How Aeroseal Seals Duct Leaks from the Inside to Stop HVAC Energy Waste with Dr. Mark Modera | Part 1
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Welcome back guys. So we've got a product inventor on the show today. Have you guys heard of AeroSeal? Well, AeroSeal, if you haven't, is a product that gets blown into a duct and it seals the duct from the inside. It goes to all of the crevices and cracks and stuff like that, that's in the duct and starts to seal it up. Now we are talking to, on this podcast episode, this is a two-part series, we're talking to Dr. Mark Madera.

He's the inventor of the product. He talks us through basically how he came to the idea of this and what AeroSeal is and how it works. This is part one. Part two, we'll get to that in a few days. This is the HVAC Know It All podcast. I'm your host, Gary.

Gary McCready. As an HVAC contractor, we need to be insured, and it makes a lot of sense to have the same insurance company look after all our needs. Lambert Insurance Services has been protecting HVAC contractors since 2009. From general liability to workers' comp, bonding, commercial auto, and more, they've got you covered. Call Lambert Insurance Services for a free quote at 801-937-7030. Welcome to the HVAC Know It All Podcast.

recorded from a basement somewhere in Toronto, Canada. Your host and HVAC tech, Gary McCready, will take you on a deep dive into the industry, discussing all things HVAC, from storytelling to technical discussion. Enjoy the show.

Mark, so AeroSeal is something that I've had a customer use it for a specific use and it seemed to help him. Now I'll tell you how we used it and we can talk about this technology from your perspective and building science and all that kind of stuff. But it was about a year and a half ago, he bought an old home, a century home in an older part of a town. And he had a lot of

air infiltration, air leakage. And he had somebody come in and use aerosol to go and fill all the gaps around the home and stuff like that. And he brought his air changes down from 14 or something like that to about four by using the product. So he was using, he was not sealing the duct system. He was sealing the... It wasn't the duct. He was sealing the envelope with it. Yeah. Okay. Okay.

They call that AeroBarrier, but that's fine. Oh, is that AeroBarrier? Okay, but is the product similar then? Yes, it's a very similar product. Okay, I could have sworn he told me it was called AeroSeal. But anyway, if I'm wrong on that, I will put my foot in my mouth and chew on it. I'm okay with that. It's a 10-point thing.

Don't worry about it. They're always changing. You could have been called Aerosil Envelope, Aerosil Duck. They did that for a little while. I'm not sure what would have been in place at that time. But at any rate, he's sealing the envelope of the building. Was the building occupied? No, not when they did it.

Okay, that makes sense then. He had... Occupied meaning a furniture and all that inside the building? Oh, no, no, no. This was under construction. It was under renovation at the time. Because our applications, we've done a home that is occupied, not occupied meaning like furnished. And in that case, you do it a different way. You wind up, you depressurize the house and you put the fog in the attic and it sucks it in that way. But if it's a major renovation, what I'm sure they did is...

is they just fogged the inside of the house and pressurized it. Okay. Yeah. I believe that's how they did it. They had a blower door from what you told me. And basically they used the blower door to pressurize the home and release the arrow barrier, if that's what it was. They released the sealant inside the house.

and pressurized it, it goes not to the leaks, binds them and seals them. Correct. Okay, so let's talk about the aero seal then for the duct because that is sort of the conversation that I wanted to have with you because duct leakage is a big thing, especially if it's leaking inside walls and ceilings and stuff that you can't get to easily. If it's under floors, stuff like that. I was at a home two years ago and the lady was complaining that her heating bill was extremely high.

And her home was maybe less than a thousand square feet or somewhere around that size. And what was happening is that under the floor where her ducks ran, it was not capsulated. So it was cold down there in the wintertime relative to the space. Was it a crawl space or a basement? It was a crawl space. It was a crawl space. Okay.

Okay. So, walk forward to the crawl space. Yeah. So, if you pick up the floor panel to look down, there was all kinds of... You could even feel the duck leakage in the partitions of the duck where the duck was...

um, position together, like with the cleat, with S cleat and drive cleat, you could feel it with your hand. So I, I said to her, I said, the, the AeroSeal could be a product to help you out, but you're also going to have to do something with this crawl space because your duct is not insulated and you're losing all the heat, uh, from your duct. Right.

to the crawl space. So by the time it gets to your home, you've lost air pressure in your duct because you're losing it inside the crawl space and you've lost heat because your duct's not insulated and your crawl space is not encapsulated. So anyway, I just wanted to bring that up as sort of a precursor to the conversation. Well, one comment about that is interestingly, if it's sheet metal ductwork, which it sounds like that's what you're describing as the most inflexible.

That means it's uninsulated. And so the biggest selling point for a bunch of our dealers in the Chicago market is they were not even selling energy savings. They were selling comfort.

