I Need New Furnace--Carrier, Lennox, or Trane?

[Walt34]

The other companies just did a wag based on the current system.

I'd think that is not always a bad method IF the current system works well for you. We've been here for almost 20 years and the furnace that came with the house works just fine, not too big and not too small. So when the time comes to buy a new one I'd be happy simply buying one with the same BTU output.

Of course if there are issues like some rooms too hot or too cold, or not heating enough during colder-than-normal weather then naturally you want to do some recalculation.

 

[foxcreek9]

An independent HVAC serviceman warned my away from Lennox because Lennox will slow walk the parts to independents. So, if you have a falling out with your local Lennox dealer, it may take longer to repair. We got the Trane.

 

[Happyras]

My experience is that most installers oversize furnaces and some even oversize heat pumps. This leads to high cycling of the system and earlier component failure due to inrush start up current etc. You want heat pumps to run continuously rather than cycle on and off.

On a Furance, most will set the CFM appropriately to maintain proper heat rise in each duct. I like the variable speed blowers which maintain constant flow, rather than a set speed on the fan. Current is proportional to CFM, and those motors drive to constant current. Setting only the fan speed tap, the flow can be limited due to closure of vents and the HX could experience too low a flow, which is also not good. A variable blower motor will increase speed as needed to maintain constant flow across the HX.

 

[eytonxav]

If I was looking to replace mine, I would opt for American Standard or Trane.

 

[OldShooter]

... I look for the primary heat exchanger as well as the secondary hx to be made of duplex stainless steel. ...

Not sure what "duplex" is but when I next have to replace a furnace my first criterion will be a stainless heat exchanger. We have a Bryant whose heat exchanger rusted and clogged after about five years. They replaced it for "free" but the installation was a few hundred bucks and the replacement was, of course, not stainless. We are also on our third (warranteed) induced draft motor as bearings have failed to the point of being very noisy and hence near end of life.

I'll never buy Bryant again. The tech from the HVAC company I used said they no longer install them. They installed Bryant in the boss's house and the boss's son's house back when they didn't realize they had reliability problems. So they thought they were doing well by us when they sold us one -- I am not mad at them.

 

[Happyras]

I love a good materials question;
Duplex stainless steels[1][2][3][4][5] are a family of stainless steels. These are called duplex (or austenitic-ferritic) grades because their metallurgical structure consists of two phases, austenite (face-centered cubic lattice) and ferrite (body centered cubic lattice) in roughly equal proportions. They are designed to provide better corrosion resistance, particularly chloride stress corrosion and chloride pitting corrosion, and higher strength than standard austenitic stainless steels such as Type 304 or 316.

A 2205 SS is one type, or even a lower grade 2102 duplex is best for combustion gas corrosion. These type of alloy stainless is found in quality HX for furnace application. If you ask the installing tech, he will likely not know the difference. This is primarily needed in the secondary HX that sees the condensing gases. The hotter primary HX can even be aluminized steel, since it does not have the same type of corrosive exposure due to temperatures that maintain H2O in vapor, but still an issue.

 

[Qs Laptop]

How many BTU's?

80,000 BTU

The difference in cost between a single and 2 stage furnace is not $700. Do you need a 2 stage?

I'm in Minnesota. My home is a 2-story walk-out. I have 3,000 sq. ft. finished. I want a quieter furnace. I think I'm a candidate for a two stage. What's your opinion?

Do you have an Ecobee or similar stat to control it, or would you rely on its own algorithm to increase on demand?

Currently have an 25 year old Honeywell programmable. I would likely get a new smart thermostat and let it run the furnace.

Consider this;
An 80% efficient furnace would cost considerably less, but require a hot vent stack if you do not have one.

Not sure what a hot vent stack is but currently my furnace vents via PVC piping out the side of the house.

I doubt very much a 2 stage will last any longer. Are they quoting multispeed or variable speed?

I wondered about the longevity argument. It's a two-stage variable speed furnace.

