New gas furnace/AC recommendations?

[The Daring Dufas]

Hey, I could hand crank my 1967 Renault 10 with the screw jack handle. :-)

TDD

[Home Guy]

Unless you can show where someone has made some blower CFM measurements in a real house, then you have no real evidense to support that paradoxical statement.

And in any case, an ECM motor has no way to know how much CFM is being moved by the fan its running, especially as a drop-in replacement for a PSC motor.

And I bet that modern furnaces that come with ECM motors also don't know how much CFM they're actually pushing. They probably only know indirectly by monitoring return-air and output-air temperature difference. Do any of them have an integrated wind-speed sensor?

Then put a number on it.

The home-owner is "often" too stupid ... in some instances. ?

That's a mixed message. You want to say that some arbitrarily large fraction of home-owners would (or are) choosing a fan-speed that too high (you'd have to show me how they have any real control over that, btw) then you back away by saying "in some instances".

You are showing a strange bias against homeowners that is affecting your ability to think rationally about this.

Yes, let's compare these other situations, where micro-power DC motors have been used:

So you think that these tiny, micro-power DC motors make for a good analogy when we're talking about the furnace fan motor market eh?

Tell me how many consumer furnaces were available in 1985 with ECM motors.

And you haven't told me anything to support your claim that ECM motors last longer.

Saying that the first ECM motor was made a hundred years ago, or that GE supposedly actually sold a furnace with an ECM motor in 1969 (which maybe they withdrew from the market a few years later ?) is not an answer to why ECM motors last longer (your claim).

Don't change the subject. We're talking about longevity, not efficiency.

Yes, they run hotter. They are also constantly cooled by the airflow generated by the fan.

Tell me which motor is more likely to survive constant use in a high-resistance duct system? Or survive a fan bearing that gets gummed-up over time? Or a filter that's not properly cared for? Or a power spike or brown-out on the AC grid?

That depends on how many PSC motors are multi-speed vs single speed.

And you can get high-efficienty PSC motors in the range of 62%, as claimed here:

And I suggest you also read this:

Any furnace that has a shaded-pole variable-speed fan motor does have horrible efficiency, and perhaps some people here are confusing shaded-pole motors with PSC motors in these discussions about motor efficiency.

It's clear that when we're talking about 1/4 and 1/3 hp single-speed PSC motors, efficiencies up to 60 - 65% are obviously the norm, and bring us much closer to ECM motor efficiency than most people think possible.

It's clear that some furnace makers are using puny or wimpy ECM motors in their furnaces. But none of the HVAC regulars reading this will chime in and agree.

ECM motors have sophisticated electronics that PSC motors don't have. When-ever you include additional components into any system or device, you have more points of failure. You stubbornly refuse to believe that the electronics in an ECM motor represents an addition point-of-failure that PSC motors simply don't have.

[Steve]

Ok homer, so when are you going to start you new job with the manufacturers and/or governing bodies to redesign and reclassify furnaces so that you can turn a multi billion dollar industry back in time 20 years??

[clare]

At least ONE. I'm done. You are too stupid to be teachable.

[trader4]

Excuse me, but I think the points Home Guy are raising are perfectly valid and you can't just dismiss them. You claimed that slowing down a fan motor may not lead to less airflow. I agree, thatis possible, IF the fan is turning so fast that it's no longer moving air, ie cavitation has occured. But that isn't the abnormal case we're discussing now, is it? We're talking about a normally operating home forced air funace or AC.

Also, HG raised a perfectly valid question of how a drop in replacement ECM motor could learn anything about air flow. It can't directly measure the CFM being moved. He asked a question I'd like to know the answer to, which is in new furnaces with ECM, do they have air flow sensors?

Also, to add to HG's case, I think all the hoopla about constantly circulating air 24/7 is a bunch of BS. Why? Let;s look at my house, which I'd say is typical. Furnace is in the basement, returns are uninsulated and some to upstairs even flow through outside walls. Those ducts have no insulation, because the wall cavity is used for the ducts and the insulation that the normal cavities would have is absent. Also, typical ducting is far from perfect, with leaks in botht the returns and supply commong.

