Robin Jade Conde

PODCAST: Why is my house crying

Today’s show is about mysterious siding stains and air exchangers. Bill raises his concerns and clarifications about air quality as it is one thing that homeowners must start working with starting the fall season.

Reuben names and distinguishes the three types of mechanical ventilation: positive ventilation strategy, exhaust-only or point-source strategy, and balanced ventilation strategy. Tessa then adds the differences between these strategies, how they work and where they are most beneficial. She also discusses the multiple variables that affect the results when testing pressure and condensation inside the house. Bill and Reuben then share about interstitial condensation. 

They talk about recommendations on how to manage and test mechanical systems such as ducts, ERVs, and HRVs. They also discuss the right settings for machines and systems.



The following is a transcription from an audio recording. Although the transcription is largely accurate, in some cases it may be slightly incomplete or contain minor inaccuracies due to inaudible passages or transcription errors.


Bill Oelrich: On today’s conversation, we’re gonna lean into this third leg of the stool, this concept of what’s rattling around in our head.




BO: Welcome everyone, you’re listening to Structure Talk, a Structure Tech presentation. My name is Bill Oelrich alongside Tessa Murry and Reuben Saltzman. As always your three-legged stool coming to you from the Northland, talking all things houses, home inspections and anything else that’s rattling around in our head. Good afternoon Tessa. Good afternoon, Reuben. How are you doing today? 


Tessa Murry: Good afternoon.


Reuben Saltzman: Never better. How you doing, Bill? 


BO: Awesome. On today’s conversation, we’re gonna lean into this third leg of the stool, this concept of what’s rattling around in our head. And I wanna take something that’s rattling around in my head, I wanna quiz Tessa about it.


TM: Oh, oh. [laughter]


RS: You’re on the hot seat, Tess.


TM: Oh gosh.


BO: I’m preparing you for the hot seat, but I’m gonna give you just a second here to lean back and collect your thoughts. The reason this is bouncing around in my head is because we’re in the fall here in Minnesota, and by this time of the year, most people, if you have a piece of equipment in your house, called an air exchanger should probably understand if it’s working or not. Because it’s going to become a piece of equipment that’s turned on for the remainder of the year and all of the winter until spring shows up. Right? 


RS: Yeah. And I’d say if you haven’t already turned it on, you should have. Once you furnace starts running, your HRV should probably be running too. Or ERV, whatever we wanna call it. Air exchanger, you said Bill. Air exchanger.


BO: Well, I did that because nobody can understand when I say ERV. They think I say RV. [laughter] So I just went… I went broad with it, Reuben, to catch all these devices.


RS: Thank you. That’s good, Bill. It’s good.


BO: Do you have one in your home? 


RS: I do, I do. Mine is an HRV, a heat recovery ventilator. It’s this big box that’s mounted up next to the furnace in the basement. And it pulls air in, fresh air, adds it to the house and it takes stale air and removes it, and it helps to minimize condensation in my house.


BO: Tessa, you’re on the seat right now, that process is known as what? When it comes to this word we call ventilation? 


TM: What, the process of an air to air exchanger? 


BO: An actual process.


TM: I don’t know though.


BO: Dang it. I was trying to lead you to mechanical ventilation.


TM: Oh. Well, okay. [laughter] Sorry, I guess that was too obvious. I…


RS: Yeah, I was gonna say air changes per hour? I wasn’t sure where we would have gone with this.


BO: Alright, alright.


TM: Sorry, I failed question number one.


BO: The reason I ask is I had a contractor in my house a few years back, and they changed my fresh air intake, which was this gigantic 12 inch tube. It was like there was a door open in my basement, it was so cold in the basement. So I was getting some furnace work done and I asked them, I said, “Is this necessary?” And they looked at it and they said, “Well, it’s kind of big for the size of your house, you probably don’t need that.” So then they came and they were talking about air exchanges and things of that nature, and I was diligently paying attention, and then the contractor said, “Yeah, you know that’s fresh air. That’s make up air. We should probably get you some mechanical ventilation in here as well.” He goes, “You know what that is, right?” Like, “Oh yeah, absolutely.”


