Has anyone ever replaced their conventional furnace fan motor with an ECM motor?

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Full-Quoter snipped-for-privacy@optonline.net wrote:

You've admitted that furnace life-spans are getting shorter today vs years ago.
Isin't that proof? Isin't that an example of how they are coming down to match (but never fall below) the average length of home ownership?

If in 5 years we observe that the lifespan of the average new furnace is 7 years, does it matter if we call that a "goal" ?

Any old furnace that's 25+ years old can have it's efficiency raised easily by 10 to 20% simply by turning down the burners. The design goal for those old furnaces was to blast out the heat in those un-insulated homes. They had no concept of constant heat. They had crappy mechanical thermostats and couldn't achieve constant (comfortable) heat output.
Now those homes have added insulation, and if you turn down the burners so the furnace runs longer (but cooler) you've just raised their efficiency and probably increased their lifespan too. Adjust the burner primary air baffles too so that you're not blasting the flames straight through to the flue (ie - increase flame residency time within the heat exchanger to extract more heat from the flames -> slow the flames down).
And I think it's a crock that your only choice is to replace a 45-year-old furnace with one with an expected lifespan of 20 years. I don't give a damn about how much fuel savings there will be. There is no logical reason why lifespan needs to go down when efficiency goes up.

Back in 1955, what was the inflation-adusted price of a furnace?
Were people paying a fortune back then for furnaces?
Are furnaces today less expensive (in real dollars) compared to 10, 20, 30, 40 years ago?
What good is it if you pay less for a furnace today vs 30 years ago, but you have to buy it twice as often?
You're telling me it's a good thing for the environment to have to buy a furnace every 20 years vs every 40 years? Do you know how many more households there are now, compared to 40 years ago?
We have 95% efficient furnaces today. You're saying it's a bad thing if they last 45 years - because we want people to replace them more often. So I suppose we want them to last only 20 years - because 20 years from now we'll have a 98% efficiency? So for the sake of a few extra percent we want people to buy new furnaces? What the hell kind of logic is that?

Who are you?
A home owner?
Or an HVAC reseller/installer?
If the energy-saving argument is correct, reliable, proven or garanteed, then I don't have to wait for my 45 or 30 or 20 year old furnace to break down. I can choose to replace my furnace at my conveinence. Or not.
Saying that it's a good thing that furnaces last only 20 or 25 years is a crock. If that's what you rely on to make the case to buy a new furnace, then that's a bullshit argument.

Do you know how many old fixtures, tiles, railings, etc, are being torn out of old homes to be installed in new or renovated homes?
Don't confuse style with function. Those old fixtures went out of style 30 years ago, but they still function, and now they're back in style.

Many people do.

I've got a news bulletin for you.
You don't need a furnace full of electronics, sensors and computers to get 95% efficiency. We have 95% efficiency because we have more heat exchangers, essentially more "plumbing" inside furnaces. Closed combustion, intake air pre-heating, etc. Not even electronic ignition is needed (that is another gimic that saves very little energy, and certainly saves no energy when the burners are running).
Of course they knew what it took 50 years ago to build a 95% efficient furnace. There just was no demand for it.

We're not talking about AC. That's another matter.
And if you want to know how "plumbing" can help even more - I'll tell you.
Ductwork should be gated such that in the winter, air can flow around the A-frame instead of being forced through it. And in the summer, air should be ducted so it doesn't have to flow through the furnace heat exchanger.
Take those resistances out of the picture and you've just raised the efficiency of the system. No fancy electronics required.
And you've got no comment about this eh?
| In Japan, they have furnaces with built-in 1 kw electric | generators to provide some electrical co-generation that | can supplement the electricity supply for the house - and | keep the blower running in the case of complete power | outages (like what's happening to thousands in the central | USA right now).
http://www.greencarcongress.com/2005/04/honda_pushes_in.html
http://www.energyefficienthomearticles.com/Article/alternative-energy----Micro-cogen-for-homes-/2039
The biggest crock of shit about furnaces today is that they can't generate their own electricity to run their friggin internal mainframe computer - and their blower motor during a power outage. I bet the electronics in today's furnaces consumes more electricity than the ECM fan motor does.
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In a word, no. That's like saying because the average power tool one buys today lasts for a shorter time, the goal of all the power tool manufacturer's is to reduce the lifetime of their power tool products to two weeks worth of use.
In other words, yes, I agree a furnace doesn't last as long today. But that is a reaction to market forces, ie what customers want and what they are willing to pay, just as it has always been. There is no master plan to reduce furnace life to 7 years.

