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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.

@transcendentape Without trying to toot my own Midwestern horn too much, that's really what I'm getting at - yes our climates are different, but we had to learn how to keep a home habitable for a reasonable cost when the outside air is at -20°F, and we absolutely have our own moisture considerations at those temps.

Bottom line, though, you're still in a battle with a temperature gradient, and lot of those lessons we learned over the decades translate nicely to cooling.

@TechConnectify Dude, do you not see the difference? I’ve seen -20f exactly zero times. There are are likely 90 days a year nighttime lows don’t drop below 85 for me.

Your arguments simply don’t apply.

@transcendentape ...

OK, look. Heating and cooling are different tasks. Sure. You don't really need much heating.

But just as you're trying to keep hot air from getting in your home, we try to keep it *in* and that's the same thing! You're slowing thermal transfer with insulation. Which is why it also works for cooling.

Really, what I'm getting at is... perhaps the places of the country that have to battle an 80 degree temperature drop might have some lessons for other parts of the country.

@TechConnectify For sure. That’s a condition I almost never face. My general problem for eight months of the year is dealing with heat and humidity. This is related to your problem, but not at all the same.

@transcendentape And there's no disagreement from me! If I just plopped the house I live in where you live it would be wildly overbuilt for your climate.

But... I can pretty much guarantee it would cost a lot less to cool. And I guess what I'm really asking is... why wouldn't you want that?

From this side of the screen, it's like I'm saying "we cannot get away with cutting corners" and you're like "well we can, so we do" and I don't really know how to engage with that, honestly.