00:00:06:17 - 00:00:27:07 Speaker 1 Welcome, and thank you for joining us on on your project Shepherd Construction Podcast. My name is Curtis Lawson with Shepherd Construction Advisors and along with my industry expert friends, I am here to guide you through these four key components of a successful project, which are demonstrated by the simple drawing of a house. The Foundation is proper planning. The left wall is your team. 00:00:27:12 - 00:00:50:16 Speaker 1 The right wall is communication and the roof is proper execution. Have all four of these components in place and your project will succeed. Whether you're building or remodeling a custom home, or if you're an architect or designer looking for inspiration, or maybe you're just interested in building science and high performance construction, you're in the right place. Please help us further our mission here by tapping that follow or subscribe button. 00:00:50:16 - 00:01:00:01 Speaker 1 Push that notification bell so that you know when our new episodes drop every week. And now let's get to today's interview. 00:01:00:03 - 00:01:25:17 Speaker 1 All right. Greetings, everybody. Welcome back to the Your Project Shepherd construction podcast. I am so excited about today's guest. And I'm going to give a very long intro here because there's a lot to say about him. So he won't get a chance to get a word in edgewise for just a minute. I am joined by Doctor Alison Bales, and Doctor Bales is the founder and president of Energy Vanguard, and he writes the Energy Vanguard blog through there. 00:01:25:19 - 00:01:46:02 Speaker 1 He also writes for a green building advisor, journal like construction, fine homebuilding magazine, and I'm sure lots of others. He's also a big time prolific poster on LinkedIn. Which is honestly where I first encountered him a few years ago. So if you follow him on LinkedIn, you'll get lots of good information to read. 00:01:46:04 - 00:02:05:04 Speaker 1 And he's a recently published author. His book called a House Needs to Breathe. Or Does it? Of which I have a copy right here. That book came out here just a few months ago, or in the last year. And he's also a speaker, so I first met him at passive House Austin, this spring where he came in and did a seminar. 00:02:05:06 - 00:02:18:05 Speaker 1 Had a great turnout and lots of great information there. So, Alison is all over the place. You can find them here. Has a lot of great information that he puts out. So, Alison, thank you for doing all that. And welcome to the podcast. 00:02:18:06 - 00:02:34:09 Speaker 2 Oh, well, Thank you. Curtis, I'm glad to be here. And, a couple things you you missed in the introduction. I went on, and I'm not a big deal, but, I live in Atlanta, and I am originally from Houston. I was born in Houston. 00:02:34:11 - 00:02:35:13 Speaker 1 Oh, I did not know that. 00:02:35:14 - 00:02:38:16 Speaker 2 I am a native Houstonian from from way back. 00:02:38:21 - 00:02:43:16 Speaker 1 Okay, I, I did see on your on your bio maybe on LinkedIn that you went to college in Louisiana. Yeah. 00:02:43:16 - 00:02:54:19 Speaker 2 When I was about ten years old, we moved from Houston to Louisiana. And so I mostly, you know, well, after ten. Lived mostly in south Louisiana. And then I went to college in Shreveport. So. 00:02:54:21 - 00:02:57:05 Speaker 1 So you been in hot. You been climates most of your life. 00:02:57:10 - 00:03:02:08 Speaker 2 You know, lived in Houston and then south Louisiana and then Florida for nine years as well. 00:03:02:13 - 00:03:26:06 Speaker 1 So all the places that are difficult to build, and it's sometimes difficult to live with all the things that we deal with. So, so Doctor Joe Seabrook, who's a well-known building science guy. He, referenced you as a well known trouble maker and a general pain in the ass. And Doctor Joe is usually a very, very, very mild mannered and never curses or never says a bad word or anything like that. 00:03:26:11 - 00:03:28:17 Speaker 1 So why would he call you a troublemaker and a pain in the ass? 00:03:28:18 - 00:03:48:10 Speaker 2 Well, I don't remember all the details of the discussion. It was on LinkedIn. You mentioned that I'm very active on LinkedIn, and that's very true and have been for a long time. This was about a decade ago, I think I posted something and there was there was a bunch of heated discussion about it, and Joe came in and said that about me. 00:03:48:10 - 00:04:03:15 Speaker 2 I don't remember the details, but I, I like the that quote so much, and I put it in my LinkedIn bio. I put it on the bio on my book and my, my title, my job title on LinkedIn is Chief Troublemaker, which I took from that quote. 00:04:03:17 - 00:04:29:09 Speaker 1 Yes. And that's that's where I saw the quote, too. So, our topic today is going to be, do your modification strategies. And as I mentioned, you know, we're in Houston, you're in Atlanta, you've lived in all these places. So humidity is something that we all always deal with. And this could be a different a conversation if you live in different parts of the country, say the north of the mountain West. 00:04:29:11 - 00:04:53:00 Speaker 1 But it's something that we deal with here. It's very relevant to a lot of our listeners and viewers. So, before we kind of get into start talking about what the strategies are to control humidity and humidity humidification, I just wanted to talk about why humidity is an issue in our homes. Why can't we just turn our our turn our AC on, let that manage our humidity for us? 00:04:53:05 - 00:05:24:12 Speaker 2 So a great question and good, good way to start this discussion. The, the the humidity comes from a different places. So the first thing you look at is on the indoors, people live in the house and we generate moisture that goes into the indoor air. Our breath contains lots of water vapor. So just breathing humidifiers, the air in the house and we we cook, we clean, we we shower, we have pets, we have houseplants sometimes. 00:05:24:12 - 00:05:44:05 Speaker 2 And all these things put put water vapor into the air. And speaking of houseplants, a lot of people may not realize this, but every drop of water that you put on houseplants when you're watering them is going to end up in the indoor air. Unless you take the plant outside before it all evaporates. But all that water eventually goes into the indoor air. 00:05:44:05 - 00:06:06:12 Speaker 2 So, yeah, something to consider there when you have houseplants. And so we're generating moisture indoors. And and you know, you mentioned other parts of the country like, you know, west where the outdoor air is very dry. You can deal with that moisture by ventilating. If you know something, you know, it's not too hard. Depends on other factors as well. 00:06:06:12 - 00:06:21:00 Speaker 2 But but you could handle the moisture with ventilation. And it's hard to get a house that's, too humid in a in a dry climate. Well, you can certainly do it, but it's a lot harder there than it is in the southeast where we are. 00:06:21:05 - 00:06:24:15 Speaker 1 And so those people are actually adding adding humidity with humidifiers. 