So, now I'm to believe that running a blower 24/7 when it's 20F outside, drawing the air through the cold basement, the cold furnace that is not fired up, through ducts that are in outside wall, etc, is a smart thing? I don't care how much you think you save in an ECM motor. Even if the energy to run the blower is free, the rest of the above equation spells loss to me.

[clare]

It is an all too common occurence when guys who do not understand what is happening try to "fix" their furnace.

Which someone has screwed around with

In most cases, if not all, no.

Not all basements are cold. A very large percentage of urban basements are heated, finished living space.

To you it might be. To me, and many others, it is not.

And I've checked the air temp from the heat outlets on the outside walls of my house - they are room temperature or better with the burner not firing

I've stood up for HG on many issues - but he'll never get it. The days of the model "T" are long gone - and the day of the standing pilot light, atnospheric burner, PSC fan gas furnace are pretty well gone too. Taking all the "advancements" off of today's equipment will not make it a) last longer b) work better c) cost less long term or d) run better.

He first argues for resizing the jet - which I agreed with him about, and adjusting the air dampers, which I also agreed with him on, then he starts talking about putting the gas valve "between settings" - referring to the 3 position gas valve as "variable", and adjusting the flame by adjusting the gas shutoff valve on the 1" iron pipe feeding the furnace. Sure he can reduce the flame that way - but it is sure not the right, or even an adviseable way to do it.

[Vic Smith]

We've beaten to death "modifying" furnaces to improve efficiency. It can be done with older furnaces because they just weren't designed with efficiency as a high priority. The priority was quick heat on demand. I wouldn't try modifying a modern "efficient" furnace. Correct sizing is what you want, so more heat goes through the heat exchanger and less up the stack.

Beyond that - and insulation - I've found the best way to reduce gas use is to not heat where it isn't needed. Working vents are important, as are just closing/opening doors. All depends on where the thermostat is, and that can be moved if it makes sense to your needs. I like the idea of zoned heat, though I have no experience with it. I just close or open vents and doors depending on what current needs are.

--Vic

[trader4]

But here's the problem. You claimed that slowing down a blower doesn't necessarily reduce the air flow. If you were taking about the pathological case where the blower can't move air because it's cavitating, they you should have pointed that out. Because if that's the case, there is a problem that needs to be fixed with the system that has nothing to do with an ECM vs conventional motor. To do otherwise is just to spread FUD.

Who said anyone was screwing around with anything? In the current discussion, all I saw was Home Guy asking some very relevant questions about ECM motors, including those installed in modern furnaces at the factory.

So then Home Guy's point remains valid. Apparently the motor can't know how much air is actually flowing. Sounds more and more like it's just a multi- speed motor that will be more efficient in most applications, ie those with typical or better ducting. In the typical install, that equates to using 20% less energy. Now, if we don't intend to run our blower 24/7, instead using it only when actually heating or cooling, how much will that amount to?

The question of course remains if cost is the only issue, with typical use, will you save enough in electricity to recover the cost? I'm looking at quotes where it's $1000 more for a 95%efficiency furnace with a two stage burner and variable speed ECM blower, compared to one without those features. Clearly all that cost isn't due to the blower but it comes with it, without choice. Combine that with the exposure to increased repair cost for the ECM and drive electronics and I'm not sure of the value proposition.

If you have issues other than saving energy that the variable speed drive will help with then it's another story. But for me, I don't see that extra value.

Around here, NJ/NYC area, I'd say the majority are not. My house isn't. And I see plenty of new construction where they have dual zone systems, putting one furnace in an unfinished basement, the other in the attic, which is even worse if you keep air moving 24/7.

Also, not one person that's hawking the wonders of variable speed blowers even mentions the above points. It's obvious I don't have a finished basement and not one contractor said a word about it. All of them are spouting mostly what we call marketing BS. Like the variable speed blower in a 5 ton AC is gonna use the same electricity as a 40W bulb. That the furnace which is still rated at

95% AFUE, just like the single stage, is now going to be way more efficient. Both of those are fiction. There's some truth that the furnace will be slightly more efficient when firing at 70%, but from physics and what I've been able to gather, it's a small percentage, a couple percent at best. And around here, it's gonna be firing at 70% in the Fall and Spring, when I use the smallest amount of energy anyway. So the gas usage difference is very slight.