Yes, it does. Because you claimed it was an intentional plan by all HVAC companies to do exactly that and I see no proof of it.

I'd like to see you take any old 45+ year old furnace and make it 95% efficient.

I would wager that just like most other things, the answer to your question is yes. I'll bet if you look at what a furnace 40 years ago cost and adjusted for inflation, you're getting a new far more efficient, lighter, easier to install furnace today for a whole lot less.

Well for starters, if it cost about 1/2 as much you'd be way ahead. And that's because you wouldn't have to shell out the extra money decades ago for a product that cost more so that it would last 40 years. Plus, it's obvious today's furnaces are far more efficient so you're going to save on fuel. Plus, they have new convenience features, like a variable speed motor. Didn't this thread start because the OP wanted to save energy by trying to retrofit an ECM motor into an old furnace? If he paid a reasonable price for the furnace and it's near the end of it's life, then he can buy a whole new more efficient furnace that includes that feature. He could even consider switching fuels, maybe going to a heat pump, etc, depending on his location.
That's what customers want. Say a new HVAC system costs $6K and lasts 20 years. That works out to a whopping $300 a year. Consumers are spending way more than that for energy. Way more than that for all kinds of entertainment items. So, spending that per year for a HVAC system, seems very reasonable to me. And of course if you limit it to only a furnace, it's even less.
That's what manufacturers are reacting to and building for.

Yes, I think it is and as I pointed out, environmentalists, govts, and utilities agree. Which is why they offer rebates to encourage people to replace old inefficient furnaces with new ones.
Again, you focus on the energy used to make the furnace, but completely ignore the bigger amount of energy used to run an old inefficient one.
I'd like to see one credible referrence to anyone that agrees it's better for the envrionment to continue to use a 40 year old furnace or HVAC system instead of a new one.

No, I'm saying if a manufacturer built such an HVAC system today, it would cost so much that few customers would want to buy it. Manufacturer's for the most part, aren't stupid. If they saw a market segment opportunity for such a product, they would offer it.
So I suppose we want them to last only 20 years - because 20

I'm saying if you look at the cost/benefit and value proposition, around 20-25 years is the sweet spot. It means customers don't have to shell out extra money upfront and that in 20 years, the furnace is depreciated and they can look at whatever energy alternatives are available then. Are you clairvoyant enough to know that in 20 years the same fuel will be the best choice? By then, the energy situation could be entirely different and then maybe a different system would be better instead of being locked into a more expensive system that lasts 40 years.

A homeowner. A homeowner with a 23 year old HVAC system that is nearing the end of it's life. It doesn't owe me a thing. And I'll be happy replacing it with a new, more efficient system that lasts about as long.

That ignores the fact that it's going to cost significantly more for a 40 year old system upfront. Factor in paying more upfront and the time factor of money over 20 years, ie interest that could be earned, and the 40 year furnace is what's a crock.

Do you know how many HVAC systems are being torn out of old homes and being installed in new ones? Zero.
Do they take some special old fixtures out of some old homes for resale? Sure. What percent of times does this happen? So small it's not worth talking about as applied to the broad market.

I've been through dozens of new construction homes in the last year. I've yet to see one with a 40 year old toilet, rail, or anything else. Sure it happens in some cases, but it's a niche market. In fact, if you want to talk style, most people looking for that old look style typically buy a new version of that product, ie they go down to the plumbing supply and buy a new claw foot tub.