If you followed my link to iwae.com you would get a better feel for real costs. I can replace an 80K BTU gas furnace by myself in about 6 hours, so most of these guys are collecting big time on selling you a new furnace. BTW, you can order a new secondary HX for your Lennox for about $1200 plus install. Not as fast a job as pulling the whole furnace, but figure another $800 in labor and done.

Well, I can't do the install so I'm at the mercy of local contractors.

 

[Qs Laptop]

I'd think that is not always a bad method IF the current system works well for you. We've been here for almost 20 years and the furnace that came with the house works just fine, not too big and not too small. So when the time comes to buy a new one I'd be happy simply buying one with the same BTU output.

When I sourced my furnace and AC 20 years ago the company did the extensive J calculation on my house.

I specifically asked the tech about this today and he said the general rule of thumb for high efficiency furnaces is take the number of square feet and multiply by 30 to get the recommended BTU. In my case, with 3,000 square feet I would need a 90,000 BTU furnace. Since furnaces are typically 80K or 100K BTU he said my house would take an 80K BTU furnace (which it currently has.)

He said that they used to do the J-calculations but time and time again, for most houses, they were within 5% of the general rule of thumb calculations so unless the house has soaring ceilings and/or a lot of windows they don't do J-calcs anymore.

 

[Qs Laptop]

Not sure what "duplex" is but when I next have to replace a furnace my first criterion will be a stainless heat exchanger. We have a Bryant whose heat exchanger rusted and clogged after about five years.

Exactly what happened with my Carrier furnace, a rusted and clogged secondary heat exchanger. Mine took 20 years to get there, not 5, but still. The new Carrier furnace's primary heat exchanger is still stamped sheet metal but the secondary one is of a different design, and has aluminized fins on stainless steel tubing.

Both of the Trane's heat exchangers are stainless steel.

The Lennox has a "Duralok Plus" primary heat exchanger made of "Armor-Tuf" steel, which Google tells me is aluminized steel. (WTH is that?!) The Lennox secondary heat exchanger is aluminum fins on stainless steel tubing.

 

[Marita40]

OP if you are in the Twin Cities I can recommend several good installers. PM me for them.

 

[rk911]

I've heard this as well. But how do you know the particular installers that come to your house on any given day are good or not so good? It's a crapshoot, isn't it?

that's why warranties were invented. stop worrying.

-reputable company with long track record of beiing in business
-compate total price quotes from at least 3 companies
-compare warranties.

good luck.

 

[Happyras]

80,000 BTU



I'm in Minnesota. My home is a 2-story walk-out. I have 3,000 sq. ft. finished. I want a quieter furnace. I think I'm a candidate for a two stage. What's your opinion?



Currently have an 25 year old Honeywell programmable. I would likely get a new smart thermostat and let it run the furnace.



Not sure what a hot vent stack is but currently my furnace vents via PVC piping out the side of the house.

First, a two stage will have a 2 speed inducer fan, and variable speed blower. this may be quieter if it runs longer on lower speed/burners. Properly sized air flow/velocity will run quieter even if its a single stage. Not sure if it would be worth it unless you had a larger BTU model that would need to run on low stage for longer. It sounds like in your climate an 80K BTU furnace is the minimum for a fully sealed 3000 sqft home (off the top of my head thinking). You need to calculate the CFM required and set your blower CFM on a variable unit. Allow 130 CFM per vent register. I suspect you have some shut off and the noise is due to high flow in the ducts? 15 -4x10 vents would be 1950 cfm at the blower, which is about what a 80K BTU furnace will run at with gas and duct temp at 110F+

A two stage variable 80K 21 inch cabinet upflow furnace should cost <$2000 plus install. I would not add any coil to the furnace, install one if you must separately for AC. I would definitely shop this down in your area or buy one after getting install only bids. Some guys like to pick up side jobs on weekends, and for this replacement job, I bet you could get qualified labor through Angies List or Craigs List with caution to check references.