00:06:24:15 - 00:06:42:22 Speaker 2 Yes. And the we've got, you know, the indoor generator there, we've got the outdoor air in the southeast which is humid. And the two ways that gets in one, if we have a leaky house, we if the house is not airtight, the building enclosure has leaks in it that allow that outdoor air to come in. It's bringing the water vapor with it. 00:06:42:22 - 00:07:06:02 Speaker 2 So in the summertime, it's not only bringing in the heat, it's also bringing in the humidity. And then if we have a ventilation system, I mean, not I'm not even talking about a whole house ventilation system, even just baths fans and the rain. Should you turn those on? You're you're sucking air through the leaks in the building enclosure and you're bringing that water vapor in intentional whole house ventilation. 00:07:06:02 - 00:07:32:17 Speaker 2 Same thing. You're bringing water vapor in and so we've got to deal with that. And air conditioners are great at removing humidity and some some better than others, of course, and older ones better than newer ones. Generally. So the first line of attack is to use the air conditioner because, you know, in summertime we're we're cooling the house and that they are passing over that cold air conditioner coil. 00:07:32:17 - 00:08:04:16 Speaker 2 The evaporator coil also, will give up its moisture because that cold, oil pulls the water vapor out of the air, condenses it, and and that dehumidifiers the air in the house. That works great on a 95 degree day when it's sunny and and hot, because you've got a lot of need for cooling. But what about that 80 degree day when it's not as hot outside, the air conditioner doesn't need to run as much to cool the house, which means it's not going to run enough to the humidify very well. 00:08:04:16 - 00:08:22:02 Speaker 2 So those cooler, cloudy, rainy days are the days when you really feel it inside the, that's generally, you know, what's what's going on there. And, you know, there's a lot of ramifications of that if you want to get into that now or whatever your next question is, we can go there. 00:08:22:04 - 00:08:41:13 Speaker 1 I was going to kind of point out that people, especially right now in Houston, it's been like 100 and over 100 degrees every month for the last few months. Like it's been it's been ridiculous this summer. And people here love to have their houses cold. And so their answer to this is, well, if it's not quite getting there, I'm just going to keep on turning it down. 00:08:41:13 - 00:09:03:19 Speaker 1 And I get that AC to 66 or 68 when it's 100 and 205 outside. But that actually can compound the problem. And first of all, the ACS aren't even designed to keep up with that much of a temperature differential. But just that, just keeping the AC cranked down all the time is going to create its its own whole set of humidity problems. 00:09:03:19 - 00:09:04:01 Speaker 1 Right? 00:09:04:06 - 00:09:29:04 Speaker 2 Absolutely, yes. And it's, it's a great way to compost a house or as a, you know, HPC contractor friend of mine in Jacksonville, Florida, says it's a great way to total a house. Another friend of mine in North Carolina recently posted some pictures on LinkedIn of a house where people were doing just that. They and they said that during the day they keep the house at 64, they keep the thermostat set at 64, and at nighttime they drop it to 58. 00:09:29:06 - 00:09:59:08 Speaker 2 Well, pretty sure that they aren't getting anywhere near 58. They may get close to 64, but, standard air conditioners can't cool the house that much. And the pictures that he showed indicated one of the problems with this. They were getting the house very cold, and the first picture he showed was the, the, probably the front door, the deadbolt coming through, and the outside of the deadbolt had condensation all over him. 00:09:59:10 - 00:10:28:06 Speaker 2 And he showed some other pictures, of water draining down from a light switch. And another one was condensation all over a light switch. Because you're you're getting these things really cold. And those are indications that you have some air leakage. So that humid air from outside is coming through the building enclosure and finding those spots where it's finding the really cold surfaces and water vapor loves cold surfaces so that it's, causing problems. 00:10:28:06 - 00:10:46:01 Speaker 2 Then also the, the drywall in that house was spongy because, you know, the the porous materials like drywall and wood just suck up lots and lots of water and drywall will get saturated and very spongy. You can put your push your finger through it easily if it's wet enough. 00:10:46:03 - 00:11:01:22 Speaker 1 Right? Which is why you said composting the house right there, that that wood, that paper, the actual gypsum is not going to it's not gonna have the problems. The paper on the back of the gypsum and it's the wood. It's those organic materials that are going to suck that water up and turn to compost. 00:11:01:22 - 00:11:19:04 Speaker 2 Well, that the gypsum itself is poor. It's a porous material. It will suck up a lot of water, too. And, you know, if you take a piece, you just peel the paper off, just take a place, a piece of pure gypsum and put it in a sink and it'll it'll dissolve in the water. So right when it's sucking up water from the atmosphere, it gets very wet and very, very soft. 00:11:19:04 - 00:11:50:12 Speaker 2 So, the, the the difference, though, between the paper and the gypsum itself is that the paper can serve as a food source for mold. So when you have microbial growth happening now, you've got spores for mold all over the place and other things that can grow. You've got lots of moisture. In that case, you got the food source and you can, easily get the, you know, the all kinds of microbial infestations inside the building enclosure, too. 00:11:50:12 - 00:11:55:00 Speaker 2 So you take the drywall off and you look in there and it's going to be a big mold factory. 00:11:55:00 - 00:12:17:22 Speaker 1 Which is why here, in the in the flood prone areas, in the flood zone here, our building code says that we can't use a paper bags, drywall. Below the flood elevation. So something does flood. That's just something that's not going to be able to to harbor, mold growth. No, the studs behind it is another story. 00:12:18:00 - 00:12:25:07 Speaker 1 I mean, we're supposed to use pressure treated lumber, but that's not going to stop the mold growth. It'll just stop the wood from rotting, possibly somewhat. 