That doesn;t answer the simple question of whether 95% efficient furnaces were available 50 years ago. And you missed the elephant in the room. For whatever reason, that 50 year old furnace is no where near the efficiency of one you can buy today. So, what;s your point?

No, it isn;t. Because today most people have both as part of one system. Are you telling us that it's also economically sound to run a 30 year old AC system that was bolted onto a 50 year old furnace instead of simply getting a new system? Or that one should just replace a failed 30 year old AC system on an even older furnace? LOL
But again it shows why 20-25 years is the sweet spot in terms of system life.

Yes, I do. If you're so smart and know the technology and market environment so well, why don't you go get venture capital, start a company and build HVAC products designed to last 50 years. I'll bet the system will look a lot like the car Homer Simpson designed for his brother's car company and have similar success.
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On Dec 23, 9:10 am, snipped-for-privacy@optonline.net wrote:

Ive been told new furnaces heat exchangers are thinner to transfer more heat and be more efficent, an old unit I took out weighed alot more but was real inneficent. Stainless Steel exchangers with a long warranty maybe 20 years are offered by a few.
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Full-quoter ransley wrote:

It makes sence that a thinner heat exchanger is more efficient.
It also means that the older furnaces get more efficient over time as the walls of their heat exchanger rust away.
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Full-quoter snipped-for-privacy@optonline.net wrote:

Unless I add a second heat exchanger, no, it's not going to reach 95%. But there's no reason it can't reach 78% efficiency. Without adding computer controls and electronic sensors.

If "most other things" are cheaper today (in real dollars) then that must mean we're all richer today vs years ago.
I suspect that most other "important" things are not cheaper today.

Well, I welcome some hard numbers here otherwise this is just speculation.

It is not environmentally sound for me to buy a new 95% efficient furnace that lasts maybe 15 or 20 years (instead of 30 or 35 years) and replace it with ANOTHER 95% efficient furnace.

What if that 40-year-old furnace is a 90+ furnace?
What if it's an 80% furnace?

It's a no-brainer that natural gas will always be more economical vs the only real alternative (which is electric heating).
And if we run out of natural gas in 30 or 40 or 50 years, then welcome to the world of Mad Max and the end of civilization.

Like I already said, they could have made condensing furnaces 50 years ago. I bet some were available for special situations.

I already made my point.
It doesn't take computers and electronic sensors to make a 90+ condensing furnace. It takes more heat exchangers and more "plumbing" (ducting, etc) inside the furnace. More sealing, a closed combustion loop, and more work at the job site to install and plumb (duct) it all into place.
Back when natural gas was cheap, of course the industry and customers are going to ask why build a more complicated (expensive) furnace when the fuel is so cheap? Instead they built long-lasting, durable furnaces.

It doesn't matter if the evap coil is built into a furnace or if it's installed in the plenum above it. The AC unit is a completely separate system that just happens to share the same ducting and blower as the furnace. And as I've stated, it's actually inefficient to combine the two without gating because it does add resistance to air flow.

The economics of the furnace or the AC unit has got nothing to do with one being "bolted" to the other.
If the furnace is 50 years old and if the AC unit is 30 years old then you look at those units separately when analyzing their cost of operation. The fact that they're "bolted" to each other doesn't matter - the "bolting together" doesn't affect their relative efficiencies or costs of operation.

LOL yourself.
I don't have the same hang-up that you do where you see the furnace and the AC unit as inseparable.

As has been pointed out several times in this thread, current 90+ furnaces are struggling to achieve 15 years of service life.
I can totally understand that the average american is so strung-out (money-wise) that hvac makers are responding by making units that barely hang together and that builders are putting crap like that into new construction.
But what I can't understand (if this is the case) that all hvac makers have changed ALL of their model lines such that they no longer offer units that absolutely will last 30 - 40 years (and then charge accordingly for them).