Hot vent is a term for a metal double wall chimney vent. Lower efficiency furnaces have hot exhaust. If you only have a PVC vent, then min efficiency 92% would be best, but then you get the condensate issue.

Buy an Ecobee thermostat, super easy to install and config. About $150 at HD or Costco etc. Set up for a two stage furnace is driven by the wiring and easy programming. Hopefully you have extra wires at the stat to configure the second stage and AC wiring.

A lot of mumbo jumbo in specifying the HX. Get real material specs, or tell them to shove off. Like I said, a lot of mfg offer the primary HX in aluminized steel, which is basically a coated mild steel, nothing to do with alloy or stainless materials. When they say aluminum fin over SS tube, ask what SS. If it is simple austenitic 304, it ain't going to last, like I say, a min would be 316 or better some grade of duplex SS. If its welded I would want specific details, most are not due to high temp stress corrosion cracking in the weld zones.

For the outrageous price you are being quoted, I would want better detail than some made up super steel name.

 

[Happyras]

An example on SS materials;
Weber makes Gas Grills and uses 316 SS, mine lasted 15 years until it was damaged by something falling on it. It did not rust out. Chinese grills (you know the cheaper ones) are made from low cost low alloy stainless, at best 304 ss, mostly worse. They rust out in about 3 to 5 years with use. Gas has corrosive biproducts. YGWYPF.....

 

[badatmath]

My Trane a/c has had one repair. Furnace zero. Installed 1998.

 

[Romer]

I am having a new HVAC system put in Wednesday

I read it was more about the installer than the furnace brand. So I looked up 3 companies with the best reviews in my area and got 3 quotes for the straight furnace AC, and Furnace Heat Pump (Dual Fuel) setups

I was amazed the wide difference in price between essentially the same system among the 3 contractors. All with high install ratings. Two of them didn't respond to my questions well or take the time to understand my existing duct and system setup as it stands now

I ended up going with a Daikin 96% furnace and Daikin 17 SEER Heat Pump (Dual Fuel). It also had the best warranty of 12 years with full coverage by the installing contractor

They are replacing an 18 year old Goodman 80% furnace and 10 SEER AC unit

 

[wolf]

I might add that I have owned/repaired several Lennox furnaces, and installed many Goodman heat pumps and gas furnaces to replace them over the years. All of the Goodman furnaces I have installed are still in good shape. Mostly issues with flame sensors, easy to clean, or broken ignitors but that happens on all brands. A high efficiency furnace has the pain of being a condensing furnace which ultimately leads to secondary HX fouling, or worse corrosion. Makes me want to reconsider and go back to 80% efficiency to avoid all that maintenance.

OP. Read "efficiency" comment. When I had my Furnace replaced many years ago. Here in California. Installer/owner. Said, I don't need a high efficiency
Furnace. He said they cost more, and ARE MORE EXPENSIVE TO MAINTAIN AND REPAIR.

He recommended a Furnace that was a little less efficient. Cheaper and you avoid the issues previous poster mentioned.

 

[Happyras]

I am having a new HVAC system put in Wednesday

I read it was more about the installer than the furnace brand. So I looked up 3 companies with the best reviews in my area and got 3 quotes for the straight furnace AC, and Furnace Heat Pump (Dual Fuel) setups

I was amazed the wide difference in price between essentially the same system among the 3 contractors. All with high install ratings. Two of them didn't respond to my questions well or take the time to understand my existing duct and system setup as it stands now

I ended up going with a Daikin 96% furnace and Daikin 17 SEER Heat Pump (Dual Fuel). It also had the best warranty of 12 years with full coverage by the installing contractor

They are replacing an 18 year old Goodman 80% furnace and 10 SEER AC unit

Daikin is Goodman/Amana, the 17 SEER pump is good, has adequate control protection as well as a suction accumulator missing on some brands. Good choice, the 96% furnace depends on what flavor but should be fine in a dual fuel. i suggest using an Ecobee for the dual fuel control, but they will likely upsell you.

