Either one.

The 13 SEER is less efficient, the 15 SEER is probably a 14 SEER and because size is on the small end at 2.5 Ton paired to the var fan coil the SEER on those configs go marginally higher.

Just realize the var fan coil is likely an ecm motor and those motors are notorious for not lasting that long / made in Mexico or China. Due to supply chain supply problems getting these types of parts is nothing short of a fiasco.

That said what kind of fan coil is being used for the Carrier option? They all use ecm or variable speed type motors in new equipment.

Due to that the 13 SEER may be closer to 14 SEER at that sized config. (SEER rating achieved is a number based on matched parts that were tested in a lab.) Configuration / design and a number of other factors will determine what SEER you actually achieve with ANY configuration.

Due to 2 month per season use, you will never recoup the difference in the cost of these configurations. Not even close.

Both are a rip off. Keep looking!

"Just realize the var fan coil is likely an ecm motor"

I thought ECM motors are now required in new equipment?

ecm stands for electrically commutated motor.

You could argue that the varible speed motor is an ecm.

The difference is what I like to call the original variable speed motor is a motor + module bolted to the end of the motor. ( in some varieties I seen the modules off the motor and mounted in an electric panel)

An ecm is a motor and module all in one. I call these ecm because they came later and that's what the mfg's called them. lol.

The move in terms of new equipment was to eliminate the psc motor or permanent split capacitor.

The ecm's (both types) still have capacitors. The difference is they are internal to the motor or the module in the case of the earlier variable speed motor that sepatated the module from the motor.

Mary I will keep it simple, the 15 Seer A/C will save about 10% in electrical costs over the 13 Seer unit.

Ray, it looks to me you may not know what an ECM motor really is. The motor is a brushless DC three phase motor with a permanent magnet rotor, and is completely different than a PCS motor powered by single phase AC power.

The capacitor in the controller end of a ECM motor is for the rectification of AC electricity into DC electricity and does not serve the same purpose as the capacitor on a PCS AC motor. The control module on the end of the ECM motor not only rectifies AC to DC but also converts single phase to three phase to operate the motor. I hope I'm misunderstanding your post and you do know what and how a ECM motor works, right? And please explain what a "var fan coil" is because I'm stumped, or was this a typo?

Elmer, again your contribution to this discussion has little to offer, and as is usually the case in technical categories, but it appears you are confused.

No motor is banned, or required to be used in any furnace as long as it meets or is less than the specific watts per Cfm values set for each of the 9 product classes of furnace fans specified in the final rule by the DOE for residential furnace fans. The manufacturers of these 9 product classes can use any motor they wish as long as it meets the watts per Cfm using the uniform testing procedures set in 10 CFR part 430, subpart B, appendix AA 10 CFR Appendix Aa to Subpart B of Part 430 - Uniform Test Method for Measuring the Energy Consumption of Furnace Fans.

The rules do not apply to any other part of the HVAC system and only the furnace fan's of the 9 product classes so Condenser cooling fans are not included.

And please explain what a "var fan coil" is because I'm stumped, or was this a typo? (don't quit your day job--- ha ha)

If you would read the whole thread starting with what the OP said...

The estimate reads ”2.5 ton var fan coil ECM AHRI#9252902 SEER 15 EER 12.5 BTUH 28000.” Total cost: $13,132.

It's an ecm var or short for variable fan coil or electric AH as in air handler.

The capacitor what it's used to for in this instance doesn't matter. The motor as in psc or the module however it's attached to the motor needs it to operate. So what difference does it make? none.

Wait Let's ARGUE.....

It will fail / it can't be replaced. -- you replace it by replacing the motor or module, but just replacing the module isn't truly wise. That is a mile in my shoes sort of thing.

I know lets make it more complicated and attempt to try to do a job we don't really do...

-------------------

The manufacturers of these 9 product classes can use any motor they wish as long as it meets the watts per Cfm

Common knowledge that isn't so common in the HVAC realm is that "psc" type motors are cheaper motors / less efficient. But last longer due to a variety of reasons.

Goodman is often considered cheap equipment so a simple and easy click to their website of furnace product offerings what do we find? (any furnaces with psc motors? uh no)

Every single furnace they offer is none other than ECM. The two that don't have the ECM that are on the top of the page in limited supply have the variable speed motor. Look back how I talked about them?

You can't buy something that isn't made any longer... because? you voted and maybe partly because maybe you didn't vote?

Go ahead take a look tell me where you can buy a furnace or AH with a psc motor in it new from a manufacturer since you're so interested in trying to do a job you don't do.

Goodman furnaces all ECM motors except 2 varible speed furnaces

Pick any manufacturer you want look for that mystical psc motor. They still make the psc motor, that isn't the argument. The argument is you can find them in a NEW furnace or air handler.