00:12:25:09 - 00:12:27:18 Speaker 2 It'll slow it down. It doesn't. Yeah, it doesn't stop it. 00:12:27:18 - 00:12:56:16 Speaker 1 As you know, I was actually in a house yesterday, on a consulting call. And when I walked in, the the thermostat was set on 68 again at 102 outside the thermostat set on 68. And she's complaining about mildewy smells, and we go in her master closet. There's actually water coming out of the electrical outlet. And that that, that outlets on an exterior wall on a south facing wall, in the house was recently, remodeled. 00:12:56:18 - 00:13:24:19 Speaker 1 It had brand new siding on the outside, but I don't I don't think they replaced the any or any sheathing there. So it's just you've got, you know, new fiber cement siding over an old RV that's probably not in great shape. But but, you know, she's she's we're forcing in extra moisture into the house through her, you know, maintaining that AC at a crazy temperature and that, that that moisture is finding every pathway it can through that wall. 00:13:24:21 - 00:13:52:05 Speaker 2 Yeah. And and so here's another thing to consider and let's, let's talk about dew point temperature now. Because in a humid climate that's a the temperature that you should really be paying attention to. And the weather apps now all have it. And and they even now will give you predictions that, you know, just like they show you, you know what the how the temperature is going to vary throughout the day, the regular temperature and the humidity, how it'll vary through the day. 00:13:52:05 - 00:14:19:07 Speaker 2 They will show you hour by hour what's happening with the dew point temperature, which is great because you can watch this, you know, like, if you want to cut your grass, but it's but it's just too nasty outside. You can look at the weather and see if you got any nice cooler, drier days coming. And as we had recently in Atlanta, though, the dew point temperature is very important because if somebody is keeping their house at 68, they and that's not that uncommon in the southeast. 00:14:19:09 - 00:14:50:23 Speaker 2 And the dew point temperature outdoors is 80°F. Then, 80 degree Fahrenheit air. So back up a little bit air with an 80 degree Fahrenheit dew point temperature means that if that air finds a surface that's below 80 degrees, you're going to get condensation. If you're keeping the house at 68 degrees, it's a lot easier to find for that air to migrate through and still have enough humidity to find surfaces below the dew point temperature of that air. 00:14:51:01 - 00:15:00:13 Speaker 2 So the the colder it is, and the bigger that discrepancy between the outdoor dew point temperature and the indoor temperature, the more likely you are to have these kind of problems. 00:15:00:15 - 00:15:20:00 Speaker 1 Also talk talk to us about how, the differences in indoor and outdoor temperature and indoor and outdoor humidity play with each other. You know that because, you know, temperature and vape water vapor, are always going to try to seek, seek equilibria. Right. 00:15:20:02 - 00:15:57:06 Speaker 2 Usually people think about humidity using the, the quantity called relative humidity. You know, 100% relative humidity means you are at the dew point temperature that you're you're probably going to see condensation on, on surfaces all over. But when you talk about relative humidity, the problem with relative humidity is that you also have to know what temperature it is and the you know, that, I have written a bunch about this topic because it kind of drives me crazy, especially when people who should know better say things like, oh, it's 95 degrees and 95% relative humidity. 00:15:57:08 - 00:16:23:12 Speaker 2 Well, that's not impossible, but it's extremely unlikely because 95 degrees and 95% relative humidity would be a dew point of like 9293 degrees. And the world record dew point is 95 degrees, Fahrenheit. And in the US our record is 94 degrees for. That's the highest dew point we've ever had in the US. Dew points in Houston. 00:16:23:13 - 00:16:43:04 Speaker 2 If you looked it up right now, probably 80 ish. So, I mean, imagine how humid it is out there with an 80 degree dew point. And then, add a whole lot more water vapor to bring that dew point up to into the 90s. So, yeah. So, you know, the interplay of temperature and relative humidity is very important. 00:16:43:04 - 00:17:07:07 Speaker 2 If you talk about relative humidity, you got to know, you know, what's the temperature. Because people say, oh yeah, it was 100% relative humidity. Well that's that's not unusual at all in Houston in the morning, if it's 75 degrees and you got a 75 degree dew point. But, when in the in the afternoon, if it's 100 degrees, you're not going to have, 100% relative humidity. 00:17:07:07 - 00:17:12:20 Speaker 2 So there's, there's a you always have to know what the temperature is that goes with the relative humidity. And you. 00:17:12:20 - 00:17:25:09 Speaker 1 Talk about. What is it that actually drives the, the, the vapor, the water vapor through that, through the structure, like pressure differentials and things like that. 00:17:25:11 - 00:17:51:23 Speaker 2 Yeah. So and and that was a crash course. Yeah. So in the field of psychometrics that's the, the term for the study of the mixture of dry air and water vapor. And there's a whole bunch of different quantities involved with that dewpoint temperature, relative humidity and dry bulb temperature. You know, what we usually just call temperatures is actually dry bulb temperature. 00:17:52:01 - 00:18:21:19 Speaker 2 And then there's also a wet bulb temperature. There's vapor pressure. There's enthalpy. There's about nine different quantities that you can plot on a psychometric chart. And the, the what drives water vapor to move from one place to another, technically, is the vapor pressure. You know, just like if the air pressure is higher on on one side of a wall than the other, and you have a hole in that wall, air is going to move from the high pressure side to the low pressure side. 00:18:21:21 - 00:18:44:19 Speaker 2 If you have vapor pressure, you know, water vapor pressure high on one side and low on another side of a wall. And then you have a place where the you know, let's say a porous material, so the water vapor can diffuse through that material. Then you'll have movement of that water vapor through that material. So the, that's the, the main thing that moves it. 00:18:44:19 - 00:19:06:08 Speaker 2 But in simpler terms, it's just that, water vapor, water in general, wet, you know, whether it's liquid or vapor moves from areas where, the concentration is higher to where the concentration is lower. Water vapor moves from from wet to dry is a simple way to think of. 00:19:06:10 - 00:19:37:07 Speaker 1 Right. And so as you as you talked about a minute ago, it's not it's, you know, it's not just, you know, when you open the door to the house, the air that comes in, although obviously that plays a part in it, but there's a lot of different pathways that that you have. The air can get into the house, whether it's through, a wall assembly, if it's not sealed, whether it's through a chimney flue that's left open, whether it's mechanical ventilation dampers that are left open or whatever, there's a lot of different ways that the humidity can enter the house. 