Because the other thing that happens is sheet metal ductwork leaks a lot more than flex duct. And so what happens is you lose enough of the air that each slug of air going through the duct system spends a longer time in the duct, right? The velocity is lower. If you leak 25% of the air, the velocity is lower. The air spends longer in the duct. So not only would less air make it into the house,

but it would be colder in the winter and warmer in the summer. Correct. Because what happens is it goes through too slowly and it sucks up all the heat in the summer or loses all its heat in the winter because it spends forever in the duct. So actually what we would do

is we measure the temperature coming out of the ducts before we sealed it, and then we'd seal it, and then you'd measure the temperature afterwards. And not only did you get more air, but the air was warmer in the winter and colder in the summer. Okay, so does aeroseal also insulate the interior of the duct? It does not insulate. It does not insulate. But what it does, if you think of the duct system as a heat exchanger, the slower you go through the heat exchanger, the more efficient it is.

And you don't want an efficient heat exchanger with the outside. Right. That's a bad thing. Right. So by speeding, by speeding up the airflow through the duct because of sealing the leaks, it's a less efficient heat exchanger with the outside. So without adding insulation, the temperature will actually improve. Okay, cool. So it doesn't add insulation. It just makes it that the air spends less time. Yeah, it just, it just seal, it just seals it. But I wanted to ask that question if there was any sort of value in

in doing it for the sheer fact that it may insulate. I got to ask these questions because that's how I learn. That's how my audience learns, right? No, I was a professor for years, so I know the drill. Cool. Okay, so let's go back to, so what is your involvement with that product? From what I understand, you were one of the ones that brought it to the market. Is that correct? No, no, I'm the guy who invented it. You invented it. Perfect. Yeah. So basically, I was a scientist at a national lab. Okay.

Okay. And this is now the early 1990s. And I had a grad student and I worked on it for four years. And we got it to work. And he got a PhD out of it. And we got a patent for it. And then I was a staff scientist at a national lab. And I didn't know anything about business. But turns out nobody wanted to license the technology from the lab. And so either I was going to die or I had to go do it myself. So basically...

I became an entrepreneur. So I started a company in 1997, starved for four years, then sold it to United Technologies, a carrier corporation. Okay. 2001. And then worked for them for a while, decided I didn't like that, went and became a professor. And then somebody approached me about taking the back out of carrier and starting it up again.

And so I did. And that's AeroSeal, as you know, right now. They've been around since 2010. But I started the company and made up the name literally in 1996. Okay. I would like to get a few minutes of background on that. So obviously when we go to invent something,

We are doing so because of a problem that's existing in a marketplace. And you're true. I can give you the spiel. I've done it a million times. Perfect. So what happened was I'm a scientist at a lab and we were doing research. Actually, this is going back even further. In 1978, I was a grad student and I was measuring the efficiency of fireplaces.

So you basically would take a house and turn it into a calorimeter. Basically take a bunch of little electrical resistance heaters, heat the house, and then turn on the fireplace and watch what happened to the use of electricity by the heaters. And one day we said, well, why don't we try it with the furnace? You know, we've been doing it with the heat. And what happened when we did it with the furnace, we got pretty crappy efficiency. And then we also figured out we were measuring the flow through the building.

while we were doing this. You know what a tracer gas is? Tracer gas is you put in a known flow rate of a gas and you measure the concentration of that gas. And then you can tell how much air is going through the building. Every time the furnace kicked on, the amount of air going through the building would triple. And so you'd wind up with, okay, what the heck is going on? And then it was like, oh, we figured out how to be duct leaks. So then I actually rolled forward a number of years and

And I convinced people to give me money. When you're at a lab, all you do is things you get people to pay you to do. So I convinced them to give me money to do a study in Sacramento on 31 houses where we measured carefully the energy use, HVAC energy use in these houses. We then sealed them, and then we measured it afterwards. And with duct sealing, we were getting like an 18% roughly savings.

Interestingly, you might like this being an HVAC guy, the savings for heat pumps was 35%. And the magical reason for that was that a heat pump is basically two pieces of equipment in one box. It's a heat pump, excuse me, an electric resistance backup. So when the load is too high, it switches from heat pump

to resistance backup. But by sealing the yucks up, the load went down and we got rid of virtually all of the electric resistance backup. So that's why the percentage savings was so much larger. And can I ask you what climate that was when you got rid of the electric? That was California. Okay. So what is sort of the design temperature in Sacramento there? I mean, I guess it doesn't really get that cold in Sacramento, right?

Well, it'll get to the 40s for sure. And it'll often in the middle of the winter hit the 30s. And in the summer, it gets pretty hot, right? It'll be 100 degrees outside in the summer. And I don't remember anymore. This is 1991. I have the papers. I could find it. But basically, I don't remember how much of our testing was winter versus summer because we did both. Okay. Let

Let me ask you this. Have you kept up with the advancements in heat pump technology these days and how we can use them in cold climates and all that kind of stuff? Sure. I'm quite familiar with that. Okay, cool. I'm actually on the advisory board for Dyke Incorporation. Oh, are you? Amazing. Cool. Very cool. So this technology is... Actually, I'm going to pause you for a moment because there's one key fact missing. When we did it that time, we did it with...

regular guys crawling in the attic, peeling back insulation and putting Pookie on or Mastic on the leaks. That's how we did it. That's where I was going next, but go on because you might answer some of my questions. That's what happened. That study, so we do the work, we publish the study and I thought I was a hero, right? Because I got all the savings and then the dealers, the contractors basically said, we will never do this again because my guys hate this work.

