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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 You’re not wrong, you’re just advocating the wrong solution. Conditioned attic spaces with insulation under the roof deck is the best approach for slab on grade new construction with high solar loads and AC demands.

@transcendentape But that's the thing, isn't it? A conditioned attic space becomes a conditioned space.

If you want to spend the money to turn it into one, I ain't gonna stop you. But most people just leave their attic an attic for one reason or another. And if that's the route they've chosen, ducts and the air handler should go somewhere else.

Plus, in many of the homes I'm talking about, the attic ain't tall enough to turn into a useful space anyway.

@TechConnectify The point of making an attic include d into the conditioned space isn’t to reduce the relatively minimal AC losses, it’s to deal with the condensation that results when an attic that reaches 150F and 80% humidity reaches an interior space conditioned to 75F or so. Your solution doesn’t address the fundamental problem we deal with in the South where we have night-time temperatures higher than desirable, high humidity, and no basements.

@TechConnectify What is fundamentally different between a wall and a roof? A wall can be shaded from the vast majority of solar thermal load simply by building overhangs. The roof cannot.

@TechConnectify So, instead of continuing the building scheme we’ve used since before there was A/C, it’s better to remove the pressure cooker that is an attic entirely. Is it cheap? No. But in new construction, the price differential is a handful of dollars per square foot and in my area, far superior than any other alternative.

@transcendentape I mean, if you want to remove the attic space, go ahead.

But understand that for homes around here, *NOTHING* goes in the attic. The attic has tons of vents at the eaves and the peaks to keep air flowing through it. Does it get beastly hot up there when the sun shines? Absolutely! But there's a layer of R-50 insulation above the ceiling to battle that intrusion.

And that beats the pants off of any insulated ductwork.

@TechConnectify I mean, go ahead. We live in entirely different climates with entirely different residential construction norms.

@transcendentape my central point is that I think people in different climates could learn a thing or two from us. Our summers can be just as bad as down South, if less consistently. Perhaps that's the only reason our attics don't get moldy, but I'm doubtful.

You pointed to duct losses as minimal, but the first estimate I found puts them at 25-40%. That's a lot of energy being wasted and money being spent to condition space you're not in.

We just... don't do that.

@transcendentape our M.O. has largely been to treat the attic as a space which is there to frame the roof and that's it.

It's functionally outside, so once the sun sets the conditions up there equalize with the outdoors quickly. And sometimes we even use a fan controlled by a thermostat to force some airflow! But that's relatively uncommon.

From my perspective, the reason we don't deal with mold is mostly that there's nothing up there colder than ambient temps.

@TechConnectify “It’s functionally outside”

This gets to the heart of the matter. I don’t think you appropriately appreciate how bad attics are in my climate.

Pre-A/C, homes were built with 10 or 12 foot ceilings and windows to allow cool air in the bottom and warm air out the top. When we got A/C and started insulating walls, we ran into all kinds of problems with mold. Walls can be protected by rooves, but there’s nothing to protect the roof.

@transcendentape Well, to be honest, I'm confused by what you mean by "bad attics." Can you elaborate?

But to circle back to the climates things, when you say "started insulating walls" - this is it right here. We've been doing that *forever* because we have to. And absolutely critical to that is a nice thick blanket of insulation above the ceiling. It doesn't really matter how hot the roof (or attic) gets when you have that barrier in-place.

@TechConnectify As a matter of fact we have not been doing that forever, at least in my climate. This is precisely the confident ignorance that I am upset with you about.

@transcendentape OK... let's rewind, here.

This whole discussion is about regional/climactic norms. It started with my challenging them, and you described what's done in your area as "the best approach"

Really, all I'm trying to do is challenge that, and offer up what's been normal here for a long time as an alternative. Perhaps, if someone ventured to try building a home down there just like we do up here, it would be much more comfortable and take less energy to cool.

But, perhaps not.

@TechConnectify You could test that hypothesis by observing what good homebuilders are building.

Matt Risinger is an Austin,TX homebuilder that deals extensively with these kind of questions, and he has a Youtube channel that covers a lot of the issues we’ve covered.

@transcendentape I'm familiar with those channels, and Risinger specifically! I largely like a lot of what they feature, but there's other things I totally don't.

For instance, I think tankless water heaters are extremely overrated and a barrier to home electrification. And I'm still perplexed by the attic thing - I need to log off soon but I want to repose my thoughts here on last time in a different way:

@transcendentape What does the air handler do? It produces the cool (or warm) air that you need, and it costs you money to use it. Therefore, that air has a raw dollar cost and you probably want to minimize waste.

This is the raw crux of my whole deal. It seems entirely self-evident to me that you should put the machine that costs money to use inside the space you want it to heat and cool. And, you should keep all components of that machine (i.e. ducts) in that space, too.