You dismissed all the above on the basis that there are lots of finished basements, so the heat lost by constantly pumping hot air through cold basements, garages, attics etc isn't an issue. I say it is.

Explain to us how it's possible to send air through typical ducts in the outside walls of homes when it's 20 outside and not have them lose heat. Maybe you've re-written the laws of physics. Actually it sounds like you have, since you say the air coming out is room temp or better with the burner off. How is it possible to gain heat?

I can take the two stage complexity and the ECM out by simply choosing to not buy it and still get a 95% AFUE furnace. And as to repair cost, he has a valid issue. Are you going to claim that the replacement cost of the ECM motor or drive electronics is the same as a conventional motor? I've seen plenty of stories here over the years of people paying $800 to replace them. If a plain old motor goes, I can replace it for $100. Does that mean all the technology in today's furnaces isn't justified? No, but IMO you can't lump it all together. It's like buying a new car that has headlights that autmatically adjust and react to the cars pitch up or down at any given moment, to maintain them perfectly pointed evenly ahead. A nifty feature? Yes. But when that system goes out, it sure isn't gonna cost the same to fix as a conventional headlamp system.

[Home Guy]

Mr. Snyder appears to have painted himself into a corner over the finer details of the operation of ECM motors and seems to just want to walk away from this conversation instead of admitting he's wrong or mis-informed.

There are several nation-wide HVAC retailers with websites listing prices for furnaces. I was looking at one a few days ago, and they listed various Goodman furnaces with various efficiences (from non-condensing to condensing, etc) and the price for the furnaces ranged from $750 to $1500 if I remember correctly.

Have a look at these retailers / wholesalers:

See if the furnaces you've been quoted on are carried on any of the above sites to get an idea of just how much your local contractor is over-charging you for the hardware.

I have a hunch that just like roofer's who over-charge you for the shingles, you'll pay a 50% premium for the hardware when you buy an entire package (furnace + installation) from a local contractor.

Your $1000 difference in the cost of a furnace with and without 95% /

2-stage / ECM is insane. Most 90+ furnaces seem to cost around $1000 judging by what I see on those sites.

See what your contractors say about just installing the furnace that you buy on-line. See if they balk and weazel their way out of doing that.

Your point about running the fan 24/7 is lost on a lot of people.

Your house loses heat through the walls, windows, and ceiling. Doesn't matter how much you insulate - the walls, windows, doors and ceiling are the containment envelope for the heat in your house. You're not going to loose heat through the wires or the plumbing.

And it's not just the basement walls (that's a red herring).

By running your fan 24/7, you're constantly forcing interior air to pass against the walls, ceiling, windows and doors, where the air will do it's best to either pick up heat (in the summer) or dump heat (in the winter) against those surfaces and tranfer heat to (or from) the outside. It's in the winter that this heat transfer is particularly of interested to us.

What you want is to achieve a still-air condition where there is no air motion inside your house. This condition will result in the least amount of heat being drawn off the interior objects (furnature, interior walls, floors, etc) and deposited against your exterior walls, windows, doors, etc. But with a forced-air system, you have no choice but to move air around and cause a breeze.

So while running a furnace 24/7 with the furnace dumping exactly as much heat into the house as the house is losing to the outside is (in theory) the most efficient way to operate, the very act of moving the air around inside your house is contributing to heat loss to the outside world. So it's probably the case that a furnace duty cycle less than 100% is more efficient at heating your house while conserving interior heat at the same time. I'm thinking more like 70% is probably where you want to be, and certainly to NOT run your fan at any time when your furnace is not on.

[Steve]

Legitmate contractors will not install *ANY* equipment that the customer has purchased off the internet for 2 reasons.....

1) Manufacturers warranty is null and void for any and all equipment purchased off the internet. 2) Legitmate contractors cannot and will not assume *ANY* liability for said equipment.

I charge what I do, because thats what it takes to keep my companys doors open, and still make a small profit after all of the costs, expenses, salaries, and taxes are paid. Here's a hint..... "The bitter taste of a poor quality installation will linger far longer than the initial sweetness of a low price."