RS: Yeah, I’ve always been a big fan. Yes. [laughter]


BO: And I had no idea what the hell he was saying and why it was even necessary. So he took the 12 inch, they broke it, they left the big 12 inch and they broke it into two pieces. One was a 6 inch for just fresh air coming in, and then there was another one that had a damper on it, so when the furnace turned on and the fan was blowing, it kinda sucked in some fresh air from the outside and it dumped it into the ductwork so we could deliver fresh air mechanically to the entire house. Reuben shaking his head, he agrees that that was mechanical ventilation.


RS: Yeah, it’s one type of mechanical ventilation, and there’s three types. It sounds like what you did… Let me just repeat this back, make sure I got this right. He took a fan and he made sure that it is blowing air into your house. Right? 


BO: Yeah, but the fan that’s blowing air in is actually the furnace blower motor, and as it’s distributing air, there’s enough of a suction on a damper that opens that damper a little bit to allow cold, fresh air from the outside into…


RS: Okay. So it’s, yeah, the same thing. It basically it’s… It’s a fan that’s pulling air into your home, and we would call that a positive ventilation strategy where you’re bringing air in, but there’s no outlet, there’s no way that air is coming out. So you’re basically pressurizing your house. And then there’s another type of ventilation, which is called an exhaust only strategy, which is where you’ve got an exhaust fan, one or more exhaust fan. It’s usually going to be a really quiet fan, like Panasonic was one of the manufacturers of these fans, it’d be really quiet, it’d run at a really low speed constantly. It’d usually be upstairs in the hallway or it’d be in the master bath or… I can’t say master, the primary bathroom.


RS: See, what I did there, guys, I cut off myself, I was almost not PC there. It’d be in the primary bathroom, and it would always remove air from the house and that would be a negative ventilation strategy. So we’re counting on air leaking in all over the house. And then the third type of strategy is a balanced ventilation strategy. And that’s where you get a device, that’s meant just to bring fresh air in and exhaust stale air like I’ve got, the air exchanger that’s balanced. So now we’ve covered the three types.


TM: You know what? That’s a helpful way of thinking about it, Reuben, with positive, negative and in-balance. I’ve always, in my mind, I’ve always kind of thought of things as being categorized as either a balanced whole house ventilation strategy or a point source ventilation strategy. And it’s just a different way of looking at it, but it’s kind of the same thing that the point source ventilation strategy, you could use exhaust-only processes like Reuben was talking about, bath fans or a kitchen fan, something that you can turn on and off and just removes air from one location versus the balanced ventilation systems, which would be like an ERV or an HRV that’s connected to ductwork that runs throughout the house that brings air in, and exhausts air in this balanced system.


TM: And obviously balanced ventilation is gonna be the best thing if it’s properly installed and properly balanced and used and maintained well, but a lot of houses don’t have balanced ventilation systems. Most houses out there have point source ventilation strategies, mechanical ventilation strategies, like bath fans, kitchen fans like you were talking about, and that’s just because we’ve got a majority of houses out there are older housing stock and balanced ventilation is kind of a newer thing and it’s more expensive to do too typically.


RS: Yeah, exactly.


BO: Do you ever have a combination of a balanced strategy and a point source strategy? Do you see that when you’re inspecting houses? 


TM: Yeah. I’d say a lot of houses that… You’ll see balanced ventilation, like we are talking about, in newer houses with these HRVs or ERVs installed, because the tighter houses get, the more important ventilation is to maintain good air quality, remove contaminants from in the house, moisture, all of that, but it’s still important to have some sort of ventilation strategy for places like bathrooms. If someone’s showering or just air quality reasons, you wanna be able to turn a fan on and exhaust that air out of the bathroom, or when you’re cooking to turn on a fan above a range or kitchen or oven or something like that. And so most houses, new houses these days that do have balanced ventilation still have some sort of point source ventilation strategy as well.


BO: And that gets balanced out presumably by the fresh air intake? 


