New gas furnace/AC recommendations?

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I've decided to take my own advice and look in to getting a new natural gas furnace and AC unit installed before the $1500 tax credit runs out at the end of the year. Not much time left, I know. To get the credit, it has to be at least 13 EER, and 16 SEER. My old system is a 26 year old RUUD and I figure between the tax credit and higher efficiency saving energy costs, it's time to do it.
Anyone have any recommendations as to brands/models that they have had good results with or those to avoid? Any particular features? I'm thinking it's going to be worth it to get a high enough efficiency system to meet the $1500 tax credit, but probably don't need anything more than that. Any features you've found useful on newer systems and would recommend? Things like variable speed blowers, dual stage, etc? But honestly, the current one is fine in terms of comfort, can't complain about drafts, etc. The house is 3200 sq ft, current furnace is 150K BTU input, 4.5 ton AC. Location is coastal NJ, with high gas and electricity rates.
I know what one guy here will say, ie just keep running the old one.....
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On Dec 3, 1:46pm, snipped-for-privacy@optonline.net wrote:

I didnt know furnaces ran windows. Consumer Reports mag did a poll of about 22000 people years ago, the top results were suprising, you do have CR mag online, right. If I was looking for one it would be stainless steel heat exchanger not treated steel. If you over heat them ive heard they fail fast. Checking the temp just above the exchanger is something you should have set up and do. If it gets humid inside when temps are mild, to mild for normal AC, a Vsdc blower will do alot by running real slow and cycling the Ac only for humidity removal, if its set up right. Vsdc should also save you 15-30% on electric usage overall. The first generation untis failed within 6-10 years, ive heard but they redisigned the electronics so maybe they last now, you still need the longest warranty if you go with the fancy stuff. 10yrs is common and maybe 15yr warrantys are done now. 2 stage or modulating gas valves allow more even heat. With a high efficiency condensing unit you automaticly cut the size of overall btus needed by 10 to maybe even 15%. If you dont run it 24 hrs a day on the coldest days you might cut its size more. But if you do the setback or vacation alot recovery is harder. You could Diy it , save money, have no warranty and maybe be covered on savings. I think vsdc motor is 600, but im guessing on all numbers.
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ransley wrote:

Don't joke. Next year they'll be running linux or android.

So post them here.

Yes. Stainless for both the primary and secondary exchangers. Take a magnet with you to the hvac dealer's show room and test the units they have on display.

Correct term for vsdc motors is ECM. ECM motors are a crock of shit. Best you'll save is 100 watts compared to 1/4 hp AC motor, and less if you have 2-speed AC motor. Saving 100 watts at 10 cents/kwh is about $100 (that's 100 watts continuously for an entire year). Now subtract the electricity used by the furnace motherboard, and various other blowers and condensate pump. The extra 100 watts used by AC motors are dumped into the house as heat - which is what you need in the winter (and spring and fall depending where you live) so it's not all wasted energy.
Lifespan of ECM motor is 1/2 to 1/4 that of AC motor, and it's 4 to 8 times more expensive (upfront cost of furnace is higher, repair costs higher). ECM motors create EM/RFI on your household wiring, can interfere with tv and radio reception.
Now tell me how you're saving with an ECM motor.
So where are we?
1) Adding second stage heat exchanger to conventional (70 - 80%) furnaces from 30 years ago gives us condensing furnace (95% give or take) - which is good. I do like that improvement.
2) Using cheap steel for heat exchangers compared to furnaces from 30 years ago is bad. Using stainless is good.
3) Using electronic ignition is bad comprimize from cost/savings point of view compared to standing pilot light. No real need to use electronic ignition in modern condensing furnace.
4) Using ECM motors is also bad comprimize compared to 1/4 or 1/3 hp AC squirrel cage motor. *Actual* or *Net* energy savings don't justify extra cost and reduced longevity.
As a consumer, give me the choice of electronic ignition or conventional pilot. Give me the choice of ECM vs standard AC motor. Give me the choice of mechanical thermostat (in the furnace) to control gas valve and fan motor instead of electronic motherboard. Give me all stainless for the exchangers. If you don't give me ALL those choices, then I say that modern furnaces and the entire industry is a crock of shit.
Beyond the furnace itself, it's time to start ducting winter heat around the AC coils instead of going through them. You want efficiency? It's not efficient to blow air through coils when you don't need to do it during the winter.
It's also time to allow for spring/fall cooling by having ducting and gating that allows the furnace to pull return air from the outside, force it into the house, and gate the interior return air back to the outside. When ever you want the house cooler, and the outside air is cooler than the inside air, then why use your AC when you can draw outside air into the house directly?
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I dont know how to cut and paste yet but its 2008 CR magazine furnace survey
Ecm Vsdc, it can run at 100watts vs 375 for my 1/4hp, thats near 70% saving in slow mode, maybe near 100w less at high speed.
Who in the US pays only 0.10c per Kwh, you must live near a big Dam and get subsidised electric because im .18 and so is the rest of the US, many place are near 0.25 kwh.
You miss the point, its comfort or else you wouldnt even have a heating system. Vsdc can remove in low speed maybe 50% more moisture with minimal cooling so its great in humid areas, great for homes with uneven heat. It is about comfort, but can save the cost of the motor in electric usage over 6-7 years. That was my figure years ago at . 125kwh.
You have to know yearly hours run in heat and AC and a real Kwh cost to make any claim to it not paying back.
Lifespan, are you refering to the old or new redesign motor.
Electronic ignitions failing, so do thermocuples.
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Steve wrote:

How exactly do you improperly install a furnace?
If you are replacing an existing furnace, one that has been running for years in a given house and presumably giving satisfactory service, then how possible can you remove it and "improperly" install a new one in it's place?
What is meant by improper? That a water line is connected to the gas input line? That the upstairs thermostat is connected to the furnace AC power input? That the return duct and output air plenum are connected backwards?

How does the correct sizing of a furnace impact on whether or not the heat exchanger lifespan is impacted by being stainless steel or regular steel?

Would these be the same ductwork designed and installed by licensed contractors?
Would these be the same ductwork that was original to the homes in question - the same ductwork that somehow didn't manage to dammage or burn out the motor in the previous furnace - presumably an AC motor?
I'm sorry, but if my 36 year-old AC motor didn't burn out because of the size of my existing ductwork, then it's a crock of shit that the same ductwork is the reason why a new ECM motor burns up.
Blame the ductwork. When you have to explain to the customer why his new $4000 furnace is costing so much repair hassles, blame the ductwork.

You need to show you're a man by pointing out exactly which of my statements above are wrong.
I'm right when I say that:
1) ECM motor uses 100 less watts when running full speed compared to 1/4 hp AC motor running at full speed.
2) The extra 100 watts used by AC motor is dumped into the house as heat during the heating months, so it isin't exactly wasted energy from the point of view of the home owner.
3) You can't compare the energy usage of an ECM motor running 1/4 or 1/2 speed against a single-speed AC motor. If you want to compare the costs of multi-speed operation, then you must compare ECM with a 2-speed AC motor, and you must correctly estimate the amount of time (total hours per year) that the fan will be running at fractional speed.

Totally wrong, because you have to factor in the control or drive electronics that's powering the motor, and when you do, you'll end up with burned out transistors.

The efficiency of fractional horse-power ECM motors are (at best) 60%, while a 1/4 hp PSC AC motor will have an efficiency of 40% (if running at full speed). 1/4 horse power is about 186 watts, so an AC motor will use about 465 watts, while an ECM motor will use 310 watts. The difference (about 155 watts) would use 1,357 kw hours given a continuous 1-year run time. If the total electricity cost was 15 cents per kw hour, then that equates to $200 per year.
Now if you consider the case of a 2-speed AC motor compared with a 2-speed (or even variable-speed ECM furnace) and if you factor in that in a typical use-case that neither motor would or could be operating for up to 25% of the time, then the potential savings from using an ECM motor will almost certainly drop to closer to $100 per year.
Now if you factor in that the 155 watts of extra energy being used by the AC motor is given back to the house as heat, then you need to determine what that equates to in terms of cubic-feet of equivalent natural gas and subtract the cost of that amout of natural gas from your electricty bill to get the true additional electric cost by using an AC motor instead of an ECM motor.
While all ECM motors are capable of infinitely variable speed and can be implimented as such by something as cheap and easy as programming code in the controller, furnace makers charge a fortune for anything more than simple 2-speed operation. That is another crock of shit for this industry.

