The HRV Guy: Why Air Quality Matters
Have you ever walked into a room that feels stuffy, oppressive even, and thought, "Something doesn't feel right in here"?
It's a sensation many of us experience but tend to dismiss.
What if we told you that sensation might not only be an inconvenience but a potential health risk?
Today we’re discussing air quality and ventilation, topics that are often overlooked in home construction and renovation projects. We're unpacking this critical subject with the help of Joel Seagren, the national MVHR Solutions Engineer at Fantech, who unravels the mysteries of airflow, air quality, and their importance in building homes.
The Hidden Cost of Poor Air Quality
When people talk about creating healthy homes, discussions usually revolve around the more tangible aspects of construction like thermal comfort, noise reduction, and safety. But what about the invisible menace: air quality? Poor air quality has been linked to reduced lifespans and lower standards of living. It's a silent factor that slowly but surely affects our health—think of it like eating unhealthy food. The consequences might not be immediate, but they build up over time. Joel explains why ventilation is essential, not just for comfort but for health, and why he's devoted a decade to this vital aspect of human well-being.
Navigating the World of Ventilation: HRV vs. ERV
Understanding the nuances between different types of ventilation systems can be a little confusing. Joel simplifies this for us. HRV (Heat Recovery Ventilation) and ERV (Enthalpy Recovery Ventilation) are two systems aimed at enhancing air quality in homes. HRVs focus on temperature recovery, ensuring your home's climate stays stable, whilst ERVs add moisture control into the mix, making them ideal for both high humidity and extremely dry climates. Think of HRVs and ERVs as systems designed to manage not only temperature but also humidity, ensuring that indoor environments remain not just comfortable but healthy.
The Reality of Modern Homes and Ventilation
Passive houses, known for their airtight structures to conserve energy, highlight the necessity of proper ventilation. Without it, you risk creating an environment conducive to mould, mildew, and poor indoor air quality. Joel emphasises that the real magic of mechanical ventilation is its ability to dilute contaminants and maintain a constant stream of fresh air, thus safeguarding the structure's durability and the occupants' health.
It’s not merely about answering the "how many air changes, what’s the magical number?" It’s about understanding that without controlled, adequate ventilation, even the best-built homes can become breeding grounds for respiratory issues.
Why We Need to Talk About This
Yes, we’ve built homes for decades without much thought for ventilation, relying heavily on the opening of windows and natural airflows. But as Joel points out, with urbanisation comes noise, pollution, and security risks that compromise this age-old method. The crux of the matter lies in balancing air tightness with controlled ventilation, ensuring that our living spaces are both energy-efficient and healthy.
Isn’t It Time to Reconsider?
This isn’t just some futuristic concern reserved for the overly cautious or the inherently wealthy. It’s a discussion affecting everyone, especially those in urban areas where external air quality can be compromised by pollution and other environmental factors
As builders, architects, and homeowners, we have the opportunity and responsibility to avoid cutting corners when it comes to installing proper ventilation systems. In the long run, it’s not just about preventing issues like mould, but about ensuring your home is a safe haven for years to come.
By understanding and improving air quality in our homes, we not only contribute to our well-being but also to the global movement towards healthier living environments. As Joel sums up, “Ventilation is de-risking your project.” So, let’s start asking ourselves: Can we afford not to pay attention to it?
This conversation with Joel gave us plenty to think about and a clear path forward—embracing the inevitable journey towards healthier, more sustainable living through proper ventilation. So next time you step inside your home, consider the air you're breathing. It matters more than you might think.
LINKS:
Thanks to Hip Vs Hype for having us
Connect with us on Instagram: @themindfulbuilderpod
Connect with Hamish:
Instagram: @sanctumhomes
Website: www.yoursanctum.com.au/
Connect with Matt:
Instagram: @carlandconstructions
Website: www.carlandconstructions.com/
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Matt: [00:00:00] So Joel, when everyone talks about healthy homes, we usually talk about thermal comfort, noise, vibrations, and air quality. Why do you care so much about air quality?
Joel: Yeah, so air quality is obviously a fundamental part of human health. So we know there's plenty of research from, um, other countries, other institutions that show, uh, poor air quality leads to reduced lifespans and poorer standard of living.
Matt: And how did you get into that? Like what made you focus on air quality as a, as a job?