00:19:37:09 - 00:19:48:22 Speaker 1 But even if all those little openings are sealed up, you know, it's it's always going to be fighting to find a way. Right? It's like this relentless battle that it's waging against your house. Yeah. 00:19:49:00 - 00:20:14:11 Speaker 2 Yeah. And, let's let's, let's clarify the two main mechanisms that transfer water vapor from one place to another. So we talked about vapor pressure and wet wet to dry. But there's two different ways that can happen. One moves a whole lot more water vapor than the other. And that one that moves a whole lot more water vapor than the other is air leakage. 00:20:14:11 - 00:20:43:19 Speaker 2 When when water vapor. So you've got humid air here and you get dry air here. Let's say you outdoors and indoors and you've got, air leakage pathways. That humid air going through those pathways brings all its water vapor with it. And you can get a lot of water vapor moving through that. If you have a lot of leakage, you know, significant amount of air leakage, which a lot of houses do that transfers a lot of humidity from outdoors to indoors. 00:20:43:21 - 00:21:07:14 Speaker 2 The other way that water vapor moves is by this process called diffusion. And so let's say you have a piece of, wood or drywall or concrete, you know, some porous material. And we build houses out of lots of porous materials. Yeah. You got the humid side here. You got the dry side over here. And the water vapor is going to go into that porous material. 00:21:07:14 - 00:21:34:01 Speaker 2 So individual water vapor molecules will move through those pores. And pop out the other side. That happens. But it's a much slower process. So when people talk about vapor barriers or vapor retarder, that's the process that you're limiting with the vapor retarder. Is is that diffusion the what stops the the bulk of the water from water vapor from coming through though is is your air barrier. 00:21:34:06 - 00:21:54:10 Speaker 2 So you need you need both. Well, you need an air barrier first and foremost. And you may or may not need a vapor barrier or a vapor retarder, depending on on where you are in a place like Houston, if you were to put a vapor retarder on the building enclosure, it would be on the outside because you were cooling dominated here in Atlanta. 00:21:54:10 - 00:22:39:12 Speaker 2 Well, I mean, before I go to Atlanta, in Minnesota, you would put the vapor retarder on the inside because the humid air is on the inside in winter time. In the summertime. Yeah, they have some humidity in summertime, but they, the humid air is not going to cause that much of a problem in summertime there with a depending on what you do for a vapor retarder, if you put a full blown vapor barrier like a, you know, sheet of plastic in a house, anywhere where they do cooling, and heating, then, you know, let's say that house in Minnesota has a sheet of plastic on the inside, and they do a lot 00:22:39:12 - 00:23:01:04 Speaker 2 of cooling where they're doing more cooling nowadays, that humid air in the summertime, if it gets into the wall and finds that cool drywall. But now you got a sheet of plastic there, it can't go through the drywall. It's going to hit that plastic. And and you get condensation is going to drip down right at the bottom plates probably, you know, get over the things where start growing things in there. 00:23:01:04 - 00:23:27:10 Speaker 2 So you have to you have to be careful with vapor retarder. And in one way, climates, you know, if you're doing all or mostly heating or all or mostly cooling, you can, you can put something on the inside or the outside. Where I live in Atlanta, we're going to be wrong half the year because we actually do more heating and cooling in Atlanta, something that most people don't know. 00:23:27:12 - 00:23:47:17 Speaker 2 So if we put a, vapor retarder on the inside, it's the wrong place. In summer, if we put it on the outside, it's in the wrong place in winter. You know, again, going back to the the main driver of humidity moving across the building, closure, air leakage. What we really need is a really good air barrier. 00:23:47:19 - 00:24:08:11 Speaker 1 Yep. All right. So that was kind of a quick primer. Again. You know our I know that we have some some builders and builder types that listening listen to us. But our, our podcast is really focused on the consumer. So I don't want to bury barium too much with, building science here. Which is easy for, easy for all of us to do. 00:24:08:13 - 00:24:31:20 Speaker 1 So you're somebody living in Houston, you're living in the South, you're out in Florida or whatever. Our concern is managing that umidigi that's coming into our homes, into our buildings. Now, this is going to be different on a nuke or the strategy to manage it, is going to maybe be different on a new construction versus an old home, new homes. 00:24:31:20 - 00:24:41:13 Speaker 1 You're able to, kind of control more of the variables, old homes. You're kind of at the mercy of what somebody did 40, 50, 100 years ago. 00:24:41:15 - 00:24:42:19 Speaker 2 Yeah. 00:24:42:21 - 00:25:05:06 Speaker 1 So different, different strategies. Sometimes, you know, so on a on a new home, you know, we start with a good building envelope, you know, the right, the right type of insulation, good quality windows, properly sized mechanical systems and things like that. Right. But on on old homes, you just can't. You can't ask those homes to perform like a new home. 00:25:05:06 - 00:25:06:20 Speaker 1 It's it's never going to do it. Right. 00:25:06:22 - 00:25:28:01 Speaker 2 Yeah. So, you know, as you said, different strategies for the different types of homes with the with the new home, you, you do, as good a building enclosure as you can. Air tightness is, is the one of the most important things to do. Well, we're not talking about that today, but the number one thing to do was to control the liquid water. 00:25:28:01 - 00:25:48:05 Speaker 2 You get a lot of rain in Houston also. And so you got to control the liquid water because that can cause problems faster than water vapor. Yeah. You got to make sure you got a good flashing and roof and everything. But on the water vapor side, the first thing to do is make sure you have a really good air barrier, as we mentioned before, because that's where most of the water vapor comes in. 00:25:48:07 - 00:26:09:03 Speaker 2 Have an airtight house. Even if you have a passive house that with super low air, air leakage, really, really good air tightness, you're still going to get water vapor in the house because you're generating it indoors and you're having to ventilate with outdoor air because, you know, with an airtight house, you want a good mechanical ventilation, a whole house mechanical ventilation system. 