"Elmer, again your contribution to this discussion has little to offer, and as is usually the case in technical categories, but it appears you are confused."

There was no contribution, it was a question.

You can be sure your reputation is known to regular visitors to this and other forums. I usually ignore you but thought your misunderstanding of my words deserved a response.

Ignore turned back on.

@G, I read something about Inverter controlled PSC motors. I believe it was a Lenneox rep at the public hearing for the rule change by the DOE that mentioned ECM's under high static pressure consumed more power than the PSC motors they were replacing. The DOE agreed but ignored this fact.

"Ignore turned back on." Such a drama queen aren't you so just skedaddle back to the kitchen table with the other ladies.

@outpaientzero

Anything with high TESP can consume a ton of power. ECM motors don't consume nearly as much power as a PSC, though.

Anecdotally, I did some work on a home w/ some older bryant A/Hs with PSCs, in undersized ducts. The PSC was pulling a lot of power.. like 390W just to operate the PSC at 0.9 TESP (clean coil, no filters too.. lol)

We do have some newer stuff coming out soon, one brand is coming out with an A/H to log/record the TESP on the A/H itself and relay that data to the Tstat (comm only, though).

"Pick any manufacturer you want look for that mystical psc motor. They still make the psc motor, that isn't the argument. The argument is you can find them in a NEW furnace or air handler."

I'm confident you won't be embarrassed by it, Ray, but Bosch makes just such a system! Yes, Bosch! It's known as the "Bosch IDS Light Heat Pump." It's a low-cost system that pairs an inverter-driven compressor with a fixed-speed air handler driven by a PSC motor. You can read about it here:

https://www.businesswire.com/news/home/20220801005110/en/Bosch-Thermotechnology-Introduces-New-Inverter-Ducted-Split-IDS-Light

You've been hoist with your own petard once again. Somehow you'll spin this into something even more entertaining.

I'm confident you won't be embarrassed by it, Ray, but Bosch makes just such a system!

You'd love that Charles wouldn't you?... but well I'm not because this situation has hoops. See I call everything like I see it.

Because? I go back to that same job I did 5 years ago, 8 years ago, 10 years ago etc.

I'm gonna have to get parts for that machine (they all come from China currently). The other gotchya is this is an AH. If you have a gas furnace like upwards of 95% of my customers -- the furnace already exists. That is my market. Electric AH usuage in my market isn't that common. They exist but no where near the numbers of gas furnaces. If you have a gas furnace you don't need an AH (air handler).

So I am perfectly fine with this that you found. You pay a premium for the Bosch and the number one reason to go that route is that it will pay you back. The 15 SEER IDS lite doesn't make sense there are other better ways to cut costs than going with a more expensive machine that won't pay you back like the IDS 2.0 20 SEER will.

Why would you pay extra for a unit in the IDS lite that won't pay you back as well?

Currently it's not likely you find this machine in my market. Vapor ware... it's not due out until late 2022 even then it's not likely to be a system heavily stocked for my market if at all.

See here in picture below the unit isn't available. Why I don't comment on vapor ware? it doesn't exist -- you can't get it. Who is embarrassed? not me. ha, ha. Nice try though, Charles.

Ray,

I've concluded that houzz.com makes up the majority of your continuing education. Trade "professionals" shouldn't be learning what's available in their industry from home builders or homeowners on houzz.com particularly when the products are from the trade "professional's" favorite HVAC equipment manufacturer.

Charles I knew the IDS Lite was coming.

Now let's argue about what I know versus what you think I know?

Look how far you've gotten with thinking like that. Carry on. ha, ha, ha.

"Charles I knew the IDS Lite was coming."

It's not IDS Lite, Ray, it's IDS Light. I don't for a minute believe you would have passed up an opportunity to advertise the latest and greatest thing from Bosch even if it wasn't yet available. And if you knew it was, why would you challenge houzzers they couldn't find a PCS motor in a new furnace or air handler? Are you in the habit of jerking everybody around?

And if you knew it was, why would you challenge houzzers they couldn't find a PCS motor in a new furnace or air handler?

Only for you Charles, only for you.

Yes indeed, I found the specs for the IDS light air handler with the motor type used for the blower as PSC. Model BVA-36WN1-M15. Description.

Bosch Air Handler Unit, Vertical, Series: A Series, 36000 Btu/hr Nominal, 208/230 VAC, 1 ph, 60 Hz Power Source, 3/8 in OD Liquid Line, 3/4 in OD Suction Line, 15 A Fuse, 18 x 20 in Filter, Wired Control, R-410A Refrigerant, PSC Motor, 19-5/8 in W x 21-5/8 in D x 46-1/2 in H, Import.

Specifications

I can't find specific data on the motor or how it may satisfy DOE efficiency mandates but it's obvious it does or they couldn't sell it. Available and sold in the USA.