TM: Well, so that’s a good question. When you’ve got these point source ventilation strategies running, let’s say you’ve got a pretty airtight house and you turn on a bath fan, you turn on a kitchen fan, or you’ve got your clothes dryer running, which exhausts air out of the house too. That’s a really big fan. Your question is, where is that air coming from to replace the air that’s leaving, and most houses will have some sort of designated, basically hole cut in them that allows air from the outside to come into the house, and that could be a make-up air or combustion air. A duct that brings fresh air, and typically you’ll see, like you said, Bill, a six-inch duct, or in some houses it might be a little bigger, a little smaller, flexible duct that brings that air in and dumps it in somewhere in the basement of the house.


TM: But there are houses that don’t have that either, older houses, or depending on which climate zone you’re living in, where you don’t have this designated fresh air intake or combustion air intake. And so, if that’s the case, when you’ve got these exhaust appliances running sucking air out of the house, that air is gonna be pulled in through all these little leaks and cracks in the building envelope, around windows, around rim joist penetrations, doors, framing members, all of that. So the balanced ventilation system is really the best way to provide this ventilation because you’re able to filter the incoming air and preheat it coming in. So, if you’re in a cold climate, it tempers the air and it filters, instead of just being sucked in through all the cracks and leaks in the building envelope, like a lot of the housing stock that’s out there, what it does, how it brings fresh air in.


RS: And having a balanced ventilation strategy is gonna help reduce the potential for problems, and there’s kind of two types of problems that happen when you don’t have a balanced ventilation strategy, and it depends on which one it is. It’s kind of why I set the stage for this. Basically, if you’ve got a positive ventilation strategy where, like you said, Bill, you take a duct, you run it to the outside, you run it somewhere into the return plenum for your furnace, so every time your furnace fan runs, you’re bringing in air from the outdoors, you’re pressurizing your house, that air is going to leave your house.


RS: I mean, it’s gonna leak out somewhere, and the worst place for it to leak out is gonna be on the upper levels, where you’re gonna have the most amount of pressure, just because that’s where warm air tends to rise. It’s called the stack effect. And if it’s in the dead of winter and you got that furnace fan running all the time, and you’ve got that upper level much more pressurized, you end up with a bunch of condensation inside your walls ’cause air is trying to leave through gaps around windows and outlets, receptacles, light switches, all those little gaps air is trying to leave, and so it passes through there and then it hits the sheathing, and that’s a magical word. There’s a word for that, that space where you have that condensation. What is that, Bill? 


BO: Reuben, I think what you’re looking for is the fancy word I pulled out when I was doing some research for this podcast called interstitial condensation.


RS: Oh, you got to use it! Where’s my air horn at? 




RS: Yes.


BO: It’s the biggest word I’ve used in almost a month.


RS: Yes, that’s exactly it. And you can see signs of this on a lot of newer houses. If you look at their siding, and I don’t know why, but it seems to be the worst with vinyl siding, but you look at the siding, you see these little brown drip marks coming out of it, all over… Usually the north side of the house seems to be the worst. And you get all these little brown drip marks coming out, and that’s the result of condensation, interstitial condensation happening inside the wall, and then you get a warm day, all that frost that’s been accumulating ends up melting and then it drips out and it stains your siding. And it’s usually the result of improper ventilation. It means your house is pressurized.


RS: And not only that, but having an unbalanced HVAC system where you don’t have the right amount of supply and return registers throughout your house. The furnace itself can create a huge imbalance, and one of the better tests I’ve found to do, just to kinda guess at what your furnace is doing, this is not an official test, but just try turning your furnace’s blower fan on, and if you’ve got a basement and you’ve got a door to your basement, close that door almost all the way, and then hold a little piece of tissue paper up to that opening that the door makes, and if your system is properly balanced, the tissue is just gonna stay there, but if your basement is under positive pressure, then that tissue is gonna be blowing out, and if it’s under negative pressure, it’s gonna be sucking in. What we want is nothing.