00:26:09:05 - 00:26:36:12 Speaker 2 And there's different ways to do that. You can do a ventilating dehumidifier, which brings in that humid outdoor air, mixes it with the indoor air and and then dehumidifiers it when necessary. The ventilating dehumidifier has, two ducts bringing air into it. One of those ducts goes to the outdoor. So it's bringing in outdoor air, and the other duct is bigger, and it's going to be bringing in indoor air. 00:26:36:12 - 00:27:03:18 Speaker 2 So it's recirculating indoor air. And it's also at the same time bringing in outdoor air. So those two airstreams come in because the dehumidifier the dehumidifier has a sensor either in the dehumidifier or separately, maybe on a wall somewhere. And we'll, decide when it needs dehumidifier. So it'll keep the, the humidity in the house where it needs to be based on, on the conditions in the house. 00:27:03:20 - 00:27:27:05 Speaker 2 And then there's the, energy recovery ventilator, which brings in outdoor air, and it's exhausting indoor air at the same time. So you have these two airstreams passing by each other. They don't mix. There's a membrane separating the two airstream, so they exchange heat. So on that hot summer day, 100 degrees outside, you're you're bringing the outdoor air in. 00:27:27:07 - 00:27:51:06 Speaker 2 You're exhausting the, indoor air to the outside. They pass by each other across a thin membrane, and the 100 degree air gives up its heat to the outgoing air. So it's getting pre cooled on its way in and in an ERV energy recovery ventilator. That membrane also allows water vapor to move. So the outdoor air is more humid. 00:27:51:07 - 00:28:12:16 Speaker 2 And the water vapor will diffuse through to the drier air stream. The the cool, dry air that you're sending to the outside. So you're retaining some of the, dehumidification you've already done by not letting as much water vapor come in, you're still adding water vapor to the house because you're not removing all of that water vapor. 00:28:12:16 - 00:28:47:00 Speaker 2 You're just transferring some of the water vapor to the outgoing airstream about 60%. Generally. And, you probably still well, you you you probably will still need a dehumidifier, especially for those those days, you know, the cooler, cloudy days, you know, the 80 degree days, the 75 degree days, the 70 degree days when the air conditioners not needing to do much cooling, the, but the ERV helps to reduce the amount that you're bringing in with the ventilation. 00:28:47:02 - 00:29:05:02 Speaker 1 A lot of this is going to depend on having a a mechanical contractor who knows what he's doing. Right. I think what, at least around here. And I'm sure this is the same in a lot of the country. A lot of the the guys who've been in that business a long time, not not trying to badmouthed mechanical contractors at all. 00:29:05:02 - 00:29:23:19 Speaker 1 There's a lot of great ones. But I think a lot of those guys came up using some kind of rule of thumb. Hvac strategy is, like, around here. I've always heard thrown around. It's 500ft² per ton. And that's how they size the air conditioners back in the day. And that's how a lot of them still size it. 00:29:23:21 - 00:29:56:03 Speaker 1 And their, their solution at the house isn't if the homeowner is telling them the house isn't cooling enough or it's too humid, well, they just increase the tonnage on the AC and that should cover it. Yeah. So talk to our listeners about, you know what? You know what? What are the right steps to right size that equipment, and what goes into it other than just the number of square feet per ton, because your your company does a lot of, Hvac sizing and specifications too, right? 00:29:56:05 - 00:30:05:21 Speaker 2 Yes. Yeah, we do full Hvac design, starting with the load calculation all the way through the duct design. And the ventilation system design as well. 00:30:05:22 - 00:30:12:03 Speaker 1 It's not an important new construction. It's very important also on retrofits. 00:30:12:05 - 00:30:43:15 Speaker 2 Yeah, yeah. And it's, you know, if somebody is having a new system put in. Well, the if for an existing home, if somebody has got, a system, one thing they can do right now, if the system, if the air conditioner is working well, is on, on those hot days, on what we call a design day, when the temperature gets up to the desired temperature for that location, like Atlanta has a designed temperature cooling designed temperature of 92°F. 00:30:43:17 - 00:31:01:00 Speaker 2 So in a day when it gets up to 92°F, if you and that's your design temperature, you go out, you, you can either time it by hand. I know people who have done that. You get a timer and you, you've, time. Well, you don't have to go outside. You can do it from inside as well. Your time. 00:31:01:00 - 00:31:26:09 Speaker 2 How many minutes per hour are your air conditioners running in the. You know, when you hit the the desired temperature and for a few hours afterwards. So how many minutes per hour is that system run? You can do it by hand with the stopwatch. You can also get data loggers that you put on there, and it'll it'll, record whenever the, the motor, the, the, you know, the, the air conditioner is running, though. 00:31:26:09 - 00:31:54:15 Speaker 2 It'll tell you how many minutes of run time you get. And I've done this, I've written articles about it. And if the, if the system is running only, say, 20 minutes an hour or even 30 minutes an hour when you're at designed conditions and for a few hours at first because I say add design conditions, but there's always the thermal lag because it takes some time for the heat to move through your walls and ceilings and floors. 00:31:54:17 - 00:32:21:19 Speaker 2 So, you want to look at it. You know what's happening in the hours after you hit that 92 degree or whatever your desired temperature is, and see, you know, how many minutes per hour is the system running? If it's running 30 minutes per hour, your system is about twice as big as it needs to be, because the the concept behind sizing the system appropriately is that you want it to be running close to full time, close to 60 minutes per hour. 00:32:21:19 - 00:32:47:13 Speaker 2 When you're at the design conditions. And and let me, let me define the design temperature. Now because we haven't said that yet. The design temperature for summer is the temperature that you're at or above only 1% of the time. So 99% of the time you are at the design temperature or lower, which means most of the time you're at part load conditions, not at your design load conditions only 1% of the time on average. 