COP of 2.7 at 20 degrees F = $ 9.44 /MMBtu
COP of 3.5 at 40 degrees F = $ 7.28 /MMBtu
COP of 4.2 at 60 degrees F = $ 6.07 /MMBtu

(.070 kw)
COP of 1.9 at 0 degrees F = $ 10.79 /MMBtu
COP of 2.7 at 20 degrees F = $ 7.59 /MMBtu
COP of 3.5 at 40 degrees F = $ 5.86 /MMBtu
COP of 4.2 at 60 degrees F = $ 4.88 /MMBtu

Directly showing there is more heat to transfer at higher ambient temps, making the heat pump more efficient.

At some point the heat pump will no longer satisfy your home heating needs (could be 20-40F). At this time you will either need to assist this heat pump with electric heating strips or switch over to gas heat till the outdoor temps rise above the balance point (will depend on many factors).

If you use the electric strips you can still benefit from the heat pumps continued operation.
If you chose to use gas-fired backup, the heat pump will shut off and you will rely on the furnace to accommodate your heating requirements while the outdoor temperature is below the balance point.

As you can see (from the numbers above) the heat pump will save you considerable money while operating above the balance point.

I'll let you absorb this before going any further... ;)

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Originally posted by Irascible
It's ironic that you should suggest that my sole purpose here is to argue made. I have seen you take on a multitude of people in a multitude of threads. And rather than rely on the strength of your facts to make your case you inevitably resort to calling them hacks, idiots and any number of other names.

As futile as it may be, it's entirely appropriate to call you out on that fact. If in the process I make a fool of myself in your eyes and to those who think like you then so be it. I don't seek respect from those for which I have none myself.

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You are sicker than I thought if you think I crave for any respect from someone with the character you just displayed here in the last few posts.

I have earned the respect from people here with more credentials than you will ever accrue in this industry based on the actions you just provided.

It is funny you mention taking on others, and facts. All I have ever done here is debate facts in a civil manner until ignorant fools turn the debate into a school yard brawl, you know, just like you accomplished here. You should feel proud of this achievement. If you have a problem with a so called professional being called a hack when they represent bad workmanship here in public, or a troll disrupting this site such as yourself being called an idiot, I could careless just as others here could careless to be associated with them.

You and your yapping sidekick dog have done nothing but contribute to embarrassing this trade in an open public forum. It is that simple.

If I were Dominic or Rob, I would pull your certification for embarrassing the name as you have done here being you post it for the public to see in your credentials.

There is only one person I completely ignore here. Congratulations, you just filled the number two spot.

Too funny made. Just as in the other thread where you implied I was debating your facts when I was not, you now attribute comments about respect to me that I never made. It's in the quote right above your comments for Pete's sake! I stated that I wasn't worried about having your respect. It was already assumed that the feeling was mutual. It's ironic that one who was popping off about understanding English misread some pretty simple words himself.

As far as credentials go it's a lot of hot air. Credentials don't validate one's assertions. And the ironic part is that neither in this thread nor the nitro thread have I disputed your technical assertions. Your comments in the nitro thread agree with mine. And other than the fact that I have stated the desire for more proof of Jim Davis's assertions, I have not directly contradicted your technical comments here. If you want to condemn me as an embarrassment to the trade then you only condemn yourself. Our differences are rhetorical, not technical.

In any event you have offered up a very happy solution. I am thrilled that you choose to ignore me. It will please KJ to no end. And it will prevent future pointless debates. Kudos to you.

Madenusa called everyone hacks in the ( flowin nitrogen ) if they didnt use it . Now he claims he's beter than you if you call him names ! He wont put up his name in the Credentials ! What a piece of work . BH

hey kj
not here to argue, just throw out some trivial info.
i live in an area where the utility company has given rebates on high effi. equipment for over 20 yrs. so i work on alot of 92 percent furnaces. i see alot that are going on 20 yrs and have had minimal probs. the key is installation and maintanence which i know has been mentioned before. most of the 92s that i work on have a lifetime heatexchanger warranty so really until parts are not available there is no reason to replace the furnace. some of the manufactures will quit making the heat exchangers after 20 or so yrs and then they will pro-rate the furnace. some will give you a brand new furnace (amana did this last winter) some will just give you a couple hundred dollars towards a new furnace, from them of coarse.
i have been seeing some manufactures advertise that they will give you a new furnace if the heat ex. ever cracks, i am sure that there is some stipulations with this but it sure sounds good.
also the government is offering a 150 dollar tax credit if you buy a new furnace over 95 percent efi. in 05 and 06 and they will give an extra 50 bucks if it has a variable speed blower. this may help some although it will not offset the cost completely. i wish i knew how to tell you to file for it but i have not had the time to check into it myself. i know several threads have talked about it so maybe someone else can throw out that info for you.
finally if you are not sure you will live in your house long enough to pay for the upgrade from 80 to 90 you can just add the couple hundred dollars onto the cost of the house. i cannot believe that a buyer would not be cheching the heating equipment and utility bills. you are further north than me and it is a very hot topic here especially with gas prices going up. smaller more efi homes always sell faster than bigger less efi homes.
oh yeah and the heat pump is an excellent idea since you have special utility rates. the gov. also has a tax credit on these too, but they have to be a minimum seer.

hope this helps!
hope i dont go up in flames for the advice!