RS: I’ve got a good video. I did a blog on this many years ago, where the house was under so much pressure that I got that door close to being closed, and I let the door go and it just closed all by itself, and it’s not that the door was out of alignment. There was just such an imbalance in the supply and return ductwork for the house that that basement was sucking a ton. So it’s a fun little do it yourself. Tess, what’s up? 


TM: I was just thinking, this is just… Pressures in houses is such a complex thing. There are so many factors that are involved in what the pressure is in a given area of the house at a given time. For example, what type of mechanical system you have. Is it a furnace? Is it running? How is the ductwork installed? Where are supplies? Where are returns? Which doors are open in the house? What’s the temperature inside the house? What’s the temperature outside the house? Is there wind? What supply and return registers have people closed? Is there a fan running in the upstairs bathroom? Is the dryer on? 


TM: All of these things will change the pressures and so, Reuben, as you’re talking about this little test you can do, I’m just thinking in my mind how you can get so many different results depending on all these variables, and how you conduct the test and when you conduct the test. And I think the biggest takeaway from this conversation is that if you’ve got positive pressures and you’ve got a lot of humidity in your house and it’s really cold outside, that moisture that’s inside the house will want to push out into the walls, and that can create problems with condensation in the house.


TM: Now, I don’t know if I’ve ever seen a house in Minnesota in the winter where it’s not a positive pressure upstairs. And so I wouldn’t say that it’s improper, I would just say this positive pressure thing is just an ongoing battle that we have in cold climates here, and the best way that we can try and prevent this problem, I wish I could say, “Let’s just make sure our pressures are perfect.” But that is just almost impossible, especially with how complicated ductwork and mechanical systems and ventilation strategies are. Half the time HRVs and ERVs aren’t even installed properly, or they’re not even in-balanced when they’re installed. People don’t know how to balance them.


TM: So how do we fix this problem? And really, I think at this point, it’s trying to build houses that are as durable as possible with materials that can hold moisture and are forgivable when they get wet and to monitor our humidity inside the house. So it’s like smart design, smart materials and moisture management because the pressure thing is so difficult.


RS: I’ll buy all that, Tess, but I will say something that can be done, and I recommend this every time I see it during a home inspection, is when you’ve got that duct connected to your return ductwork, a duct that goes to the outside, we always recommend disconnecting that thing because all it’s gonna do is pressurize your house and it’s not supplying combustion air to the room that it’s intended to supply it to and it ends up being a positive ventilation strategy. So I’d say we can agree…


TM: Yeah, I agree with you on that point.


RS: Disconnect that every time.


TM: And what you’re talking about is basically, if you’re a home owner and you’re wondering, is this something going on in your house, it’s basically like a, typically like a 6-inch flexible duct. You’ll see that goes from the room joist to your house in the basement and ties right in to the return ductwork at the furnace and the ceiling. That’s what you’re talking about. And disconnecting that from the furnace so that it’s dumping that fresh air from the outside just into the base.


RS: Yes, yes.


BO: You still want that air coming into your house, you just don’t want it connected to the return plenum is what you’re saying. We’re okay.


TM: Yeah.


RS: You got it, Bill.


BO: Going back to HRVs in testing. Reuben, how do you test ’em? Because what I’m hearing from Tessa is that this is really super complicated, and half the time it’s not even close to being balanced. So how do we test it and then convey to who’s ever gonna be in this house? “Oh yeah, things are working. It turns on and it does what it’s supposed to. I don’t know anything beyond that.”


RS: Yeah, as a home inspector or a home owner, man, I’ve heard so many different ways that you’re supposed to calibrate these things when they’re first installed. I’ve heard so many variations of it. So as far as I’m concerned, if the thing is running, I’m happy from a home inspection perspective. So really what homeowners ought to be doing is checking to make sure that it runs. If it’s supposed to be running, you’ve gotta turn on at the control. If you put your hand up to the side of the unit, you should feel a vibrating, you should feel motor turning. That should tell you that something is going on.


RS: Now that you know that something is happening, go ahead and pop the thing open, take a look inside, you’re gonna have two filters, a filter on the air coming in, a filter on the air going out, make sure they’re clean. And then you’re gonna have a core. It’s a heat exchanger. It’s a thing where air goes one way and air goes the other way, and the air sees each other but never actually touches each other and transfers heat. And those things can get dirty. Those need to be cleaned out periodically, manufacturers say once a year.