00:32:47:13 - 00:33:13:09 Speaker 2 There are years like this year where you're exceeding that design temperature. More than the 1%. And, we're seeing more and more of that. So, the, So that's what you can do if you have an existing house with an air conditioner that's still working. Well, you can time to see, you know, how how appropriately is the current system that I have seen? 00:33:13:09 - 00:33:42:14 Speaker 2 If it's running 50 minutes per hour, I'd say if you know 45 or 50 minutes per hour, you you've got the right size. If you're running one hour per hour, 60 minutes per hour with the air conditioner, and you're comfortable with that, then, then you can stick with the same size if, if you find. Well, in a year like this, when you're having a lot of, of the extreme heat days, then maybe go up a little bit. 00:33:42:16 - 00:34:10:03 Speaker 2 But there are other options as well we can talk about in a minute. Let's go to the the other side of this question for a new house. The load calculation that that we do is it's based on this thing called manual J, which is a protocol for calculating how much heating and cooling a house needs. It's from the Air Conditioning Contractors of America, aka and the, the software incorporates this protocol. 00:34:10:05 - 00:34:35:21 Speaker 2 We enter all the details about the house, not just the square footage of the the condition floor area, which is what that rule of thumb does. And you're just basing it on floor area only, which doesn't make any sense. We put in we put in all the details about the building enclosure. We out the floor area, the wall area, the ceiling area, the orientation of the house, the windows on each side of the house, skylights, if you have them. 00:34:35:21 - 00:34:58:07 Speaker 2 You know how much insulation is in the walls, how airtight is the house? And all these details go into the calculation, which gives you a pretty good number if you do it right. And even when you're absolutely strict about putting in exactly the, the, inputs the way you're supposed to, you still end up with some over sizing sometimes. 00:34:58:09 - 00:35:26:00 Speaker 2 A lot, though. Depends on on the house and everything, but generally I 1,520% over sizing. Even when you're strict about not not fudging any the numbers, not padding that. So that's the, the load calculation that you can do. And it. Well, you can do that for existing homes too. I mean, if you've got an air conditioner that's that's already on its way down and timing, it wouldn't make any sense because it's not performing then. 00:35:26:00 - 00:35:36:15 Speaker 2 Yeah. Then you can you can do a load calculation, on an existing house, you have to have some idea of what's in the house, or make some good assumptions. 00:35:36:17 - 00:35:59:17 Speaker 1 Yeah. And the occupancy even can make a difference there, too. If you've got a family of six in there versus just two people in the same size of the house, that's that's a pretty big difference. And, and, and just body temperature movement thing if things being used in the house, know how much, how much you breathing and pumping out. 00:35:59:18 - 00:36:02:19 Speaker 1 Hot air out of your lungs. Moist air. Yep. 00:36:02:21 - 00:36:42:22 Speaker 2 Yep. Yeah. Internal loads are important. They're generally a smaller part than the enclosure as well. It depends. If we're talking passive house, internal loads are a very significant part of your your total cooling load and heating load. So you really need to have a good handle on those. But for a typical house, the, the, the heating and cooling loads from the, from the building enclosure, from the air leakage, you know, the type of windows you have and all that, insulation or lack thereof, that that generally matters more than the internal loads. 00:36:43:00 - 00:37:09:14 Speaker 1 So on, on a standard whole house dehumidifier, you know, there's there's several, several brands out there. I won't touch a certain brand, although I've got my preferences, but, on a whole house, the amount of fires that are ducted, what's your take on ducting? Those, you know, those humidifier dehumidifiers, into the Hvac system versus having those as standalone systems outside of the AC, ducting? 00:37:09:14 - 00:37:34:22 Speaker 2 Yeah. Great question, great question. So we deal with this all the time. And, you know, the gold standard, David Tree Levin's term, he, used to work for one of those dehumidifier companies. Really smart guy. He calls the, independent ducting the gold standard for how to how to deal with the air going into and out of a dehumidifier and same, same is true for an RV or an RV. 00:37:34:22 - 00:38:06:14 Speaker 2 If you're using an air vent someplace, it recovery ventilator. Yeah. Independent ducting means that you can size those things perfectly for that unit. You've got one blower and one duct system. You don't always have space to do that though. And so sometimes we have to connect the dehumidifier or the ERV or both to the duct system for the heating and cooling and the, there are good ways to do that, and there are bad ways to do that. 00:38:06:16 - 00:38:29:04 Speaker 2 The the best way to do that would be to have, if you can have an independent intake for the, the dehumidifier. So remember I said, you know, in general, if you're doing a ventilating dehumidifier, you've got two ducts coming on the, coming in on the intake side, one bringing in outdoor air and the other bringing in air from the house that's recirculating. 00:38:29:06 - 00:38:56:01 Speaker 2 So, if you can have an independent intake, the bringing in the air from the house is recirculating and, and then you've got your dehumidifier air coming out the other end, if you're going to use the heating and cooling ducts to distribute that, that the humidified air, the best place to dump that air is into the supply side of the heating and cooling system or, well, let's say cooling system, because we don't generally dehumidifier when we're heating. 00:38:56:03 - 00:39:15:01 Speaker 2 Right? So, and the reason for that is if you, if you take that dehumidifier there and a lot of people think this, they think, well, the air coming out of the dehumidifiers warmer. Right. So I should dump that into the return so it passes through the air conditioner and gets cooled off before it goes to the house. 00:39:15:03 - 00:39:36:00 Speaker 2 What you're doing in that case is increasing the energy bill for the homeowners, because now you're using your dehumidifier for for all or most of the dehumidification because you're dumping the dehumidifier humidified air into the air conditioner. So when that dehumidifiers running the air conditioner has very little dehumidification to do. 00:39:36:02 - 00:39:39:05 Speaker 1 Right? You're kind of 3D humidifying the air. 00:39:39:07 - 00:40:05:15 Speaker 2 Yeah, yeah. So yeah, you're cooling off the dehumidifier there, but you're also making that dehumidifier run more because now the air conditioner is doing less of the heat modification. The humidifier will do more. So yeah, best places to put it in and on the supply side. And this can be very tricky. You've got to get the you know, the duct system has to be designed properly and size properly. 