@kevin9408,

I could be wrong, but I believe the DOE mandates for motors you are referring to apply to residential furnaces.

@Charles Ross Homes Here is the DOE final ruling, and yes the rule applies to blower motors for 9 classes of furnaces.

FWIW Nidec, Genteq, Mars all sell PSC -> ECM upgrade kits.

"Go ahead take a look tell me where you can buy a furnace or AH with a psc motor in it new from a manufacturer since you're so interested in trying to do a job you don't do."

For the sake of clarity, Ray, you can buy air handlers with PSC motors from Bosch. If you need help with more sourcing of HVAC stuff, just ask here on houzz.com

For the sake of clarity Charles, I have never once asked for your help.

I may have asked you questions that I already knew the answer to... but you never answer any of those questions anyway.

Like this as an example on this thread:

Goodman is often considered cheap equipment so a simple and easy click to their website of furnace product offerings what do we find? (any furnaces with psc motors? uh no)

Instead you go running around in circles looking for AH's with psc motors. When my HVAC market consists of 95% gas furnaces. An air handler won't work for those... for more than one reason Charles.

Why would I run around looking for a PSC motor for something I can't use any way. WHOA stop using logic Ray.

List the reasons why an AH won't work for a home that has a gas furnace? There's more than one. (retrofit)

Give me some help Charles answer the above question. (realize this is me antagonizing Charles for things he likes to pretend he knows. I don't need an answer I determined this on my own over 28 years ago.)

But it's so much fun imagining what I may or may not know. { find a job that pays you. ha-ha}

Ray, you challenged houzzers to find a furnace or air handler currently available with what you termed the "mystical" PSC motor. I took that as an information need which I happily satisfied as did others. Turns out your favorite manufacturer, Bosch, offers new heat pump systems which include air handlers with PSC motors. I could be wrong, but I imagine your market includes lots of demand for heat pumps so you can probably make use of them. By the way, the Bosch IDS Light Heat Pumps aren't "vapor ware." Some stocking dealers have them in inventory now. If you can't get them, then I suspect either your market or your business or both aren't a priority for Bosch. You'll need to take that up with them. And if you need additional information, you need only ask.

"ways to cut costs than going with a more expensive machine that won't pay you back like the IDS 2.0 20 SEER will."

This is just laughably silly.

It's indeed laughable coming from an HVAC "pro."

The Bosch IDS Light heat pump is an offering which provides many of the benefits of more expensive inverter-driven systems (its compressor is inverter driven) without the sophistication of a variable speed air handler and associated controls. By pairing the two, Bosch is able to dish up the IDS Light as the lowest cost variable-speed heat pump on the market. It's just the kind of upgrade someone might make from a single-stage or two-stage heat pump to get enhanced performance of a variable speed compressor at little or no incremental cost. I think it's well positioned in the market and should have competitors chasing it if they can deliver on reliability.

Homeowners will see better savings on energy bills by fixing insulation problems, leaky ductwork, etc. The ROI on those items are much more immediate - and significant - than telling people 'You'll save more money with Sales EER 20!'

A properly designed/sized system compliments the insulation work. Plus, I like to design ducts to be slightly oversized to keep static pressure down :-D

"Plus, I like to design ducts to be slightly oversized to keep static pressure down :-D"

True, but you've got to be careful not to go too far or air velocity into the room is too low and you get warm/cold spots.

No kidding.

Nope, not kidding.

Homeowners will see better savings on energy bills by fixing insulation problems, leaky ductwork, etc.

Absolutely these things have to be done too. In terms of what you will save or won't save comes down to how much you run the machine.

In hotter climates we run our AC 9-10 months of the year. So because you would have to do those other things anyway plus the cost of a new machine, plus how long you plan to live in that house.... if you only use the machine 3 months of the year you're not upgrading to this machine to recoup the whole cost. You're not likely to get there, but higher electric rates north of 14 cents per KWH it could recoup the difference of what you would pay for the entry level machine. (Some people choose something because it's what they want. I suppose comfort related things are no different.)

This is why I said the Bosch Inverter isn't for everyone. You're not going to recoup the savings over night. If you're not planning to stay in that home long term you won't recoup it.

If you save $100 a month 3 months of the year. AND you save $75 a month another 3 months of the year AND $50 a month another 3 months of the year. (9 month example) How much is that a year? 300+225+150 = 675 x 10 years. 6750. x 15 years = over 10K. This example assumes utility prices don't go up in that time.

3 month term at $100 month = 300 a year. 3000 by year 10. Is that the difference of the entry machine? by year 15 you're at 4500. A cooler climate you won't hit full payback. At that point the decision isn't entirely about paying you back it's about what it does for comfort factor.