RS: And then finally go to the outside of your house and find the intake and exhaust. It’s gonna be these registers. It’s usually like a 6-inch metal grill, they’re typically kinda close to each other, they’ll usually be spaced somewhere about 6-10 feet apart from each other, if you got a really new house, they’ll even be labeled intake and exhaust, and just put your hand underneath them and check to make sure that one is pulling air in and the other is pushing air out. And that’s a pretty good test. You do that test and you’re doing better than 99% of other homeowners who never even bother to check it.


BO: Is that simply a control panel on a wall that you’re going and you’re turning this from off to on, or what’s a homeowner looking for to… And what’s the right setting? 


RS: You know, that’s a tough one, Bill. I’d say I’ve seen controls built into thermostats. You’ve got some really fancy thermostats out there that I can never even figure out how to use, and you gotta go into some menu setting and you can control your HRV there. At my house, there is a separate control module on the wall right next to my thermostat. It’s just a dial that I turn. And then yet at other homes, you’ll have that dial in the basement, and yet at other homes, it’ll just be a button right on the HRV or ERV unit itself, where you can adjust the runtime. You could have it run in low or high or off or some of them will give you a percentage of runtime where you can set it to run for 30% of every hour and it’ll cycle it on and off. So, unfortunately, there’s no quick answer to say, “Here’s where the control will be.” Those are some areas where your controller could be.


BO: Why wouldn’t they have some sort of humidity sensor on them that it’s like 90% humidity in your house, this thing should kick on and run until it goes down to 40% humidity or something like that? 


RS: Yeah, that’s a great question, Bill. I don’t know.


TM: Gosh, I feel like there might… I’m sure there’s that technology out there already, and I wonder if those smart thermostats have some sort of controls that can do that. That monitor humidity level in the house, and will switch on the HRV or ERV. I don’t know.


RS: Seems like a great idea.


BO: Tess if you had to guess the difference in humidity levels from a second story ceiling to the basement floor, how much of a gradient do you think there would be in the winter time? 


TM: Well, you know how I’m gonna answer this. What do I always say? 


RS: It depends.




RS: Tessa’s boring answer. Come on, give us a number, Tess.


TM: Boring answer, right. I wish I could give you an answer. Bill, just think about it, if you’ve got a house that’s really old and leaky, it’s gonna have a more extreme case of stack effect than a house that’s more airtight and sealed, so there’d be a bigger temperature gradient from basement to upstairs in a leakier house because you’re losing more heat, and the more heat out means more cold air in, so it’ll be much colder in the basement and much warmer upstairs in a leaky house versus a house that’s more airtight. And then if it’s really cold and dry outside, then it’s gonna be dryer in the basement because of all that cold dry air coming in versus all the warm humid hair from the house leaking upstairs. I was just thinking too, it also depends on occupant behavior. Maybe you’ve got someone who’s using the bathroom in the basement, it’s where they shower every single day, and there’s no one using the shower upstairs, and so there’s a lot of moisture and humidity being dumped into that base in the basement.


TM: Another thing could be maybe one house has a radon mitigation system and there’s a continuous fan running and pulling the soil gases out from underneath the slab of the house 24/7, which actually helps dry the soil beneath the house and helps reduce the humidity levels in the basement as well, versus a house that doesn’t, and it’s a high water table and there’s lots of moisture migrating up through the old slab.


BO: Variable.


TM: Another variable, yeah, so I don’t have a good answer for you, just more questions, I guess. [chuckle] Sorry.


RS: And Bill, my answer would be 9%.




TM: That sounds about right. Go to Reuben if you want a quick answer.


BO: 9%, I like that.


TM: Yeah.


BO: As far as you know, Reuben, Tess, these systems are whole home systems, so when the HRV turns on, it’s gonna be pulling from every place there’s a duct or a terminal, ’cause you can’t just… Or maybe you can have one bathroom that’s full of moisture and that, the HRV pulls just the moisture out of that room, are these systems that intelligent at this point? 