I could argue that a belt-driven fan with an AC motor with bushings is quieter than a direct-drive ECM motor with ball bearings.

Or so you think. There's no way that a home-owner (or even consumer reports) is going to know which units put out RFI, and which units actually give you what you pay for. Models change all the time - too fast for independant testing and analysis to have any effect or be useful for the buying public.

Which equates to 155 watts as I calculated above.

Be a man and tell me where I've said anything wrong.

We're comparing 30 - 40 year-old furnace technology with conventional furnaces. If furnaces cost proportionately more today in terms of % of disposable income then I should expect no less durability or longevity compared to the older furnaces. You seem to be an appologist for the industry by indicating that we should pay more and expect less.

Because standing pilot lights have been used for decades and have proven themselves to be reliable, safe, simple, and cheap.

The pilot light and it's thermocouple switch have proven to be an excellent design in terms of safety, reliability and durability for residential furnaces. Do you disagree? Do you have the balls to disagree?

Removing the electronic ignition and replacing it with a pilot-light and thermocouple does not constitute "removing a safety" device. Get a grip here.

See above. Best case savings is $200 a year, typical savings will almost certainly be less than $100 a year.
Anyone who lives in a climate zone where they expect to use their furnace at least 5 months out of the year will realize less than $100 savings in their combined electric and gas bill just by having a furnace with an ECM motor. Anyone who lives in a more temperate climate zone and runs their fan more often either alone or in conjunction with their A/C unit will come closer to the $200 in electricity savings.

We're talking simply about ECM motors replacing conventional PSC AC fan motors in residential furnaces. Motors that are part of other components (heat pumps, A/C compressors, dishwashers, clothes washers, dryers, etc) are another matter and have different cost/benefit arguments.

The single largest decrease in my energy bill that the furnace industry can give me compared to what I have now comes from the 2-stage condensing heat exchanger. Better airflow design, thinner materials, stainless, possibly better burner design, etc. All of that comes from better thermodynamics and materials - NOT ELECTRONICS.
The addition of electronics - particularly the electronic ignition and ECM fan motor, adds unnecessary cost and complication to the modern furnace with no tangible benefit to the home-owner and comes with additional medium to long-term cost of ownership costs and device down-time caused by component failure.

Screw the contractor. I want a box that will sit there and work year after year. It's no consolation to me that a repair tech is just a phone call away. I'll take reliability and durability any day over repairability. Especially when it comes with lower up-front costs (no electronics). And in this case, I'm not even sacrificing repairability. Low tech = high repairability.

I can install myself any furnace. That's not the point. I'm just bitching about they choices that furnace makers are making when they design / build them.

When you have electronic ignition, you HAVE TO HAVE an array of electronic sensors to make it safe. Having those sensors and electronics comes with a price - a hit to cost, durability, reliability.
When you have a standing pilot light with electro-mechanical thermocouple and gas valve, you don't need sensors or electronics, because it's inherently safe.

We're not talking about the thermost here. I can have the most advanced, computer-controlled thermostat I want upstairs to control my 35 year-old furnace, yet still have no electronics *in* my furnace. Understand the difference?
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I will interject my $.02 here...

By having too high of a TESP (total external static pressure.

Older furnaces had a lower CFM rating, hence they have a higher temp rise for a given output BTU rating. Newer equipment for effeciency's sake have thinner heat exchangers (less metal thickness to push the heat through) that can't tolerate the heat without cracking hence they have a higher CFM rating, hence more TESP by trying to shove more CFM through the existing ductwork.

Sometimes, just go to the hvac-talk.com wall of shame and see all the bad ductwork installations, many being a "ductopus" using flex duct.