 

[old medic]

I think having a quality installation makes as much effect on reliability as the brand. A bad installation will create problems. Choose your installer first.
I have Goodman heat pump and A/C with propane backup at my house. Have good results now going on 6 years, as a data point.

I will be the installer, but sometimes I have a fool for a client...

That by far is the best statement. A bad install is typically associated with Goodman and Goodman gets the blame.

After doing a lot of research, I'm planning on going with Goodman if we decide to go with a central system over mini splits

 

[CincyDave]

When we had our furnace replaced, I asked the salesman, what he would put in his own house if he were replacing it. He recommended Armstrong as being the best bang for the buck. Had just put one in his daughters house. This HVAC company has been around a long time, and well respected. I went with his recommendation. Did not go with high efficiency. No problems at all so far. This was probably about 10 years ago. Haven't seen that brand mentioned, so thought I'd throw it out.

 

[eytonxav]

When we bought our current home new, it came with two 15 seer Amana (Goodman) systems. Both indoor coils leaked after about 7 years, and while the parts were covered under warranty, there was labor cost involved to replace. I was quite surprised that these coils didn't even make 10 years which is where we are now, although the outside compressors/coils are still working without issue.

 

[Midpack]

When we had our furnace replaced, I asked the salesman, what he would put in his own house if he were replacing it. He recommended Armstrong as being the best bang for the buck. Had just put one in his daughters house. This HVAC company has been around a long time, and well respected. I went with his recommendation. Did not go with high efficiency. No problems at all so far. This was probably about 10 years ago. Haven't seen that brand mentioned, so thought I'd throw it out.

I usually ask that question, but only after the installer makes an initial recommendation. Usually they give a budget and a better option IME, and if you ask 'what would you put in your house' they always seem to choose the "better" more expensive unit. And I don't doubt they would. Most installers have to offer something for homeowners who just want cheap (lots of them), which is usually not the "best" choice IME. I am looking for longevity, reliability and lifetime cost for household systems, not cheapest initially. When I buy big ticket items, I often choose the second most expensive model just below the flagship product. YMMV

 

[REWahoo]

FWIW, Consumer Reports survey results on central A/C reliability and customer satisfaction:

 

[Qs Laptop]

FWIW, Consumer Reports survey results on central A/C reliability and customer satisfaction:

Very nice info to have.

I decided to go with the Trane system, mostly based on the fact that they have stainless steel heat exchangers on both the primary and secondary heat exchangers.

Also their warranty is 10 years on components with 5 years on labor. So I'm completely covered for the first 5 years and then covered on parts for 10 years.

Seeing Trane topping both the reliability ratings and owner satisfaction reports is comforting.

The new furnace is being installed now.

 

[Qs Laptop]

OP. Read "efficiency" comment. When I had my Furnace replaced many years ago. Here in California. Installer/owner. Said, I don't need a high efficiency
Furnace. He said they cost more, and ARE MORE EXPENSIVE TO MAINTAIN AND REPAIR.

He recommended a Furnace that was a little less efficient. Cheaper and you avoid the issues previous poster mentioned.

The furnace I'm replacing is a high-efficiency furnace. I have the forced air exhaust system that blows through PVC pipe, exits out the side of the house. I couldn't go back to a "normal" efficiency (80% efficiency) furnace without the need to re-install a chimney/flue system through the roof of my house, so a high efficiency furnace is my only real option.

 

[Stormy Kromer]

I'm a big believer in situations like this you buy service first, product second.

All new furnaces are good when they work, and they all break sometime.

I replaced my furnace/AC in 2020. I went to my local dealer and asked him "what would you put in your house ?" I fully expected him to say a Lennox, since that has been his main brand for over 20 years. He told me he put a Ruud in his house and that's what he's recommending now.

His reason was parts availability. He said that a Lennox whare house had a major fire and they hadn't recovered yet and parts were hard to come by. Keep in mind this was the summer of 2020, things may have changed by now.

We've had the Ruud for 2 years with no problems.