Joel: I wanna say I stumbled into it. So I, uh, started at Fantech probably a bit over 10 years ago now. Started in a slightly different space. Obviously fan tech's a ventilation business, so it was about that. But first and foremost, in those early days, it was about the people I was working with, their great people.
But I very quickly found myself in this space where we looked at providing better air quality solutions and high [00:01:00] performance space. And that's kind of what I love.
Hamish: What's your background?
Joel: Mechanical engineering and then a, a master's in some sustainable building design.
Hamish: So you work for Fantech and you know, I obviously want to give them credit because obviously you are sitting here right now and we use a lot of their products.
So fan tech's a massive company. So can you maybe just very high level touch on like who Fantech is?
Joel: Yeah. Okay. So fan tech's a business that's been around more than 40 years now, more than 50 years actually, uh, and has always been in that air movement space. I. We don't compete with the Mitsubishis or the Deacons.
We don't do split systems or VRV type stuff. We work in the air movement, air quality space. We do some attenuation products and we do do a bit of large, uh, air handling, heat recovery type equipment. But, um, it's a business that's really kind of, knows it's knitting in that space and we've become a pretty proud, successful business there.
Matt: So you are the, [00:02:00] the Zender component of Fantech, is that what you are?
Joel: Correct. Yeah. So I'll loop that more as the, um, residential home ventilation space. The HRV guy, it's the H HR V guy is the HR V guy. Yep. And so that is a, definitely a niche within Fantech. Yeah. It's a growing niche. We, we've, we've recently been bought out by a, um, a UK business that has, um, definitely lots of expertise and capacity in that home ventilation, HRV space.
And so it's a really good
Matt: synergy. You can maybe not answer this question, but since you've been bought out. And you've just said that they have experience since that they have their own HIV that they might make Zenda redundant. Definitely not.
Joel: It's a complimentary product. Okay. So, um, it expands our offerings, which is a great outcome and there's lots of enthusiasm about them.
I. It's a good trained answer. It is a good trained answer, isn't it? So, yeah,
Matt: the reason I ask is like, we're so I'm Zenda or nothing, me [00:03:00] being selfish, you like, I was like, oh shit, what happens then? Yeah, like, yeah, like, so there is the security because at the end of the day, like Zenda products that we use, like they're by far the best.
Joel: They
Hamish: are the premium player in the market. But I mean, I think that's, it's good to hear that there are other products coming in because I think if we're gonna roll out. And we'll, we'll talk about performance construction in a second, but if we're gonna roll out this stuff on a broader scale, not everyone can afford the Q series.
Exactly. Yep. You, you need tiered strategy.
Matt: But I'm gonna go the opposite way, is that, that people just don't value it enough and don't understand the air quality. So then when you have the best. Like sometimes we need the best in these things.
Hamish: Yeah. Okay.
Matt: So it's air quality. We're not talking about the stone that hey, you can substitute something else that looks pretty good.
Yeah. This is your air quality. This is
your
Hamish: health. I'm gonna, I'm gonna argue that from another side, saying something's better than nothing. You know, if we can roll out better ventilation across. It's like, you know, okay. It's like the seven star thing, right? If we built every single home to seven stars, actual seven stars documented, and then [00:04:00] verified seven star homes is gonna make such a bigger, uh, difference in our building stock than if you and I built five passive houses a year.
Mm-hmm. Yep. So if our homes were properly ventilated, now who gives a shit what? Well, to a degree. What ventilation systems in there. As long as there's a ventilation system in there that's doing what it's meant to do, filter fresh air Yep. And extract used air. Yep. Then
Joel: I don't think that's a bad thing.
You are right in that context. It is about the filtration and the reliable air flows. What Spending more buys you is higher efficiencies and lower noise levels, better controls.
Matt: Okay, so let, let, I reckon we should break this down a little bit. So. I want to go to control versus natural vent slash I think that's something we should explore first, because you were talking about requiring mechanical ventilation with these and will they, they will range from a, a ceiling fan, which is what most people understand, um, in, in extraction fan in a sort of a bathroom.
That's what mechanical [00:05:00] ventilation is and we're all familiar with that, but then there's natural ventilation. So will you just sort of touch on the difference between them two first before we jump too much into. The mechanical side of things. Yeah.
Joel: Okay. So our current building code is really built up around mechanical extract from wet areas.
