Finally! A better way to run HVAC ducts in residential construction

[@JohnDoe-id9hi]

Great video and product! I've been researching ways of adding ductwork to circulate the heat better than fans in my log home. Thank you.

[@SawHorseDesignBuild]

This could work. You would need an HVAC designer to create a duct design before you could order them though.

[@tmiller4244]

Great system if you want to heat your ceilings. Hot air rises - installing heat registers on the walls up near the ceiling would be terribly inefficient to warm anyone standing or sitting or walking near the floors.

[@allisonfriedman8614]

Nice - I might need these to retrofit at least one room of our house. The space at the top of this pitched ceiling was too small, but they ran large ducts anyway (long ago, so maybe smaller wasn't an option, but then maybe some collaboration and communication could have happened and a slightly lower ceiling would have done the trick...), and the large duct is crushed in on itself and that room just runs so cold.

[@SawHorseDesignBuild]

What is nice about this system is that you get multiple ducts per room so the air flow is more evenly spread as well. This helps with comfort.

[@insurancethatfits]

Isn't the rub on small diameter ducts higher internal friction and the corresponding drop in efficiency?

[@NigelWatts]

The short answer is no; when you have enough ducts to make sure the total static pressure in the supply is correctly managed through the design process.

[@kg4lod]

@@NigelWatts It's still incredibly inefficient. Airflow is proportional to the diameter TO THE FOURTH POWER. It's not linear. One 10" duct carries 3 TIMES the airflow of two 5" ducts combined for a given static air pressure.

[@jonesmechanical]

Take one room that needs 250 cfm. A 8" round duct does it with a .10 friction rate. A 3" vent will allow for about 15 cfm at that same friction rate of .10. It's so bad. It's unbelievable. So that room, would need 16 or 17 three inch vents in it all things being equal. The space needed for those 16 or 17 runs would take up more than a single 12" round space. Something that could have been done on a single 8". It's just criminal. So it's not space efficient at all. The most beautiful duct systems you see are in mother nature. Look at how a tree is formed, a river system, our cardiovascular system. We don't have tiny blood vessels home running all the way to our heart. Its pure comedy the lack of doing simple math here.

[@magallanas]

Did this system get installed yet on the retrofit? Any feedback on how it is working?

[@rickzwolinski]

The typical registers are terrible. i like what you are showing

[@M14GARAGE]

Where can I buy this from?

[@ToddBrooks-l4n]

What’s with the headphones

[@jonesmechanical]

The math doesn't work out. This product was sold to national home builders directly, and its gaining popularity extremely fast, and I predict its going to implode as fast as its coming on to the market. Typically, I'm seeing 25-35 3" runs, and there must be lots of 2.5 to 3 ton applications in that range. Most HVAC guys would agree, on the supply side, the equivalent of a 15" or 16" round would deliver that 2.5 to 3 tons depending on how complex, long the supply and return air is, how much static is available after a filter, coil, furnace/Air handler has been designed into the system. The vents themselves are also very restrictive when compared to a typical vent you see available at even home depot (just looking at their shape). I get it, its about creating some velocity at the air exit. But the shape in both the round and thing wall vents is by its nature restrictive, a lot more than a typical 4x10 vent when compared to what the air volume its delivering. The big issue here, is the math, and static pressure, even running out a 16" equivalent trunkline, to 12, final 6" vents, keeping crossectional area constant in comparing 12, 6" vents, with with 12, 6" vents, that nets a 336 sq inches. These small 3" vents, are only 7 sq inches cross section. So, to keep crossectional volume similar, you would need 48 of these small 3" vents. If this company says its ok to have less vents than that, wow, its only going to perform worse, not better. Now, back to 12 vents, 6" size on a normal 3 ton application, 336 sq inches, that has a circumference of 216". That 336 sq inches of air is contacting 216 linear inches of ductwork as it passes through it. Static pressure is directly caused by the air interaction with surfaces. 48 of the small 3" vents, give you the same 336 cross section, except now that air through all 48 of those 3" vents is interacting with 432 linear inches. We are talking about double the surface area that the air has to contact with, its all friction, and thats assuming all things equal, we are comparing 6" home run lines just like these 3" lines are run. With a normal HVAC design, a single 16" trunk would apply here, and that helps even more the static pressure to be lower. As we know, static pressure isn't a linear relationship, nor is a blower curve. I'd love to know what Rheia recommends for a 3 ton setup on a small home, how many runs. I doubt its 48 lines, if its not, and its much less, the issues only compound. This is why so many people think this system is "high velocity" and it isn't. Its only the velocity and static pressure a normal furnace can handle. Max capability on the best variable speed furnaces is .8" static on heating, and 1.0" static available on cooling total. This is so so so so bad. a 3" duct (metal) running 30 cfm, has a friction rate of .28 inwg/100ft. A 6" duct running 100 cfm has a friction rate of .08 inwg/100ft. We are talking 350% higher friction rate. And thats compared to 6" home runs to every vent, which its widely frowned upon, because its one of the most restrictive ways to run a duct system, super inefficient labor wise, ineffective for packaging. This is just doubling down on a terrible installation method of 6" home runs, but in a result that is way worse that double. Closer to 4x worse. Critical thinking is gone. Packaging isn't even a win. Its just a dumbed down way to do hvac that takes the thought out of it to make things simple, but the impact on all things are going to be terrible. I understand, the market we serve is high end. I run about 50 guys, 10 Million a year revenue working on 150 Custon Estate homes a year that are all between values of 3 Million dollars, up to 100+ Million dollars each. But I didn't get to working on these homes over night. I have worked on all types of projects. Having 5 or 6 vents in a room where one would do it. What wall clutter. I'd love to know more. Anyone who has information they can post here, that would be great. For now, until someone can explain the math to be different, this brand Rheia, is missing its first name Dia. Its no different that the Aria vents that are out there. The math doesn't work.

[@SawHorseDesignBuild]

Did you get the answer you were looking for yet? I think I saw this comment on several channels.

[@firemusic82]

This looks awfully familiar to a system we typically call a “flex bomb”. A plenum with an octopus of flex coming off of it.

[@jasonLeno]

Isn't this just a radial design with compact sizing????

[@dustinpetty7352]

It looks like there's no insulation on those ducts. That's kind of scary when we have uninsulated ducts They condensate like crazy. I live in Miami and the humidity is off the chart even in the winter. 90% of the time Our ductwork is in an unconditioned attics. It Seems like this product would only be good for ductwork. That would run a conditioned space.

[@SawHorseDesignBuild]

This system is not designed to be in an unconditioned space. Unfortunately, 90% of the systems are in unconditioned spaces. That amounts to huge energy loss and costs for the end user.

[@vespaman101]

At the beginning he says we don't want these in unconditioned spaces. These ducts will be in the walls within the insulated area of your home.

[@timmytucker6902]

I didn't watch much of the video but reminds me of a unico system.

[@SawHorseDesignBuild]

This is low velocity to work with standard equipment

[@rickzwolinski]

Small ducts means high velocity air system which is horrible. Cant humidify, keeps you up at night. Give me traditional duct work anytime

[@Krunch2020]

Add an ERV system and you have another 10 ducts. Way too many ducts. Better to have a multi split ductless system for HVAC plus ERV.

[@SawHorseDesignBuild]

I used to agree with that. The only issue is you don't have central filtration for the air then. The ERV is designed for exhaust and fresh air but does not filter the circulating air. Most ductless systems don't have great filters for filtering PM2.5.