HVAC help......ughhhh

[Runs With Scissors]

Ok fellas, my AC went out a few days ago.

No big deal since it's fall here, but I do want to/will replace it soon.

Since the system is ~24 years old, I want to replace the furnace too as a 'matched set".

I have decided to take it on myself, but I have a few questions on furnaces.



I already bought a Goodman 3 ton AC unit, A coil with case, a new "line set" and pad.

I want to order a furnace but I'm having some difficulty figuring out which to get.

For "simplicity sake" I would like to replace it with a unit as similar as possible.

SO,

I have an 80% unit that I presume is a "single speed blower". (I think)

Since I have never done this before, I would like to keep things 'simple and reliable".

But all the sites that I look on, they only have "variable speed", or "9 speed" or "multi speed".....Are there are no "single speed" models made anymore?

This are the 2 the units I was looking at.

https://hvacdirect.com/80-000-btu-8...-stage-goodman-gas-furnace-gm9s800804bn1.html

https://hvacdirect.com/80-000-btu-8...s-furnace-upflow-horizontal-gm9s800803bn.html

I don't understand the difference between "9 speed" and "multi speed" ?

 

[Bmyers]

I think I can help with the 9 speed verses variable speed.

Differences:

• Cost, 9 speed usually cheaper on purchase
• Operation, variable speed is cheaper in operation cost (more efficient)

Both will work, it just depends on what your priority is, lower cost up front or more efficient and cheaper operation.

Add additional,

I should of read just a little closer case you stated 9-speed vs multispeed. The 9-speed is just like it states it has 9 speeds the blower can run at. Multi speeds are just that multiple speeds, usually a high, medium, low type speed.

The variable speed is generally the most efficient because it has a wider ranger of speeds.

(I asked one of HVAC techs for the Cliff notes version, he was going into way more details than I was willing to type.)

 

[PoTreeBoy]

With the multi-speed there is a terminal strip so you plug the wire corresponding to the speed you want. You probably use two speeds, a higher speed for cool and a slower speed for heat. Maybe another one for fan only.

 

[Tughill Tom]

I'd look at a higher efficiently unit, 96% to 98%, direct vent fully condensing. Most come with a variable/VFD motors to improve overall performance. it will pay for itself in fuel savings.
Also look at the heat exchanger material and the warranty on them, the better the more $$.

 

[RCW]

I don’t want to take a tangent from @Runs With Scissors thread, but neeto pose a question as I think it’s relevant.

I was posed with HVAC concerns related to recent house projects.

I considered mini-splits to get both heat and AC.

Don’t really know anything about them, but know they are a common replacement in some places.

Didn’t do that as cost prohibitive but seemed they’re better than just a few years ago? Heating systems now effective at -10 or -20F?

I know @Runs With Scissors is in Michigan, so I believe even colder winter temperatures than we have in upstate New York.

Are one of those mini-split systems even viable in a cold climate?

I know several folks that have put them in As their sole HVAC solution. Just not sure I’m prepared to sign on for the option.

 

[jimh406]

I would ask HVACDirect or Goodman.

 

[Runs With Scissors]

OK, so I called "HAVAC direct" and the guy told me that Goodman uses 2 names "9 speed" and "multi speed', but they mean the same thing.

Apparently he was correct too......I hate just taking someones "word for it" so after some searching I found this 'decoding chart' and the difference between the 2 models I listed is a (3 and 4) which is the "tons"

GM9S800804BN VS. GM9S800803BN

The 9 in both of the part numbers means "9 speed"

So decoding the above part numbers mean that these are both

Goodman
Upflow
9 speed
1 stage
80%
80,000 btu
One is a 3 ton, the other a 4 ton
17.5 inch wide
> 40 NG/J NOx

units

 

[Runs With Scissors]

So I guess I have no choice really, but I have to get a "variable speed" motor.


If anyone knows that I have misunderstood anything, please speak up.

I would like to order it soon.

Here are some pics for reference.

and right here is one of many reasons to have a tractor!!!!!!


looks heavy!!!!!

nope not heavy at all when you have one of these....

all tucked in and ready to mate up with a furnace.

 

[tbk5]

Goodman ???
Would you buy a TYM or RK tractor?

Yes with HVAC because many brands use the same parts. Today's iteration of all brands will die in 10-12 years. At least that is what our HVAC guy tells us. He's a straight shooter.

 

[Runs With Scissors]

Goodman ???
Would you buy a TYM or RK tractor?

My unit “identifies “ as an Amana…..

 

[Runs With Scissors]

I'd look at a higher efficiently unit, 96% to 98%, direct vent fully condensing. Most come with a variable/VFD motors to improve overall performance. it will pay for itself in fuel savings.
Also look at the heat exchanger material and the warranty on them, the better the more $$.

I am “barking” at the Old Lady day and night about moving.

edit

#1 priority is ……easy install
#2 priority is ……..easy install.
#3 to #1343 is ….easy install

# 1344 is upfront cost….


#1,345 priority is……long term efficiency costs.

 

[lynnmor]

My unit “identifies “ as an Amana…..

When I bought a heat pump the dealer asked me if I want the Goodman or the Amana nameplate. Ask about warranty, depending on what the unit identifies as the warranty may be different. He handed me the Amana plate and threw in a high efficiency decal which really helped reduce energy cost.

 

[Henro]

I got a bit confused about the pictures posted above which seems to be for reference only but looks like they were showing the receipt of the furnace by somebody…

Anyway I installed a new Goodman furnace here in my place which is a different situation than normal and probably doesn’t relate, but anyway I chose a 80,000 BTU high-efficiency model, which I think is 96% efficient. Really satisfied with the unit. Initially I was going to install AC as well, but concluded for my situation it would be better to install the furnace first, and for the purpose of AC if we really needed it to install an air handler and a separate condenser outside and so on and so forth.