Because they have to crawl around in the attic. And it must have been in the summer, because I remember they were complaining about the hot attics. So what happened was, after that, so the problem I'm trying to solve is, okay, how do I go about making it that it's not such horrible work to do this? And I thought about going from the inside. So I look for technologies to be able to seal from the inside. And there's a company called Insituform.com.

And they're used for sewer pipes. They invert its cylinder, they roll it out in a sewer pipe and reline it. Okay. Then there were these little rolling things that would tape the inside of gas lines. The problem with both of those is that they can't deal with Ys and Ts and all of that kind of stuff. It's a mess. All right. So then I saw something in the paper.

In the Sunday paper in San Francisco, these guys, they had this big full-page ad for blowing this stuff in your duct system, for getting rid of dust mites and blah, blah, blah, blah, blah. It was air quality. And then fine print at the bottom, it says, and it seals the leaks. So I invited them to my lab, built the duct system for them, said, here, show me. And it didn't work at all. And I asked them questions, and I figured out that they didn't know anything.

So then I got my French grad student and he and I worked for three and a half years to figure out how to make it actually work. And then we did. So that was 1994. We needed a thesis 97 when I started the company. All right, cool. I was going to ask you about, cause here where I live in Toronto area, um,

Pretty much every home you go into, the furnace is in the basement. And then you have your A-coil or you have your... Yeah, I grew up in a house like that. I grew up in New York City with sheet metal ducts in the basement. And you've got one main trunk for return, one main trunk for supply. And then you have risers at various spots.

And those systems, I remember the argument that people made. They would say, well, it doesn't really matter because all the ducts are inside the house anyway. And over the years, I developed various counters to that, one of them being, well, if it's all inside the house anyway, why do you bother putting in a duct system? Right? The purpose of the duct system is to distribute the air to where you want it. Exactly. Yeah. And so if you're losing, and literally those systems on average,

were leaking 25% on the supply side and 25% on the return side. And so, like I was saying before, the temperatures were terrible coming out of the grills and the flows, particularly in the furthest grill. You cannot get heating or cooling out to the furthest bedroom, right? Because the air spends too much time in the duct

to get there. And so those buildings, and we had, there were papers that we wrote. This is going back 30 years, right? We did papers that looked at savings from duct systems in basements and looking at how much got lost through the walls of the basement versus came back into the house. And depending upon where your insulation is, you have insulated basement walls, you have insulated basement ceiling, blah, blah, blah, blah, blah.

There's actually where I was going to go with this is just because I was going to say most of what I see here in my area, everything is taped really in the residential side of things here. I don't see much mastic going on duck work, but I know mastic gets used quite a bit.

What I was going to ask you from obviously because the you were saying when you did this study, the guys did not like getting up in the attics and doing doing the duct sealing and all that kind of stuff because it was time consuming and all that.

Like the advantage of using a product like AeroSeal is we don't have hard labor to get this done. We don't need to go around and tape or paint mastic on. It gets blown in from the inside. Oh, it even gets to the top side of the ducts. Think about the ducts being underneath...

in your basement, right? Think about trying to get topside and seal those leaks. Yeah. So how long does it take? So how long does it take from start to finish for the average home, the average duct system? How long does it take to get that stuff in until it's ready to actually be used for the end user to have comfort in the home? Okay. So there's two applications. There's new construction and there's residential. What I can tell you

is that in new construction, they can do as many as four homes in a day. So they'll have to set up the system and they just go down in this construction process. And in one day, a crew of two guys will seal four homes. On the other hand, in existing homes, a lot of times it's they do one home a day. Sometimes they do two homes a day, but they don't get faster than that. And most of it is sort of the

drive time to get there, take the equipment out, set it up at the house and blah, blah, blah. That's why in new construction, they just, they could be prepping one while they're sealing the other one. So it becomes much more efficient. But in terms of- But the process of the, say you're set up, right? You're all set up and ready to go. How long does it take from start to finish to make sure all the ducts are sealed? How many on average is about an hour? Okay. Okay.

Yeah, that's, that's decent. And, and what's cool about it, this is like, all right, I'm a nerd. What's cool about it is it actually tracks the process as it's sealing and you can watch it. So you, you actually monitor duct leakage as it's being sealed. Correct. Right. Because what you're doing, you know, how much flow you're putting in, you know, what the pressure is in the duct system. So you can calculate the leakage every second. And then it just makes a little graph and the technician can see it seal and deter. And what happens is it starts out really fast.

and then it slows down as it gets near the end of the process.