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This is a test rant for a future video that may or may not happen.

But seriously, I cannot fathom how HVAC stuff in attics (or crawlspaces!) got normalized. Especially in new construction.

You virtually never see that around here (the most common application is old homes with radiators for heat who want to add central air) and for good reason!

@TechConnectify so, as a former Arizonan, it’s for several reasons:

1. No basements
2. Originally the whole unit was on the roof, so this protects the air handler from the sun much better
3. You typically have the air output registers in the ceiling so the cold air can fall through the room anyway, so why not put the ducts up there too
4. It was un-used space, so why not

@LordOphidian The thing about soffiting and running the ducts below the ceiling was to address both points 1 and 3.

As to point 4 - I feel like making servicing the thing such a pain the ass just to save some floorspace is... well, I wouldn't go that route.

And I've seen some of those rooftop package units out West. Another thing that I cannot fathom, frankly, but whatever.

@TechConnectify the roof top units pre-dated the others as far as I’m aware since they could be put in place using the existing swamp cooler ducting.

Problem is, the units would get worn out by the sun and the controller boards would burn out a lot (at least from my experience as a kid with ours needing repair often).

@TechConnectify Service wise, it’s probably hard on the techs, but access isn’t too bad, since only the air handler is put in the attic and they didn’t seem to do too much to it when checking it. The condenser outside is where they would spend most of the time.

Soffits are… not appealing visually and I only ever saw them for houses where they added ducting or some sort of piping after the house was built.

@LordOphidian All I gotta say is I'd hope you give up a bit of visual perfection to gain a ton of efficiency.

I said this elsewhere but I was just at my brother's house near San Diego. The fact that when the A/C kicks on there's a blast of HOT air at first is infuriating to me.

For the record, soffits are uncommon up here. We generally run ducts through the floors and use central wall voids for return ducting. Seems to work just fine for cooling, tbh, but people disagree.

@TechConnectify central wall voids like between the studs? Seems too narrow, plus there’s fire breaks half way up?

In my houses in Arizona I never took note of a blast of hot air when it came on, but maybe I’m just conditioned to it.

@TechConnectify so, at least in Arizona, it’s been code for a long time to have a 2x4 (or 2x6 if you are lucky and have thick walls) that runs horizontal across the midpoint between the studs so you don’t have airflow up the void. Helps prevent fire from spreading up the wall voids.

Sounds like your duct would have to be less than 3.5” deep, and could only run half way through the wall.

@LordOphidian I'd have to look into specifics of our firebreaks but either there's a carve-out for bays used as a return or else the specifics are different.

Full-disclosure, though, I haven't toured a single-family home newer than ~2010. Code might have changed.

I now live in a townhome which uses the main stairway as the return. The air handler is in the room at the bottom and sucks air in through a large grill. Bedrooms have a vent through the wall to connect to the hall.

@LordOphidian Still, though, the ducts actually distributing conditioned air never venture into the attic because, from everything we've ever known about energy use, /that would be silly/

The attic is for framing the roof and maybe storing some knickknacks if you feel like it.

@TechConnectify I didn’t take many pictures of it in back when we were building the house in 2005, but you can kinda see that they insulate the ducts, so it helps reduce that energy loss.

Also I’m used to attics having blown in insulation outside the platform under the air handler, so you don’t really store anything up there.

@LordOphidian Thanks for the photos.

It's still puzzling to me, though. Like, sure, you can insulate the ducts but if you just keep all that stuff out of the attic... you just don't have to. You don't even have to think about it!

That's pretty much my whole deal. I can't really fathom the "why" beyond it saves a bit of floorspace and/or you prefer a flush ceiling.

Perhaps it's because I've always been energy conscious, but those why's aren't enough for me.

@TechConnectify it saves quite a bit of floor space though, since the air handler is way larger than any closet in the house besides the master walk-in, so you’d have to make a bed room smaller or something to build a special closet for it.

I suppose you could put it somewhere in the garage with the water heater, but why when you want the cool air coming from above you and you have a bunch of unused space up there?

Not, that your wrong about energy use, but it’s not 100% of the design goal.

@LordOphidian Eh. I dunno if I'd say "quite a bit"

Around here, your furnace and water heater are generally best buds. And something no bigger than a typical bedroom closet can easily house both. That's exactly what I've got in my place. Maybe 25 square feet.

And I have the luxury of a washer/dryer closet upstairs! In many homes you'd have a utility room in the core for all that stuff

This is really just an exercise in comparing norms - but I'll still never see equipment in the attic as such!

@LordOphidian Well right, and for context, there's a return grille in /every room/ with our setup. So one or two bays per room feeds down to that trunk line. The filter is then right before the furnace/air handler.

Homes built slab-on-grade usually have a big grill on the side of the closet with the furnace in it. Just like my new place. If they're smart, ducts will stay below the attic level. For two-story homes, lower level will get ceiling registers, upper level floor registers.