The Bosch IDS light that Charles is barking about isn't available it was due out late summer 2022. It's novel that Charles was able to find something on the internet, but that's not the same as it being available and putting a hand on it.

Bosch anything is in tight supply. If you want it you better buy it before someone else buys it and you have to do without. Otherwise you live with regret. Or cooling envy.

Here I sit in my office this morning with 40% RH. (relative humidity) in a humid climate no less. (no dehumidifier, just the Bosch Inverter controlled by a 4 zone HVAC system. For many it will be a decision based on a feeling someone desires. Every house is different, every person is different. The temp in this room this morning is 77F. (I run the zone next door to this one to 72F while I sleep.)

I'm not here to sell you just anything. I am here to sell you what is important to you. You are unique. I know that if I remove just 5% or 10% RH from what your current AC system does you will be that much more comfortable. If you're comfortable you're happy.

It doesn't help someone in Minnesota? They came here for options. Whether these options are available in Minnesota? I don't service that area.

I service the Katy, Texas area.

"Absolutely these things have to be done too. In terms of what you will save or won't save comes down to how much you run the machine."

Nope. The savings from better air sealing and insulation isn't limited to that portion of the year when air conditioning is called for. They save money in heating season as well. And they provide other benefits such as minimizing infiltration of allergans and humid air and help to keep the home cleaner and more comfortable.

"The Bosch IDS light that Charles is barking about isn't available it was due out late summer 2022. It's novel that Charles was able to find something on the internet, but that's not the same as it being available and putting a hand on it."

There's a wide, wide world outside Katy, TX, Ray. You might want to give the folks at Magic Touch Mechanical in Mesa, AZ https://airconditioningarizona.com/ a call and find out how they are able to have the Bosch IDS Light in inventory. I found them when I did a google search for residential air handlers with PSC motors. Ironically, their web site made it clear that IDS Light units from Bosch are configured that way.

I don't pretend to be something I'm not. So there's that to keep in mind as well.

A builder in VA can't help you either. (circular logic absolutely free courtessy of the internet.)

ha, ha.

@Austin Air Companie

The only positive I can see about higher seer units the larger coil area. Head pressure is kept down, keeping the compressor happy.

G,

head pressure is only down mildly on high SEER still well above R22 pressure. The coil area on the Bosch Inverter is probably one of the smallest condensers on the market, considering what it does and how it does it.

Some of these condensers made these days are ridiculous, nearly 5 ft tall can't even fit them in my service van. Ruud / Rheem 16 SEER the thing is a behemoth. I don't know what the engineers were thinking when they made that beast. Most places you'd have trouble installing it, let alone getting it to fit in your service truck.

Typical head pressure on Bosch usually in the 330 psi range depending on heat load / how hot it is. On say an Entry level 14 SEER unit the head pressure could be up near 400 psi and still be considered ok depending on heat load / how hot it is.

Compared to R22 -- usually 200 to 250 psi head pressure.

"I don't know what the engineers were thinking when they made that beast."

It's not too hard to infer that they needed to add heat transfer surface area and wanted to keep the footprint of the condenser unit the same or nearly the same. Altering the footprint of a condenser unit would limit its suitability as a replacement for existing units.

I'm sure HVAC manufacturers would appreciate your feedback on their designs. Just give 'em call and ask to speak with the director of engineering.

"Ruud / Rheem 16 SEER the thing is a behemoth."

Or, as Scorpio said in the movie, Dirty Harry, "My, that's a big one!"

Specification sheets on I find on current Ruud and Rheem units, 16 SEER, 17 SEER and up to 20.5 SEER state heights of 27, 31, 35, 39, 45, and 51 inches depending on the specific product line and capacity. 51 inches is 3 inches more than 4 feet ... not so much toward "almost" 5 feet.

Or, as Scorpio said in the movie, Dirty Harry, "My, that's a big one!"

Or in Little Red Riding hood... my grandma what a big AC you have. ha, ha.

dadoes, For clarification I saw it on the floor of the distubutor I use. They call it a display model. The size was an estimation. It won't fit in my service vehicle I didn't need a tape measure to figure that out. I know what kind of room I need to replace a bad compressor. I know all these things from doing them not sitting in a forum board nit picking and key board pounding over everything I am thinking about.

Ray,

I think you've got two options: 1.) convince the entire HVAC industry to reverse the trend toward larger outdoor units or 2.) get a bigger truck. Why not pursue these in the order presented?

Thanks Charles,

I know I have more than two options.

Think bigger... but when I say this I am referring to the picture, not the size of the condensing unit.

None of my options include doing what Charles wants.

Ray,

I try to limit your options to binary choices so your brain doesn't explode.

ha, ha, ha.

yet I still won't do what you want, Charles.

sigma vs alpha I suppose?

Nope. The difference is that my grey matter is inside my head.