Yes, and here is why. Your average PSC or split-phase induction blower motor on high runs at a fairly constant speed (a 4 pole motor can only speed up from its rated speed, usually 1725 RPM to just under 1800 RPM @ 60Hz). With a centrifugal blower (squirrel cage) the torque load on the motor is directly controlled by the amount of air flowing through it (ande vice versa), hence as you restrict the airflow (increase the SP) say with undersized ductwork the blower unloads. Less torque at the same speed means less HP (HP=torque in ft-lbs x RPM / 5252) hence less motor watts. An underloaded motor is less effecient but lasts longer. Too little TESP on a system with an induction motor can actually overload the motor, hence why old systems that had belt drive blowers usually has a variable pitch sheave on the motor. The belt ratio hence wheel speed was adjusted to run the motor at full load with a new system. As the ductwork and/or filter got dirty the TESP went up and the motor unloaded some.
Now here is where it gets tricky, ECMs as used on indoor blowers are constant torque NOT constant speed. The shaft torque is held constant hence the airflow is held mostly constant. Increase the TESP on these systems and the blower speeds up either till the torque/airflow goes back to rated or till the motor hits its top speed limit. More RPM X same torque / 5252 More HP = more watts. More watts x same airflow means hotter electronics hence shorter life. Add in a plugged filter and the poor little motor runs its little heart out at max speed with little cooling airflow till it burns up.

Explained above.

As said this depends on TESP. At high TESP the ECM can use more watts than the PSC.

Electric resistance heat is usually more expensive than gas heat and in the summer it is just more sensible heat load on the evaporator hence more watts still loses.
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..

A while back I came across a study done on the savings of ECM blowers in residential HVAC applications segmented by geographic regions/climates. One key result of that study, which I didn't expect and I believe is reflected in what you say, is that how much energy one saves depends to a large extent on the duct work. The greatest savings came from ideal duct work, ie lowest pressure. Next was good duct work, which also used significantly less savings. Duct work they classified as typical still got savings, but much more modest, maybe 15- 20% in electricity cost. However if you have poor ducting there can be no savings or even a net loss of up to I think about 10%. The energy savings also obviously depends on the climate.
But I think HomeGuy has a vaild point, at least to some extent. Whether you can recover enough in energy savings on an ECM versus the increased upfront cost as well as the real potential for higher repair bills is questionable. I've seen horror stories here of the ECM electronics fried by power surges for example and a $600 bill But I've never heard of a conventional furnace blower failing from a power surge. Also, I think you'd agree that if improper duct sizing can screw it an cause it to fail, it's entirely possible that some contractors who don't know what they are doing will result in the motor failing at some point. And if that point is after the warranty is up, then you're screwed.

This same faulty logic is frequently applied to water heaters with claims that the standby losses from storage tank models helps heat the house. For some reason, they completely forget that for most of us with AC, that gain turns into a loss in the summer.
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On Dec 6, 4:22pm, snipped-for-privacy@optonline.net wrote:

m...
If a power surge fried the blower it would have got the control panel first. With any new unit you should be doubly sure its surge protected and well grounded since you will have alot of electronics. When I got my install they offered to somehow test my duct airflow, thats where shopping for the right pro is important. I heard those motors were redesigned a few years ago to separate the electronics from the heat of the motor, since the electronics were what failed and now the motor and design has finaly matured.
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snip
snip
It is quite possible. A belt drive blower could put up with an awfull lot

Not necessarily - but if the installer does not do the temperature rize test and properly set the motor speed, you could get a failure due to improper installation.

You underestimate the difference in efficiency between a standard induction motor and an electronically commutated DC motor, PARTICULARLY with multi-speed AC motors. At lower speeds ECMs can save over 60% of the electricity used by PSC motors. For example, in low speed circulation a typical PSC furnace motor will use 350 to 500 Watts while an ECM will use 75 - 125 W.
You need to read the entire study at: http://www.nrc-cnrc.gc.ca/obj/irc/doc/pubs/nrcc38443/nrcc38443.pdf , but an interesting part is the following - with the same airflow,
"The power use of the ECM and the PSC motor were measured in one-time tests using a Nanovip power meter. The ECM used 16.5 Watts in circulation speed and 284 W in heating speed, while the PSC motor used 350 W in circulation and 490 W in heating. Thus, the ECM used 58% as much as the PSC motor in heating speed, but only 5% as much in circulation. The ECM’s flow rate was almost identical to the PSC’s in heating speed, and was 47% of the PSC’s in circulation speed."