Um, laundries, bathrooms, toilets, uh, mechanical extract from kitchens. Yeah, N CCC 2020 twos made that really clear. That's now gotta be externally ducted. And these are for, uh, moisture removal, but also for some odor control there. What we don't have is a, any guidance around mechanical, uh, ventilation as a supplier solution.
So fresh air to habitable rooms in a class one building. Yeah. Oh, and a class two. So a apartment
Hamish: building. Yeah. So just, just to confirm, just so I've got that in my head. Their code at the moment only talks about extract only mandates, extract. Uh,
Joel: correct. And, and mandate is [00:06:00] probably even too strong a word.
Okay. Suggests salutes to correct. Okay. Parts are mandated. Parts are, if you install something, it must deliver x liters a second. Right? So even the wording is, is weaker than it really needs to be. What is really weak though for residential building is that fresh air supply, and we are still at a stage where the code talks about the fact that, uh, fresh air can come via your windows.
And we all know that windows are problematic for a number of reasons. We open them, we don't know how much airflow we get through, so it's uncontrolled. If it's cold and it's a really windy day, we get lots of air. We pay a, an energy penalty. On top of that, now we've got security. We're building inner city particularly.
We've got security issues, we've got noise issues, we've got pollution issues, dust issues. There's just so many reasons why relying solely on operable windows as a [00:07:00] ventilation solution for fresh air. Yeah,
Matt: be reliable. And it's like no one knows what the air exchange is outside. You're relying on the clients to open the windows and doors.
What if they don't do it? Yep. If it's, if it's 40 degrees or 35 degrees outside, like yesterday, no one's opening their windows because you're running the air con and then you've got the, if it's freezing outside, it's five degrees. You're heating the whole house. You don't want that draft through. Like it was like when you were younger, mom and dad were like, shut the door.
You're letting the draft through. And all of a sudden now we want to open the windows to allow that draft through. That makes no fucking sense. Oh,
Joel: you're letting the heat out,
Matt: sunny. Get that door closed. Yeah. Yeah. So what you are trying to do is allow this really tight envelope. Essentially we want to take back control of the house.
And that's why it's called controlled ventilation. And introduce a system that is going to extract the air out and then replace it with fresh air. Yep. But I'll kind of, before we get too far across the HIV and as a supply side, is when we are, when we are having you, you're probably gonna get asked a question a lot, and I know you've been asked this a lot, is at what point do you need mechanical ventilation?
Hamish: Yeah. Okay, so [00:08:00] how many air changes? How many air changes? What is the magical number? It's my most hated question ever.
Joel: There isn't logically a tipping point where on one side it's like it's a waste of money on the other side. It's awesome. So that, that's a bit of a fallacy, that logic. What I would say is mechanical ventilation is important across all buildings.
Now, if it's a really leaky building, so we're out 10 air changes, plus, then you're not gonna get a lot of benefit from the heat recovery side. You should definitely still have mechanical extract from bathrooms and, and other wet areas. Do what everyone knows. Correct? Yep. That's what everyone knows. And uh, and you can start thinking about, uh, entry level products that just give you some continuous fresh air flow.
To habitable spaces just for air quality. But at that stage, peak recovery is not doing much for you. There's
Matt: a proof of concept. People understand that. They understand if you have a shower and you don't extract that water or moisture from the beam, you get mold. So people understand this. [00:09:00] It's just now we wanna talk about the whole house
Joel: and, and the fresh air delivery, and that's.
It's one of those things, it's, it's, uh, it's like eating too much fatty food. It, it's not gonna hurt you in day one, day two, day three or day four, but over the duration you spend in your house, that that's gonna be a real problem for your health. I, I really, I really like that analogy.
Hamish: I hadn't actually thought about that.
When we talk about air changes too, and, and correct me if I'm wrong when I say this, we might test a house and it might be five air changes, right? But the blower door, which is how we test our homes. Is testing the whole house. Now it is. Then it's the sum of all the leaks. Some of the rooms like bathrooms where you've got lots of waterproofing and tiles generally.
Mm-hmm. It's probably gonna be more airtight. Yep. Than other rooms Now, and you might have a huge amount of leaks underneath the front door. Right. That's where you might be getting a huge amount of leaks through the windows and stuff like that. So even if you are picking a number, say it's five. Your [00:10:00] bathrooms in those wet areas where you are generating a lot of this, uh, high humidity and condensation is probably in an area that is probably more airtight and has less chance of that air escaping.