[The Daring Dufas]

The finest equipment in the world is worthless if installed improperly. I'm sure you've come across heartbreaking installations of expensive systems that some hack put in and you have to break the bad news to a very nice customer.

TDD

[Steve]

The especially bad (dangerous) ones, I take pics of and forward to the city code enforcement and/or county planners office, and the state fire marshal.

[The Daring Dufas]

I was at a deposition last week where the defendants attorney was quizzing me about my training and where I got it. Nobody can supply the training I've had. I started out repairing window units in the early 1970's and self taught from there. My friends with all the wallpaper come to me and ask me about this and that because I've usually seen it. "Experience is a fools best teacher." Emerson. :-)

TDD

[Home Guy]

Steve used improper usenet style by unnecessarily full-quoting:

Where exactly is that written? Nice to see how you try to spread FUD over this.

The manufacturer has no way to know exactly how a given furnace was purchased, and it doesn't matter in any way, shape or form how a new-in-box furnace makes it's way through the wholesale-retail chain to the customer's basement.

Once there, installation by a "professional" contractor should satisfy all the critera for the factory warranty.

The customer would not ask the contractor to assume any liability for the equipment, only for the proper installation of said equipment, which should be totally acceptible to you since you are installing perfectly good equipment, perhaps exactly the same equipment that you sell to other customers.

Your cost structure is your problem.

It must be emarassing to you when a customer finds out how much you over-charge him for the same furnace that he can buy himself from these various vendors.

I'm separating purchase of the equipment from it's installation.

There is no rational argument that you can make against a home-owner sourcing and purchasing the furnace for himself, and then contracting you or some other HVAC company to install it.

Because at the end of the day, that's all you guys really do - installation. You don't make the furnace, it just passes through your hands on the way from the factory to the customer. So don't give us any bull-crap that the customer *has to* buy it from you. That's a very unprofessional way to operate.

[Home Guy]

The Daring Dufas used poor usenet style by improperly full-quoting:

You totally missed the point.

What's wrong with the customer buying a new furnace through one of those national retailers / wholesalers, and then contracting a local HVAC company to install it?

How would that result in improper installation?

The customer would save the 50%+ markup charged by the local HVAC company for the furnace.

[.p.jm.]

How about 'the warranty states that if installation is not done by a RECOGNISED contractor, there IS NO WARRANTY.' And no contractor who is 'recognised' ( IE set up and registered as a factory-authorized dealer or warranty contractor ) by a given brand is going to TOUCH your self-bought equipment.

Now, sure, Pedro's Heating and Air will be glad to put it in for you. When you try a warranty claim, you will find that you have no warranty.

When you buy something at Best Buy, and it's defective, do you expect Best Buy to stand behind it ? They didnt' make it, you know.

You idiot.

[.p.jm.]

Asshole - you really think you get 'wholesale price' like that ? Yeh, you probably think if a car dealership sells you a car at '$ 100 below invoice', they lost money on the deal. after all, they showed you on the invoice 'what they paid for it', right ?

Anyone who is actualy in the business laughs out loud at the 'Internet wholesale' prices for any parts or equipment. It's double what they pay at the local supply house.

[Home Guy]

Post a link to an example warranty, where it states exactly that.

So if you are a recognized seller and installer of Trane, and if I buy a new Trane furnace on my own, how can you say that you're not "authorized" to install it?

Pedro will handle the warranty work for me, because he wants the business.

Pedro will handle the warranty work for me, because he wants the business.

Besides, I thought these new furnaces were sooooo much more reliable than my POS 36 year-old furnace - right?

After all, according to you blow-hardts, these new furnaces with their electronics sensors and ECM motors are bullet-proof - right?

Looks like I touched a nerve with all you HVAC installer crooks.

[The Daring Dufas]

I found the "wholesale" prices to be very amusing. :-)

TDD

[The Daring Dufas]

No HVAC company will guarantee any equipment they don't supply. Me and my friends have installed used or new equipment supplied by a customer, usually commercial, with the explicit understand that nothing is under any warranty. You're not going to get any high end name brand equipment unless you go through an authorized dealer. If you do, the manufacturer is going to take action against whoever supplied the equipment when they find out. Your savings are an illusion.

TDD