TM: Well, so there’s different ways to install these HRVs and ERV systems. You can have them ducted to every room in the house, you can have them kind of just servicing certain rooms in the house, and you can have them ducted so that basically what they’re doing is they’re pulling air out of bathrooms and kitchens and exhausting it to the outside. If you see a setup like that in a house, typically you’ll see a button in the bathroom or in the kitchen where it’ll say on/off and like a little picture of a house with arrows going through it, and that’s for the HRV system to turn on and pull air from that room specifically. So there’s… And I don’t have I guess the technical language in front of me right now for those different types of setups, but you can… There’s probably three, four, five different ways, maybe even more, to install these systems.


RS: But let’s be realistic, Tess wouldn’t you say at least 95% of them are gonna be connected right to the duct work next to the furnace? I mean, you take one duct, you put it on the return, another on the supply, and you call it done.


TM: Yeah, that’s what we see, I’d say, for the most part, you’re right, yeah.


BO: Because it’s like adding a whole… If you can fully duct it or if it’s a dedicated system, however you wanna describe it, that’s like adding a whole another set of duct work to your house specifically for that mechanical device.


RS: Yes, yes.


TM: Yeah, it is.


BO: And that’s cost that is added in the building price.


RS: Yeah, and not only that, but I don’t know, to connect that system and use that in place of bath fans I think it’s just dumb. [chuckle] I’ve got one bathroom on the first floor of my house, and it’s… Of course, it’s the one that everybody uses, it’s the one bathroom in the main living space, and there is no fan in that bathroom, there’s a button that will turn on my HRV for, I don’t know, 20 minutes or something, every time you hit it, it increases the runtime by 20 minutes, so press that button and it appears as though nothing is happening, but the HRV has kicked on, and I’ll just have to trust that there’s some air getting sucked out of this vent, maybe like a quarter of what would be happening if I had a fan. It feels very pointless, unsatisfying, you don’t hear the big whirr of the fan, and it surely had to cost more money to do it this way than it did to just put a fan in. Now, it probably didn’t, that’s probably why they did it this way, but it’s just, it’s obnoxious. Give me a fan any day.


BO: I just love when there’s these kinds of systems that everybody understands, well, they work as intended every time, and there’s no trouble if they stop working, and that’s exactly what we have [chuckle] with HRVs that the fans seize up and they haven’t been on for 10 years and… ‘Cause I’m sure you’ve found those, Reuben, some of those older units that the fan motors would just stop working or…


RS: Well, yeah, but what accompanies that so often is all kinds of other problems. You get condensation on all the windows, you get black staining, and you get mold problems in the attic, and frost and all this excessive condensation, all of that stuff goes hand in hand with an HRV that’s unplugged or has a seized motor.


BO: Do they flash in the basement when you walk down and they’re like, I’m the reason for all of that? 


RS: Just about, just about. I can just about see that flashing, yes, and I make a beeline for it and I go, “Ah, you’re the culprit, aren’t you? We’re gonna go have a talk.”


BO: Yeah.


TM: Bill, I was gonna add one thing, you asked earlier what’s the proper setting for an HRV or ERV too, and that’s a good question, and it’s something that I feel like we should talk about too, because when we’re doing inspections on new construction houses or we come across a house that has one of those things, we’ll try and explain to the buyers, the clients, what this thing is, just basic maintenance on it, like Reuben described, inevitably we’ll be asked, “Okay, well, what should we put the setting at?” And again, there is no right answer on this. Now, every house is gonna be different because it depends on how many people are living there, how much moisture they’re creating, how much cooking they do, how air-tight the house is, how big the house is, and so there is some sort of mathematical calculation that should be done when a house is being built to determine how many CFM, cubic feet a minute of air that house needs for proper mechanical ventilation based on I think ASHRAE standards.