So I understand now, and correct me if I'm wrong, why it's really difficult to land on Anu.
Joel: Yeah. And the other point to that, Hamish, is that it's, it's also trapping those moisture and odors there, but it's also when you turn just that bathroom exhaust fan on it is saying, Hey, it's highly unlikely the makeup air is gonna flow from the bathroom.
Yeah. It's gonna potentially come from some other shitty location that's got. Air quality issues. How do you roof space from the garage? Yeah. So got your house
Matt: insulation that you've got possum piss and rat piss and rat pool and, and all. And then all of a sudden there's those glass fibers from the old school insulation that you're breathing that in.
Like, correct. Come on guys. It's an
Joel: unknown source.
Hamish: I mean, and I've got like a in, in very simple terms, why? [00:11:00] Do we need to extract and why do we need to supply, I mean, I know we know the answer to that. Yeah. In really simple terms, why do we need to do that?
Joel: Yeah. So we, we extract, the logic always is that we extract as close to the source to remove contaminants.
And in contaminant we can be pretty broad and say, look, that's moisture as a contaminant, but it's also odor, it's VOCs, uh, its particulate matter. So, um, for example, in your kitchen, it's particulate matter when you fry and so you explain what particulate matter is. Yeah. So really fine particles, we're talking kind of non-visible size stuff that stays airborne.
It is in the really small, around the PM 2.5 si size. It is. Which is the technical term is fucking small. Very, I think it's very, very small. Very fucking small. Okay. Yep. Particles of that size are small enough to pass through your respiratory system, and so they're the ones that cause health issues. When they're larger than that, they get trapped in nasal hair and [00:12:00] things like that.
Um, but that small stuff is, is dangerous. There's not established, uh. Uh, acceptable exposure to it. Yeah. That's really one of those things that the science are still developing on, but really the, uh, the, the current status is avoid wherever possible, right? So there's no safe levels. There's no safe levels that, um, are, are documented with decent research.
So a
Hamish: poorly ventilated house is making us sick. Potentially,
Joel: yeah. Quite, quite, yes you can essentially, I could say yes, but we would need to, um, make some assumptions that are probably pretty good. But so
Hamish: on that, in my opinion is, yeah, so personal opinion. There is a totally ventilated house is making,
Matt: so where I live, Maryland City Council, great cancer, really great people there.
They've done a study and in Ong city council. Yes, it is a very like, multicultural area and, and different, um, uh. [00:13:00] Socioeconomic sort of status of different people, but there is a increased. Uh, compared to everyone in municipality, they have an increase in respiratory issues. Mm-hmm. Okay. Now there is issues around refineries, uh, fumes from the cars.
Uh, there is the, um, transport there through all the, the shipping yards in that area. Um. Refineries, all that sort of stuff. Now they've been on a show that like, yes, it could potentially be linked to, or maybe a lack of education on certain things, Uhhuh, but there is respiratory issues and that that's, that is wildly documented.
There are other studies, I know there's a study at the moment that's happening with a school in Yarraville where they've, kids are walking with these DYS and backpacks to understand the air quality and it has gone through the roof. And the reason I know this is 'cause my bookkeeper's son has been in it and she sort of passed me on some of the data.
And so these are known, these studies are getting done. They're kind of getting hidden though. And the governments aren't doing enough. It's been in the media recently around the foot, around the yarraville with this new tunnel they're building is they've got the ventilation stacks and they're saying they can't [00:14:00] really, oh, we can't fall to the air.
It's been like, it's just other countries are doing it, they're doing in Korea. We're just not doing it
Joel: for an okay price is what they're not saying in that sentence. We, we, we can't tackle this at an acceptable price in our view. So I've actually written down here,
Matt: I mean it, I think it kind of leads in well, is that like.
We, we talk about the upfront cost, and everyone talks about the building cost. So what is the cost on our healthcare system? Yeah. And that's poorly documented. We don't wanna know and what's the value on someone's human life? Yep.
Joel: Now I know the Asthma Association have got good numbers on that. I don't recall 'em off the top of my head, but for Australia I believe it's in the billions.
So, um, that's billions. Yeah. The Passive House Association is working with, um, as a billions and billions customer association and they're well across what those savings are. So absolutely there are. Unmeasured health benefits, unquantified health benefits, are they
Matt: doing enough to push this or they kind of get pushed to the side or quietened down a little bit?
