Time to replace our 1994 system… Seeking feedback on

Greetings HVAC gurus!

Our system from 1994 is starting to accumulate repair costs, also parts are getting hard to find… you get the picture 😩

It’s a 2,700 SqFt house in Michigan; the current furnace is 120,000 btu (which I’m told is oversized) and the AC is 3 ton.

Still in the process of gathering info, but so far I got quotes for system based on:

1. Bryant 100,000 btu 926TB 2-stage furnace + 127 4 ton 16 seer 2-stage AC
2. Lennox 90,000 btu EL296V 2-stage furnace + EL16XC 3 ton 16 seer 2-stage AC

After rebate, these are within $500-600 of each other.

I would appreciate hearing your thoughts and experience about these system.

Thanks in advance!

Why is the Lennox dealer suggesting you go up a ton in size?

Please post the heat and cooling load calculation calculations – or at least their conclusions.

Did the calculations, Manual J or whatever, from all the contractors come out the same?

PHM
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Originally Posted by Zevi

Greetings HVAC gurus!

Our system from 1994 is starting to accumulate repair costs, also parts are getting hard to find… you get the picture

It’s a 2,700 SqFt house in Michigan; the current furnace is 120,000 btu (which I’m told is oversized) and the AC is 3 ton.

Still in the process of gathering info, but so far I got quotes for system based on:

1. Bryant 100,000 btu 926TB 2-stage furnace + 127 4 ton 16 seer 2-stage AC
2. Lennox 90,000 btu EL296V 2-stage furnace + EL16XC 3 ton 16 seer 2-stage AC

After rebate, these are within $500-600 of each other.

I would appreciate hearing your thoughts and experience about these system.

Thanks in advance!

Originally Posted by aa7483

Why is the Lennox dealer suggesting you go up a ton in size?

(you mean the Bryant…) He said that 3 tons is a bit undersized for the house.
Thanks!

Originally Posted by Poodle Head Mikey

Please post the heat and cooling load calculation calculations – or at least their conclusions.

Did the calculations, Manual J or whatever, from all the contractors come out the same?

I don’t have the calculations (one used some special wheel-like calculator, the other his laptop), so I can’t post or comment on whether they were the same.

Thanks!

I’m sorry yes the Bryant. Did you have problems cooling the house before?

Originally Posted by aa7483

Did you have problems cooling the house before?

Yes. Upstairs is always too hot, when it’s upper 80’s outside I could not get the main floor below 75-ish, far-end rooms always suffer (both heat and cooling).

Of course less-than-ideal ducting could be an issue and a longer-running fan in a 2-stage design should make a big difference on its own.

I would start with a proper load calc then and an evaluation of the duct system. Keep in mind a larger system will cool the downstairs sooner and leave the upstairs even hotter.

Originally Posted by aa7483

I would start with a proper load calc then and an evaluation of the duct system. Keep in mind a larger system will cool the downstairs sooner and leave the upstairs even hotter.

As far as load calc, I trust that the professionals did a better job calculating it that whatever I can do, and I agree that ducting could be an issue — but it will bring the project to a much larger scale than I’m ready for (either way, ducting was not something that “jumped” out as a critical problem). Also, with the thermostat located in the center of the upper level (open space), I suspect it may cut the system off too soon in the winter more than in the summer.

You may want to consider that the entire problem may be ducting. That duct system may be inadequate for the 3 tons you have now. When you increase the size of the equipment you’ll be making matters much worse. Don’t be afraid to ask for the data that supports their findings. Easier to find out now that they just don’t know or don’t care than when the system isn’t performing. I hate to say it but we see it far too often.

Originally Posted by aa7483

You may want to consider that the entire problem may be ducting. That duct system may be inadequate for the 3 tons you have now. When you increase the size of the equipment you’ll be making matters much worse. Don’t be afraid to ask for the data that supports their findings. Easier to find out now that they just don’t know or don’t care than when the system isn’t performing. I hate to say it but we see it far too often.

Good points – I will definitely try to find more information. I have a couple more estimates coming in the next days, so I’ll make sure to ask the right questions.

Thank you!

Originally Posted by Zevi

Good points – I will definitely try to find more information. I have a couple more estimates coming in the next days, so I’ll make sure to ask the right questions.
Thank you!

After you GET TO FIRST BASE on the Manuals J and S calculations,
… … you may Logically pursue the RFP phase.

If you don’t have the load calculation in your hand, then ASSUME they haven’t been done! Now they are not done for free, several hours are needed to gather the information and transfer it to the computer. That fee is paid up front and credited when the contract is signed.