Changing your ductwork as I described above is not related to changing the longevity of the HVAC system.

The AC evap coil (A-frame) is an unneeded resistance for the furnace. Would you like to argue otherwise?

I don't know if you've noticed, but most HVAC installations don't look pretty when all their various lines, connections, and ducting is finished.
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Some Guy wrote:

Hi, This type motor is known for failure mode for motor and controller going out together. Most people who has this thing in their furnace, they take out 10 year warranty for that part. If you buy and use it as constant speed blower at an expense, that is fine for the purpose of experiment but economy wise I don't think you'll recover initial cost and if it fails......
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Tony Hwang wrote:

That is all probably true.

In a previous post, I've already roughly calculated that I'd probably save $40, possibly $60 per year if I changed my PSC motor for an ECM motor.
The question that I continue to ask is: What is the "over-the-counter" price of an ECM motor?
I can walk into any hardware or farm supply store and buy a 120v, 1/3 hp PSC motor (for $75 to $150).
Where do go when I want to pick up an ECM motor?
Who sells them "over the counter" ?
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Some Guy wrote:

Hi, Lennox is known for selling parts only to trade people. You can contact other brand supply house or try on-line search. Another issue maybe mechanically fitting it into your existing set up. Prepare to pay over a grand for motor and controller. How much is electricity cost where you are? I have locked in rate of 7 cents per KWH for next 5 years.
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Tony Hwang wrote:

That sounds like a crock of shit. I guess the HVAC industry is full of companies that limit the availability of parts to the general public. Stone-age thinking these days.

I agree, but that's my problem (if I go down that road).

Again the controller issue. Has anyone ever seen a data sheet for these motors?
Has anyone considered that the controller is built into these motors, and maybe they have just a few control lines for speed selection - that can easily be rigged up for manual control (or set to run at a constant speed) ???
While on that topic - are there any electronic thermostats that can control multi-speed motors?

I pay 10.6 cents per KWH. That includes ALL direct and indirect costs. Indirect costs include taxes, delivery charges, regulatory charges, etc. The electricity itself is billed at about 5.8 cents per KWH.
When my meter is read, the reading is multiplied by 1.0421 (some sort of correction factor for line losses I guess).
Does your cost of 7 cents include ALL miscellaneous charges and taxes?
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http://www.nailor.com/pdf/ECM_1.pdf
http://www.enviro-tec.com/pdf/catalog/HP-FanPerformanceECM.pdf
http://www.eere.energy.gov/buildings/appliance_standards/residential/pdfs/furnaces_boilers/furnace_boiler_app8_7.pdf
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"Dr. Hardcrab" wrote:


The above two are more like sales sheets or flyers, not really data sheets with pinouts and wiring diagrams.
But still, they confirm that the controllers are built into the motors, and they can either be set to run at constant speed, or constant air flow (not sure how exactly they can sense airflow), or they can take a control voltage (2-10V) which is trivial to set up next to a thermostat.
If I had one of those, I'd tinker with it to see if I could get it to run off a DC supply. A DC battery backup would keep a motor like this running during winter power failures. I bet there are some in the plains and mid-west who know all about winter power failures.
"Most variable speed electronic devices, including the ECM operate with a rectified and filtered AC power. As a result of the power conditioning, the input current draw is not sinusoidal; rather, the current is drawn in pulses at the peaks of the AC voltage. This pulsating current includes high frequency components called harmonics."
So these motors are likely to radiate RF/EM noise if filtering isin't used (and given manufacturing price pressure I wouldn't count on these having proper filtering).
And one more thing - the power utilities really like these non-linear loads - NOT!
"ECM (tm)"
Someone trademarked "ECM" ? Are you kidding?

http://www.eere.energy.gov/buildings/appliance_standards/residential/pdfs/furnaces_boilers/furnace_boiler_app8_7.pdf
Yea, I've seen that one before.
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