Ditto
The National Research Council study quoted shows 206 watts difference on high speed, and 330 watts less on low speed.

Except when running the AC - and gas is cheaper than electricity for heating.

Or do as the National Research Council did, read the study - very comprehensive testing.

Actually, they are finding the ECM to last at least as long as the AC motor in many tests. (in part because they run cooler). The motor control electronics are the least troublesom of all the controls on modern furnaces. SNIP

I do. I've replaced too many thermocouples on standing pilot furnaces - and NO electonic ignitors so far on the new furnaces. Average lifespan of my thermocouples has been less than 7 years (5 in 22 years on my own furnace, and 5 in 7 years on my friend's gas boiler) I'm on #3 on my water heater as well. This is, I believe, year 8 on the electronic ignition furnace.
SNIP

The blower in my furnace runs at low speed 100% of the time that the furnace is not running on high for heat or a/c. (for air cleaner and overall comfort) If the furnace NEVER kicked on, the ECM saves me 2890kwh per year. (330 watts X 24 hrs/day X 365(90800 wh).That's $232 at $0.08 per kwh. and that's not counting the savings when the furnace is actually running. And the actual cost of electricity is more than $0.08/kwh here when you add in the distribution charges and everything else, and throw on 13% HST

Actually, IF the condensing furnace is 7% more efficient than the equivalent non-condensing furnace, (97 vs 90) the fuel savings will be about 8%. With my total annual gas bill of $700 (part of which is my water heater) my maximum total gas savings would be less than $56 per year. Not a very attractive payback, particularly if I end up replacing the secondary heat exchanger in 10 years.

SNIP
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When it comes to discussing the pro's (or perhaps the lack thereof) of ECM motors for use in HVAC air handler systems, I've found that this document is very informative:
http://www.buildingscience.com/documents/published-articles/pa-ecm-eficiency/at_download/file
I have pasted the conclusions of that document below. It basically says that the benefits of ECM motors are lost in installations with high static pressures (and something that I bet a lot of home-owners don't want to fork out money for is to re-do the duct-work in their homes).
Perhaps someone else can explain why the flow characteristics of a duct system is described in terms of the back-pressure it generates instead of speaking directly about the RESISTANCE of the ductwork, even perhaps putting a number on it (which surely can be done, given that we might know the CFM and the air pressure at the input side of the duct, and assuming the pressure at the far end is zero). When someone is talking about high static pressure, they are essentially saying that the duct system has a high resistance to flow (caused by any number of reasons - closed or blocked vents, small-diameter ductwork, long runs of small-size ducts, turbulence caused by right angles, filter too small or too dense, etc).
Which could be why my idea that the gating of furnace output around the A/C coils is not appreciated as something that can reduce airflow resistance (ie - reduce static pressure).
As someone who's been living with and has experienced HVAC systems with single-speed AC fan motors, I really can't appreciate the need for a variable-speed fan motor. All this discussion about how PSC motor efficiency drops to 15% - 30% when used at low speeds is a real mystery to me - are there really furnaces out there that have the necessary electronic controllers that will use PSC motors in such a variable-speed capacity? Why no real discussion about the efficiency of 2-speed AC motors?
I also don't understand how running a fan at low speed is better at humidity removal when the HVAC system is in A/C mode - yet ECM makers make that claim.
Claims that ECM motors are just as reliable as PSC are also a crock, given that none of them could possibly be in service yet for 30 to 40 years as is the typical PSC motor to even begin such a comparison.
Youtube video showing badly-behaving ECM motors:

http://www.youtube.com/watch?v
dXPVZfrRk
http://www.youtube.com/watch?v=5MIgb_2LwH4&NR=1