So anyway, installing a furnace is not that of a big deal, especially if you’re just replacing something that already exists. In my case it was new installation because I was using something different for heating over the last 30 years. OK, what I was using was two gas wall furnaces that were direct vent and kind of noisy but they served the purpose. The new furnace is replacing those two older furnaces that were 80%, and it’s more than satisfactory and was the right move on my part.

I think Goodman and maybe Amana share the same hardware. I could be wrong about that but I know Goodman and some other manufacturers name are the same.

I put a goodman in the house next-door and it has operated flawlessly for 10 years now. So don’t get too wrapped up in the negative comments about the Goodman Brand. A guy I used to work with who was in the HVAC side at the company told me with respect to a furnace choice, do you want a Chevy or a Cadillac? They both get you where you’re going…

 

[TheOldHokie]

I got a bit confused about the pictures posted above which seems to be for reference only but looks like they were showing the receipt of the furnace by somebody…

Anyway I installed a new Goodman furnace here in my place which is a different situation than normal and probably doesn’t relate, but anyway I chose a 80,000 BTU high-efficiency model, which I think is 96% efficient. Really satisfied with the unit. Initially I was going to install AC as well, but concluded for my situation it would be better to install the furnace first, and for the purpose of AC if we really needed it to install an air handler and a separate condenser outside and so on and so forth.

So anyway, installing a furnace is not that of a big deal, especially if you’re just replacing something that already exists. In my case it was new installation because I was using something different for heating over the last 30 years. OK, what I was using was two gas wall furnaces that were direct vent and kind of noisy but they served the purpose. The new furnace is replacing those two older furnaces that were 80%, and it’s more than satisfactory and was the right move on my part.

I think Goodman and maybe Amana share the same hardware. I could be wrong about that but I know Goodman and some other manufacturers name are the same.

I put a goodman in the house next-door and it has operated flawlessly for 10 years now. So don’t get too wrapped up in the negative comments about the Goodman Brand. A guy I used to work with who was in the HVAC side at the company told me with respect to a furnace choice, do you want a Chevy or a Cadillac? They both get you where you’re going…

I thought everything sold today used outside air for combustion...

Dan

 

[Henro]

I thought everything sold today used outside air for combustion...

Dan

Nope. 80% efficiency units seem to be common. Not something I would buy, but to each his own.

I don’t believe the 80% units draw air from the outside…not an expert by any means though…just going by what I think I remember from reading the specs. I think they are designed to exhaust gasses through an existing chimney.

Some of the high efficiency units don’t require outside air for combustion, but do require exhaust to be vented outside. Seems crazy to take that approach from my perspective.

 

[TheOldHokie]

Nope. 80% efficiency units seem to be common. Not something I would buy, but to each his own.

I don’t believe the 80% units draw air from the outside…not an expert by any means though…just going by what I think I remember from reading the specs. I think they are designed to exhaust gasses through an existing chimney.

Some of the high efficiency units don’t require outside air for combustion, but do require exhaust to be vented outside. Seems crazy to take that approach from my perspective.

I replaced my original Lennox "Pulse" gas furnace a few years ago. It was 30 years old but 90% and had a PVC combustion air intake and PVC flue that come out just above the foundation wall. New furnace is 85% with 2 stage heat exchanger and reuses the same horizontal PVC venting. Flue gas is barely warm to the touch.

Dan

 

[DustyRusty]

I replaced an American Standard condenser and a Goodman evaporator coil this past spring, and I got 7 years out of it. It cost me $7000 or $1000 a year. The condenser leaked, and the coil also had a leak. Thought I was OK until late August and the same thing happened to the other unit. In this case, it was just the coil that was defective, but as the tech said, replace the condenser since it is the same age as the last one, and if it goes bad next year, it is going to be much more expensive. Seems that the refrigerant that the units use is being discontinued at the end of 2024, and no replacement parts can be sold for the older units. The reason that the coils leak is because the pan that they sit in doesn't fully drain and the condensate attacks the metal. The new units come with a new pan, but they haven't fixed the problem. The tech told me that had I had the units cleaned every year, the problem wouldn't have existed. When the new unit gets installed, he is going to put a tee into the drain line so the line can be cleared with a round brush in the future.
The unit at my wife's store was just replaced. It was 41 years old, and the case looked like it had been in a war, but it still was working, but extremely ineficiently.

 

[The Evil Twin]

Stick to 80% unless you want to run PVC out the side of your house. If it's not a finished basement, easy enough.
Stay clear of ECM blower motors. They are expensive WHEN you have to replace it, and often need replacing. They are also a pain because of the extra wiring in the way. After the first time, you will know what to do for the next two times.
Depending on your cost of gas, I would consider a Heat Pump/ furnace combo. Newer heat pumps can be very effective in the single digits. Well, some can. I have installed this combo system in our last two homes. The heat pump runs as long as the outdoor air is above 25° (its not a low temp unit). Below that, the furnace does. Saved 20% in energy costs per year.
Don't get hung up on name. Most of them use the same compressors and an motors. Trane is one of the few that mufature their own. I think Daikin might on higher end models. My last Goodman ran for 13 years without issue. Then I had to replace the condenser fan motor. Still running strong when we left after 15 years.

 

[North Idaho Wolfman]

My heating is 199,000 BTU at 95% efficiency.

 

[GreensvilleJay]

I have 2 Goodman units(house and garage) ,both are 80K BTU and 93% eff, so both have 2" PVC out the wall.
Sad thing is my old house furnace was still 95% eff ,after 35 years so I actually LOST of efficiency.