@TechConnectify I mean, yes. We are arguing the same point. The difference is that in the south, where nighttime temps are frequently above ideal and humidity is an issue, moving the structure of the A/C down to the liveable area doesn’t solve the problem. In fact, it makes it worse. The problem in the South is the existence of unconditioned attic spaces.

I’ve never walked outside to -20F temps.

I have seen a cloud below my ceiling due to dewpoint.

@TechConnectify What you might not be appreciating is the very different response water vapor has between-20f and 80f versus 150f and 80f

@transcendentape Oh no, I appreciate this but... again, in the summer this absolutely something we deal with. And to be honest, I feel like putting a cold thing in the attic is /way worse/ than not doing that.

In fact, why is keeping the AC entirely in the conditioned space worse? I need you to explain that because truly I'm not seeing it.

Our homes just flat out don't have ceiling penetrations into the attic other than an access hatch and electrical boxes. The attic, as I said, is outside.

@TechConnectify “Why is keeping the A/C entirely in the conditioned space worse?” Because in my climate, in conventionally built homes that aren’t built to the standards that we both are advocating for, those losses are necessary to ensure the attic doesn’t become a pressure cooker.

@transcendentape ehh... to be honest I still think there's something we're talking past each other on, here.

In my head, you can take any existing home where you are, get the HVAC out of the attic and run ducts below the ceiling, then patch up all the holes, add the sea of cellulose that's normal up here above the ceiling, and you'd be right where I want you to be.

No mixing at all of conditioned air with attic air, and sufficient ventilation prevents mold.

Am I missing something?

@TechConnectify No, you’re not missing anything except for the fact that very few people look at a 1200 square foot home and think, “How can I reduce the usable size?”

@transcendentape OK, if we're there then, this is all buttoned up.

To be clear, I'm not saying people should sacrifice floor space and get the air handler out of the attic. If they want to maximize both energy efficiency and usable space, I would probably push towards a mini-split setup.

But what I /am/ saying is... next time you build a home, add another 50 sq feet for the air handler closet. That's only been in my head 'til now, but that's where I've been from the start.

@TechConnectify Absolutely no arguments from me… except that if you’re building a new home in my climate, you should consider eliminating the attic as a non-conditioned space, regardless of where your HVAC is.

@transcendentape Agreed. I would, however, be curious to know whether there have been comparisons between a conventional attic with R-50 or maybe even R-75 insulation above the ceiling and a home where the attic has been eliminated or otherwise mildly conditioned.

But at this point, that's just academic!

@TechConnectify It’s not only academic, but entirely unrealistic. The only way you could ever find thise R values is if you paid someone to build your house for you.

I can wave a magic wand as well.

@TechConnectify You’re essentially requiring a second structure to be built around the structure simply to hold the insulation. What in the world do yo propose to use as a regular building material with R50?

@TechConnectify And, more importantly, why?

Solar, wind, and hopefully storage and distribution will catch up soon. Advocating for R50 is not just unrealistic but possibly counter-productive in almost all situations.

@transcendentape Just in case I've misled you, I just mean above the ceiling to the attic. We don't go to that extreme for walls.

This isn't exactly a code reference but this is what we do here

https://insulationinstitute.org/wp-content/uploads/2015/12/IL-2012.pdf

@transcendentape And like, if this surprises you... that's kind of my whole point!

When I said we insulate the living space from the attic, I /meant/ it. Works just as well when it's -10 up there at night as it does on a hot summer day at 150 degrees.

@TechConnectify water vapor is what you I think you aren’t considering, but I accept your point.

@transcendentape Eh, I still feel as though with enough breathing (which, again, we absolutely ensure with roof and soffit vents) it's not a concern. The structure is only cooler than ambient for a few hours in the morning before it starts baking, and then when it's cooling off it's all really hot and water won't condense on it.

Breathing is critical, though, and I'll accept it may not be enough where you live with consistent grossness.

@TechConnectify I feel like we’re now arguing about finer points that I am not at all qualified to argue about.

@transcendentape Honestly, same. But I can attest that mold problems in attics are not at all common here.

It's usually either signs of a roof leak or as I said earlier the home was built when we thought "sure, just blow steamy shower air into the attic, it'll be fiiiine"

@TechConnectify I can attest that you and I are not in the same climate and I don’t understand why you continue to make this point.

When I started this conversation, I said, “You're not wrong, you're just advocating the wrong solution. Conditioned attic spaces with insulation under the roof deck is the best approach for slab on grade new construction with high solar loads and AC demands.” I stand by that claim.

@TechConnectify I’m not particularly interested in arguing the point further, as I doubt both of our qualifications.

@transcendentape So by no means can I assert the same would be true where you live. I don't know the specifics of what causes moisture in attics for you.

Was just giving food for thought