These ECM motors look really flimsy - like the 1/8 hp electric motor I have on my roof for my attic fan. Sorry - I wouldn't want something that wimpy in my furnace.
Apparently they are somewhat succeptible to lighting strikes (lightning doesn't have to hit your house directly to dammage the electronics in your house). I guess your entire furnace is more succeptible to lightning when it's got it's own computer. Another strike against the modern furnace.
---------------------------------------
Conclusions:
The main conclusion that we would draw from this study is that although the use of an ECM has the potential to reduce fan electrical power draw, much of the benefit is lost in systems with excess static pressures. A full analysis of this problem was done by Lawrence Berkeley national Laboratory (Lutz et al., 2006). In other words (as in many cases in the building industry) the benefits of high technology can be defeated by poor design and faulty installation or implementation. Problems can include excessively constricted duct designs and installations, restrictive return plenum fittings, or excessively restrictive filters (see Is There a Downside to High-MErV Filters? HE nov/Dec 09, p. 32).
However, with better designs, air handler efficiencies can be improvedsignificantly beyond the typical values assumed in previous work (that is, 2.5 CFM/W or 0.4 W/CFM). This is especially true when a given air handler is used at the lower end of its speed range. For instance, a 1.5- to 3-ton unit being used at 2 tons air flow at 0.5 IWC static pressure has an efficiency in the range of 3.7 CFM/W (0.27 W/CFM). Of course, reducing air flow for a given size of outdoor unit can have negative consequences, such as reducing overall efficiency (SEEr and EEr). But this factor can provide additional ammunition when arguing for tighter sizing of cooling equipment, and/or two-stage equipment with a variablespeed air handler.
In other words, if you can keep the air flows down (all other things being equal), you are giving your ECM a better chance to achieve high CFM/W efficiencies. The measurement of air handler efficiency is relatively simple; it can be done mostly with gear that a home performance contractor is likely to have. an air handler powered from an electrical receptacle can be quickly measured with a plug-in power meter such as a Kill-a-Watt. However, power measurements are more time-consuming if the air handler is hard wired. But overall, increasing the data set of installed ECM air handler efficiencies could be very informative, as would measuring and recording the operating external static pressures for these units.
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LOTS of furnaces and AC systems with multispeed PSC motors - and they are terribly inneficient at low speed. And there is virtually no "electronics" involved. On my old furnace it was just a relay - the fan ran on low speed continually untill the furnace called for fan, when it kicked a relay that put the power to the high speed windings instead of the low speed.

The AC runs the fan at HIGHER speed than the furnace on my new system - but runs the fan constantly at low speed when the AC or furnace are not calling for circulation.

My PSC lasted less than 20 years. It was a 1/3hp belt drive - replaced it with a 1/2 HP

Some are wimpy, some look just like a typical PSC motor - and the PSC direct drive motors WERE wimpy - and many didn't last 10 years.

IN ALL cases, the benefits of high technology can be defeated by poor design and faulty installation - doesn't matter what field you are looking at.

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PSC blower motors are not really multispeed at all. All the extra speed taps are are taps on what acts as an internal autotransformer. High is rated voltage and the lower speeds just effectively undervolt the motor. Run a typical 1050 RPM 6 pole PSC blower motor on high sometime and measure the voltage from the low tap to neutral, it is usually around 170 volts AC depending on the motor.
There are true 2 speed induction blower motors that are wound as both a 4 pole and a 6 pole. The high and start windings are 4 pole so the motor always starts on high but if it is hooked up as low it switches the power from high to low as it starts using the same centrifugal switch that cuts off the start windings. When not running these motors will show a direct short between the 2 speed wires.

Less airflow allows the evaporator to run colder hence it cools the air more and the leaving air has a lower dew point hence a lower humidity % when warmed back up by the house/building..
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http://www.buildingscience.com/documents/published-articles/pa-ecm-eficiency/at_download/file
Exactly, and this applies to *ANY* type of blower motor

Your idea if "gating" around the coil will cause more resistance to airflow becaise of the right angles, and induced turbulance than just going straight through the coil..... this is assuming that your using a coil that is designed specificaly for that furnace (OEM).

There is no benifit with a 2 speed PSC motor, other than it has 2 speeds, as compared to a single speed PSC motor.