00:40:05:17 - 00:40:38:05 Speaker 2 You know, depending on the size of the dehumidifier and the air conditioner, you can mess this thing up really badly. I know that, you know, a contractor in Florida, Jerry Garcia, who came on one existing home job where, I mean, he didn't really have much of an option, for where to put the the dehumidifier there. So he put it on the supply plenum and the the supply shrunk line, and everything was such that most of that dehumidifier went straight down the, the trunk line and went into one room, which happened to be the primary bedroom. 00:40:38:05 - 00:40:40:20 Speaker 2 And that is not where you want it to go. 00:40:40:22 - 00:40:42:19 Speaker 1 So they didn't like that extra warm air coming out. 00:40:42:19 - 00:41:06:19 Speaker 2 Yeah. Yeah. So you have it requires a lot of, forethought and, understanding of how this works to get it done. Right. But the other thing is when you when you have a house, you know, especially if you have a new house that's got good air tightness, it doesn't have to even be passive house. But if it's fairly airtight, you don't have as much dehumidification to do. 00:41:06:19 - 00:41:28:14 Speaker 2 The dehumidifier is not going to run all the time. And like I said earlier on the on the hot days, you know, the 95 degree days, 100 degree days, that dehumidifier is not going to be running at those times. It's going to be running at nighttime or on the the cloudy cooler days when it's 80, 85 degrees out, 75 degrees that that's when you get more dehumidifier run time. 00:41:28:16 - 00:41:56:11 Speaker 2 And so putting that that heat back in the house from the dehumidifier actually helps dehumidifier better as well, because that will make the air conditioner run more. And so you get the modification more medication from the air conditioner as well. And, and you can do all this without making the house cool and clammy. And going back to that earlier discussion about the house with the condensation on the deadbolt, that's probably what they were trying to do. 00:41:56:11 - 00:42:13:07 Speaker 2 I mean, you know, when the humidity is too high, people aren't comfortable. And so they the only control they have is the thermostat. So they keep turning the thermostat down, and that just makes the house cool and clammy and composts the house sometimes if they keep it like that too long. 00:42:13:09 - 00:42:37:00 Speaker 1 Yeah, I like to, to duct, are the modifiers that we install. I like to duct them completely independent. And you know, with that at the, at the outlet of the, of the humidified air, if it's a two story house, maybe dump it into a, a higher ceiling somewhere or that. Yeah. Someone's not getting blasted with, with warm air in a room. 00:42:37:01 - 00:42:45:17 Speaker 1 But I kind of get that, that outlet away. Just to increase the comfort level for people to kind of spread that air out a little bit. 00:42:45:19 - 00:43:14:00 Speaker 2 Yeah, yeah. And we've that's what we've done in some of our design. So you have to think carefully if you doing independent ducting like you just said, you have to think carefully about where you're going to put that dehumidifier there because it's coming out warmer and you don't want that getting into the occupied zone where the people are before it's thoroughly mixed with the other air in the room because, you know, once it mixes with the air in the room, it's coming to a more reasonable temperature. 00:43:14:02 - 00:43:22:12 Speaker 2 And it's not going to bother people. But if if you put it right over there, La-Z-Boy, and blow it right on them, they are not going to be happy. 00:43:22:14 - 00:43:48:05 Speaker 1 I've also heard from a couple of different, people, and, I'll get your take on this, that ducting a dehumidifier through an Hvac system, doesn't always work great because, some of those duct runs are long, and the edifier just doesn't have enough. Well, you know, enough room to to draw through this. There's some of those longer duct runs. 00:43:48:07 - 00:43:49:15 Speaker 1 What's your take on that? 00:43:49:17 - 00:44:14:21 Speaker 2 So, yeah. So if you're, if you're putting the dehumidifier there into the supply trunk line, for example, the, and if you have a big duct system, let's say you're, you're dehumidifiers moving 200 cfm, but your duct system is made for moving 1200 cfm, so that's not a lot of air in those ducts. And, yeah, it's going to move through slowly. 00:44:15:02 - 00:44:31:12 Speaker 2 But if the ducks are tight, if the ducks are sealed, then it will come out. I mean, you put you put a, you know, a cubic foot of air into that duct system and then another cubic foot of air behind that and another cubic foot. If you keep pushing air in the duct system, it's got to come out somewhere, right? 00:44:31:14 - 00:44:40:15 Speaker 2 As long as it's tightest is will be coming out. And then when the air conditioner kicks on, it'll it'll push the rest of it out of it. There's still some in there. 00:44:40:17 - 00:45:08:11 Speaker 1 Another question I had for you was, I've heard a lot of contractors and energy folks here in our area. At least maybe rely too much on, bathroom exhaust fans, I think. But, and this is my opinion. So give me give me yours, please. You're more of an expert than me. But for me, about bathroom exhaust, fans are kind of meant to remove the bulk humidity from those areas. 00:45:08:11 - 00:45:30:15 Speaker 1 So after you get out of a shower, if the or if in a laundry room, if the clothes dryer is running and there's hot, humid air from a clothes dryer present, things like that, they're great for taking care of those situations, but they're not really. Well, they're definitely not the modification. They're just extracting. That moist air, right? 00:45:30:20 - 00:45:55:09 Speaker 2 Yeah. And you're exactly right. The the, you know, bath fan is meant for exhausting the air, you know, when somebody's taking a shower or a bath and you've got that, that warm, humid air filling up the bathroom, you want to exhaust that out so that it doesn't get in and mix with the house and or, you know, stay in the bathroom and start growing mold on the walls and you want to you want to get that out. 00:45:55:09 - 00:46:31:09 Speaker 2 That's what the baths. That's one of the purposes of the baths in. So if you, if you rely on the baths and for whole house ventilation in the summertime in the humid climate like Houston, you can get in trouble because you are you're exhausting air from the house. It's, you know, and you know, where the, you know, that air is going, but where the air is coming from because, you know, every cubic foot of air that goes out of that exhaust fan means there's a cubic foot of air coming in somewhere through through the leaks in the house. 