TM: And I say that the best thing to do, though, if you’re living in a house with one of these systems is to just play around with it, and if you notice that you’re getting condensation on your windows or maybe there’s stale air in the house, or you’re noticing smells sticking around longer. Well, then crank it up. Have it run more. Right? And if you’re not having those issues, then you can turn it down a little bit. But most of the time like Reuben said, these systems will have a percent run time where they can run 20% of an hour, 40%, 60%, which would be continuous all the time, or they’re a high, medium, low, and so don’t worry about over-ventilating or under-ventilating. This is something that you can’t really, you can play around with it and you can be curious about it and find a setting that works for you in your house with your family.


RS: Yeah, that’s Tess’s answer. Now, here’s my answer. Set it to low.




RS: No. No. I…


TM: Start at low and go from there.


RS: No, I agree with what Tess has said. What I’ve always heard is that there is an energy penalty to running these things. They do take conditioned air and remove it from the house, and so you wanna try to keep it at the lowest possible setting you can where you don’t end up with any condensation on your windows. That’s the sweet spot.


BO: Last question, and I will stop this conversation, but is there a stated amount of air exchanges a house must have each hour or each day to remain healthy? 


TM: That is a good question, and I am not qualified to answer that. I don’t know what the ASHRAE… Is it 62.2 or 60.2? I don’t know what the current ventilation standards are, but there are standards for what every house needs.


RS: So you hear that, Bill? The answer’s yes.


TM: Yes, I don’t know what they are.




BO: Can you explain ASHRAE, Tess, just so if somebody was of the mind to jump on the internet and wanted to dig into that, they could? 


TM: Well let’s Google it because I can’t remember off the top of my head what’s…


RS: I’m going to American Society of Heating and Refrigeration.


TM: Yes.


RS: That’s all I got.


TM: Founded in 1894, it’s a global society, advancing human well-being through sustainable technology for the built environment. Focuses on building systems, energy efficiency, inner air quality, refrigeration, and sustainability within the industry. It stands for American Society of Heating and Air Conditioning Engineers.


BO: Okay, perfect. So these people know what they’re talking about.


TM: It creates standards. Yeah.


BO: If you wanna go do research, go to ASHRAE. And then go look for Joe Stiburek’s information and see how it compares. Can you spell Stiburek? 


TM: L…




RS: S-T-I-B-U-R-E-K.


TM: Yeah, there we go.


BO: That’s awesome. Joe’s stuff is awesome. For anybody who’s checked it out, you know he’s great and he’s funny, and he’s got a lot of wisdom. Okay, let’s put a wrap on this episode. It’s been pretty technical. I like technical when we’ve been away from it for a while, so that’s why I was so giddy to talk about mechanical ventilation and stuff. Everything we talk about we’ll put in the show notes. So Reuben, can you tell people where the show notes exist? 


RS: Yes, if you go to the site where we host our podcast, the official site,, it’s gonna redirect you to the podcast page on our website, that’s where we have all of the podcast episodes. That’s the official home of this, and you can find all the podcasts we’ve ever done there, and we’ve got a bunch of notes about who did the show with us. We usually have links to guests’ websites, and we have a transcription of all of the podcasts there too. So we put a fair amount to work into getting those show notes together, and it’s all again, found on the website,


BO: Great, awesome. We should get Joe’s website linked to this one. We should get Christine, Joe’s daughter’s Fight Club. What is it Tess? I can’t think of it.


TM: Yeah. The Building Science Fight Club. She’s got a great Instagram account where she talks about building science things, and she really dives into the details of wall assemblies and building science, mechanical, ventilation, all that sort of stuff in a very kind of easy to understand way. But building science can be a little bit confusing, but she makes it very accessible, I think.


RS: And not only that, but she was a guest on our podcast on January 25th of this year.


BO: Which was one of the funner podcasts we’ve done.


TM: We have to have her back.


BO: Yes, absolutely, absolutely. All right, everybody, you’ve been listening to Structure Talk. We’ve babbled on about mechanical air long enough, so we’re gonna cut this episode now, but thank you very much for listening as always. It’s me, Bill Oelrich, and Tessa Murry and Reuben Saltzman. Thanks for listening to Structure Talk.