It slows down the air passing the evap coil and allows more moisture to condense on the coils to increase humidity removal.

None of the "new" fractional horsepower motors will last 30 to 40 years anymore, 10 - 15 years is a good lifespan. As a rule, none of them have oil ports for lubrication, and *most* of them have sleeve bearings, not ball bearings.

You don't have a choice anymore.

Your furnace is no more succeptable to lightning or power surges than any other appliance in your home that has a circuit board in it.
Your going to be dragged into the 21st century whether you want to or not. Get over it

This means that your ductwork will have to be checked for correct design and airflow. If your too cheap to pay have it done right, then there *WILL* be consequences, and its going to hit you right in the wallet in the form of failures/repairs, higher utility bills, and lower comfort levels.

Your *STILL* have to have the ductwork and system sized for your home.

This is why you need to get a *competent*, licensed, insured, professionally trained HVAC technician to do the job. One who can and will do the calculations, and take the measurements to insure that everything is correctly sized and operating at peak efficiency............ or you can call "Billy-Joe-Jim-Bob" down the road, or try to DIY. Either way, your going to get what you paid for.
There is a reason that the very best techs do 5 - 7 semester hours a year in continuing education and training. your not *JUST* paying for a guy with a ticket book and a truck, unless your looking for the lowest price.
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wrote:

Needs to be dragged into the twentieth first, before the twenty-first

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Good point.
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http://www.nrc-cnrc.gc.ca/obj/irc/doc/pubs/nrcc38443/nrcc38443.pdf
yes anyone interested in this subject should read that...
and take note that the study system had the blower running 100% of the time. When the furnace was not heating, the blower ran for circulation. and the ECM motor ran much sloer in circ mode compared to the standard blower so there was much less circulation and not surprisingly less energy was used.
But if you turn the blower OFF when the furnace is off like most real people do, then it is less relevant.
and also note the part where the ECM blower caused gas consumption to increase..
I would say the facts are presented in this paper but the writer slanted the conclusion in favor of the ECM.
Follow the money...
Mark
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Whats obvious is you are doing everything you can to put down Vsdc motors and modern electronics for no good reason. Its future is here, live with it.
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wrote:

The blower speed was adjusted to provide the most efficient heat transfer - and actually the best air flow as well. Running a squirrel cage fan too fast can actually REDUCE circulation. I think that was also explained in the article. That's also why restricted ducting is such a big deal.

MOST people turn the blower off??? Not up here. Running the blower on low speed keeps temperatures even, and makes the air filter a lot more effective.

That was also explained - and I mentioned that in an earlier thread - the higher efficiency of the blower means more gas is required - but the cost per therm using gas is a lot lower than the cost per therm for electric, so it is still a net saving.

In the case of the National Research Council there is no money to follow. They are neutral, and not funded by manufacturing or marketing companies.

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On Dec 8, 5:53pm, snipped-for-privacy@snyder.on.ca wrote:

I would bet 90%+ of the HVAC installed in the USA runs the blower only when the furnace is heating or the AC is cooling, not 24/7. In a typical house with an unfinished basement or crawl space, I would think running it constantly would be a significant waste of energy from two standpoints. One is that it obviously uses a lot more electricity. Second is that while circulating all that air around you are running it through the basement or crawlspace, attice, etc that is unheated and you are losing heat through the duct work on each pass.
With a properly designed system, I don't see the need for constant circulation.

From the research I've done, I've concluded that the ECM motors are a mixed bag. In a typical house like mine (note that means running it only when heating/cooling), you might save 20% on electricity. I would pay some extra $$ for that. However compared to a regular motor, you have the issue of potentially higher repair cost, ie $700 bills instead of $100 due to the increased cost of the motor as well as the electronics to run it.
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On Thu, 9 Dec 2010 05:42:21 -0800 (PST), snipped-for-privacy@optonline.net wrote:

You don't see the need for it, but the VAST majority of new furnace installations in ontario are set to run the blower on low, constantly. All 3 contractors we contacted for quotes for my daughter's furnace (multi-story condo) strongly recommended it.

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