00:46:31:11 - 00:46:49:12 Speaker 2 You don't know exactly where and, you know, it's going to be connected with outside. So it's bringing in the humidity from outside as well. And if you have an attached garage, it's also bringing in air from the garage because the, air from the garage is generally not the kind of air you want to be bringing into your house. 00:46:49:17 - 00:46:50:12 Speaker 2 Right. 00:46:50:14 - 00:47:17:22 Speaker 1 All right. And last thing I want to touch on here is, just being being realistic with what we expect out of our air conditioning systems. Again, we're talking about these extreme conditions that we're dealing with right now. If you're listening to this, you know, in here in the summer or the early fall of 23, where when this is happening, but again, it's just talking about being realistic with what we're asking our systems to do, talk about. 00:47:18:00 - 00:47:33:11 Speaker 1 And we've touched on this a little bit, but talk about kind of the dangers of, of running that, that system too much and, and kind of, you know, what are the dangers of, of, not being realistic with your set points is what I'm trying to say. 00:47:33:13 - 00:47:59:08 Speaker 2 Yeah. Well, so if you lower the thermostat, the 68 or 60 4 or 58 and don't do that, you're keeping. Yeah. If you're keeping the house really, really cold and, you know, we've we've mentioned those problems, you're going to get condensation. You're going to be getting moisture coming in through the leaks in the house. You get water draining out of the light switches, out of the baths. 00:47:59:08 - 00:48:25:17 Speaker 2 And I've seen I've seen video of water draining out of a bath and duct into a bathroom. And so, yeah, definitely not a good idea to try to solve the problem that way. The best way is to find out. Well, you know what? What can I do to minimize the amount of water vapor in my house? And then if it's if the air conditioner is not handling the humidity by itself. 00:48:25:19 - 00:48:48:06 Speaker 2 Well, you know what? How can I set up a dehumidifier to handle this? And there are, as you mentioned, there's whole house dehumidifiers which are ducted. And they're in addition to the, being ducted and allowing you to treat a whole house or big portion of a house. They also are way more efficient than those little room dehumidifiers, and they generally last a lot longer. 00:48:48:08 - 00:49:08:16 Speaker 1 So yeah, they're gonna be more energy efficient as well. You know, one last thing I wanted to mention on that is that, if you have a humidifier. You can set your AC at 73, 74, and it's going to feel cooler if the air is drier. Right? 00:49:08:16 - 00:49:09:20 Speaker 2 So, yes. 00:49:09:22 - 00:49:28:19 Speaker 1 You don't have to set your AC down as low to feel comfortable. And that's an argument that we have with clients all the time. Is, is that they say, no, I have to have my AC on 70 or 68 or whatever it is. And we say, well, what what kind of system do you have now? Are you in an old house? 00:49:28:19 - 00:49:48:04 Speaker 1 Do you have it emit fire? No. Okay. Well, on your new house that we're building for you that you're about to move into, just try it for me. Try setting your AC on 74. Try keeping your do your modifier at, you know, 60% or 55% or whatever and see how you feel. Right? And if you're not comfortable, you know, knock it down a degree and see how you feel. 00:49:48:04 - 00:50:01:20 Speaker 1 But, you know, on new construction, it's a struggle to get people to understand that what what they're getting now is much different than that 1950s ranch that they've been living in until now. 00:50:01:22 - 00:50:23:12 Speaker 2 Yeah, yeah. And, you know, going back to something I said earlier, a lot of times people have only one control that for their comfort in the house. And that's the the temperature, you know, the thermostat, they can set the temperature higher or lower. And and that's that's a oversimplified way of dealing with comfort because comfort depends on way more than just temperature. 00:50:23:12 - 00:50:42:16 Speaker 2 And we're talking about temperature and relative humidity. And when you factor in the relative humidity, yeah, if you can keep the the temperature a little bit higher in the relative humidity lower, then you'll be more comfortable. And a third factor of course is air movement. If you have, you know, like ceiling fans, I love my ceiling fans. Me too. 00:50:42:18 - 00:50:53:16 Speaker 2 But with the with, you know, I generally keep my air conditioner at about 74 in the summertime. And you know, if if that feels too warm, all I do is turn on a ceiling fan and, that perfect. 00:50:53:21 - 00:50:57:20 Speaker 1 So it's amazing just just what air movement will do for you. 00:50:57:22 - 00:51:22:12 Speaker 2 Yeah. And, you know, I realize everybody's, internal thermostat is different. We all have different metabolisms, and, you know, different feelings of comfort depending on the conditions. So there's certainly something to that. And some people, some people just will never be comfortable, even, you know, 72 degrees and 40% relative humidity is that's going to be too much for them. 00:51:22:12 - 00:51:33:09 Speaker 2 Probably. So, you know, those people need to make sure they have a really good building enclosure and some good dehumidification. Yep. 00:51:33:11 - 00:51:49:11 Speaker 1 All right. Well, I think that wraps up our discussion for today. Again, thank you so much for joining me. It's been a pleasure having you on. And I hope we can do it again sometime. If people want to, buy your book, which I recommend they do, I'll hold it up one more time here. People want to buy the book. 00:51:49:11 - 00:51:51:04 Speaker 1 Where do they find it? 00:51:51:06 - 00:52:14:22 Speaker 2 They find it at Energy Vanguard store.com. My company's name is Energy Vanguard. Our regular website is Energy vanguard.com. We have a newsletter comes out every week. So you can subscribe to our newsletter there as well. I generally have one new article a week that goes into the newsletter and other stuff as well. The the website to buy the book is Energy Vanguard Store comm. 00:52:15:00 - 00:52:17:20 Speaker 1 Awesome. Well, thank you so much for being with us. 00:52:17:22 - 00:52:22:10 Speaker 2 Oh you're welcome. I'm happy to be with you. And, thanks for all you do, Curtis. 00:52:22:12 - 00:52:24:11 Speaker 1 Hope to see you soon. Are you here in Houston? 00:52:24:12 - 00:52:26:03 Speaker 2 Yeah. Looking forward to it. 00:52:26:05 - 00:52:53:09 Speaker 1 All right. Take care. If you found this helpful, enjoy listening. Please support us by liking and subscribing here on your podcast platform. And also join us on our YouTube channel. We want to continue to bring you high quality content and expert guests, and your support truly helps us to continue this journey. If you have any questions for me or my guests or any feedback for us, you can email us at podcast at your project shepherd.com. 00:52:53:11 - 00:52:54:04 Speaker 1 Thanks again.