Downflow furnace 2 story house.

[Chris4u13]

Had a friend of mine complain his upstairs is always uncomfortable in the hot seasons. Saw his configuration and he has ducts in the crawl space for the first floor and then apparently a big supply line coming from the crawl space up to the second floor. This line is located right next to the unit and looks to be cemented in place. So is this a hack job or was this once practical?

Thanks

[DavidDeBord]

Chris,

You're gonna need to post a lot more Data, than what is in your O.P.

What size is "Big"? Is there a R.A. Trunk to the 2nd Fl.? What is the Heat Loss/ Heat Gain for the home? What Equipment is being Used, as well as Brand/ Md.#, & Serial #? Etc., etc., etc.

To save $$$$, would you be wiling to allow Your Friend to stay with you during the "hot seasons"?

Lol! I'm kidding, but,.... More Data is needed.

[Bglenn525]

Id be willing to bet that there is no return air duct going to the second floor, or if there is it’s undersized

[Robber]

Hack job / common practice? Now a days on new installs they are pretty much one in the same.
Yes I see installs with a single duct that runs to the second floor usually to attic then flex duct to the rooms. I would call that a hack job, but others call that normal insulation. The downflows with the duct to second floor I see are townhouses, usually on a slab.

[BaldLoonie]

Around here MANY 2 story homes either have furnace in basement or downflow on the first floor. 30 years ago there would be 1 big trunkline and both floors would come off it. 2nd floor registers would go up an inside wall in wallstack then 6" round out to the register under the window.

Lately they run a single duct to upstairs, maybe a 12" or 14" round then spider in the attic to ceiling registers.

Either way the upstairs is hot in the summer.

[Robber]

Around here MANY 2 story homes either have furnace in basement or downflow on the first floor. 30 years ago there would be 1 big trunkline and both floors would come off it. 2nd floor registers would go up an inside wall in wallstack then 6" round out to the register under the window.

Lately they run a single duct to upstairs, maybe a 12" or 14" round then spider in the attic to ceiling registers.

Either way the upstairs is hot in the summer.

For you yougens wallstack is rectangle duct up the wall cavities. Usually 2 1/4 x 12 or 3 1/4 x 10.

Yep that is the way I did it. Damper in every supply, made the trunk and plenums ourselves. Also the RA used the Joice spaces, and we made "U ducts" for where the RA ran into duct {there were no cutting holes into the top of the ra duct}
You know they worked well too. Think the current generation need to know you need duct/ pipe volume to get proper air flow.

[theoldscroll]

He never will be happy. Trying to push cool to the second floor is difficult when at the same time heat is rising. Hard to fight the physics of air stratafication. Now throw in the fact that people desire a cooler house (bedroom to sleep) than they used to. Bet they're happy with the heat. This is why the minisplit market is a boom now. "Can you live with it if I can make just your bedroom as cool as you want?"

[DavidDeBord]

I've actually had many a home, where Cooling/ Heating the Second Floor Problems were overcome, when the H.O. allowed me to run the proper duct-work.

[theoldscroll]

I've actually had many a home, where Cooling/ Heating the Second Floor Problems were overcome, when the H.O. allowed me to run the proper duct-work.

If we could only convince every builder to allow a 4' x 4' chase from basement to second floor attic, in the very middle of the house. This would solve some issues.

[DavidDeBord]

Oldscroll, I've gotten Builders (New Work),& Home-owners (Remodel or Improvement to the HVAC), to five me "Chases" at several different locations if needed. After I did all of my Calculations, & then took them to the Builder, or H.O.,& also guaranteed that there would be no greater/ no less, than a 3 degree variation throughout the building, most of them were glad to do it. I've used Closets, corners of rooms, & even a couple of times, had a Supply & Return trunk to the Second Floor, on the same wall, & the H.O. boxed those in, & made a Fake Fireplace.
I've also insisted upon powered vents for the Attack, Insulation improvements, & more, And, when this was refused, I'd add that refusal in to the contract. so as to protect myself at a later date, if they chose to complain.