The association or the asthma? [00:15:00]
Joel: Both. Both. I, I, I think so. I, I, I think it's always a challenging, um, role to a, going hard enough to get meaningful. Uh, is without putting people offside to the point they don't want to deal with in a constructive way.
Hamish: And I think it's important not to sort of big note, the conversation we're having now is that we obviously have an audience that this is going out to, you know, and we're hoping to educate more people about the importance of ventilation.
So I think the more of conversations like this that happens, the more people start listening. Absolutely. Because if there's just. I was about to say, just the Asthma Foundation. They're a big, pretty significant organization. Um, but if it's them and then afa, and then it's the builders and then it's homeowners, and everyone's like, hang on a minute, what about our internal air environment?
What are we doing about it? Then maybe the A B, CB might listen up and
Matt: kinda listen up. They're funded by the p the people that are on their boards that are going to [00:16:00] actually. They're coming, they, they, they, they really don't care. They move at the slowest person's pace, the low and con lowest common denominator.
Hamish: Look, I think, and I've said this before actually, um, on various different bits of media, and I've circled this here, like we actually have a choice that we can build above what the nccs absolutely telling us to do. So,
Matt: but this is the issue. The people that we bill for have money. The people that are at most risk are the people that don't have the money to be able to put these things in.
They're the ones that are generally lower socio socioeconomic. They're the ones that, uh, don't have the money to go to healthcare. They're the ones that, they're the ones that have the issue. I
Hamish: think this is the point I was trying to make before, though, like, yes, you are talking about Zen. It's a premium product, but I think this is, this is news to, you know, really good news to me when I hear there's other products coming out.
Yeah. Which are gonna be of a lower cost. Yes. They might not be as efficient with the heat recovery. Yes, they might cost a little bit more to, to, to operate, but it's still a positive thing and I think the [00:17:00] more. People start asking for this stuff, the more people start listening from a supplier and import and manufacturer point of view.
So we're gonna get more products in the market there and then maybe there's end price will come down.
Joel: And there's also an education piece there as well pitched at lower socioeconomic groups. 'cause that's usually the other bit that's missing, apart from not having the cash, it's not having the knowledge in that space education.
But we've always done this
Matt: way. We've built houses for 50 years and it's never been a problem.
Joel: That's a great statement, isn't it? Until you go to, uh, pull the cladding, peel back the cladding, or, uh, talk to the owners or the tenants. So,
Matt: and when you, when you peel it back and you get, like, on the bottom plate, you just see that little thick layer of sort, like, it's like an inch high.
Hamish: I'm gonna, I'm gonna paint a picture, um, Joel, and this obviously hypothetical. So Matt and I build a house to identical house side by side. I choose to ventilate my house correctly. Matt chooses not to, not to ventilate the house correctly. We are both building the same one 40 Starge, good [00:18:00] insulation intel external, um, air tightness barrier.
Really great windows identical except for the, um, ventilation system. Tell me a story about how Matt's house is gonna perform over a period of time and tell me how this other house is gonna
Joel: perform. Yeah. Okay. So, straight away from a durability perspective, what you've done in building this nice, um, airtight box with insulation is you've set up potentially some condensation risk.
And so without, for both homes, actually. For both homes, yep. Yeah, good point. So, identical, I'm assuming identical structure Exactly. What the ventilation, the mechanical ventilation is doing is making sure that moisture has a path out of the building. Yeah. So either, whether it become through the wall or roof assemblies, or whether it be internally generated, there's a path out of the building.
So that's the first point. You've got durability there. Uh, now we get onto thinking about occupant, uh, health and comfort. So without that ventilation, it's gonna [00:19:00] get pretty nasty. From a stuffiness perspective, so occupants. Are gonna go to a window, like there's really not much choice if you are doing that, or are they though you sell a thing they don't know?
Possibly not. I, I, I think mostly if, if you had zero extraction inside your house, it's gonna be so humid and nasty in there. You open up a window, you're gonna crack open a window. Is that gonna solve your problem? That's the real question. Maybe some of the time maybe it creates those security risks. The other part obviously is air quality, and that is, um, basically saying, look, without ventilation you get, uh, accumulation of contaminants.
You get VOCs outta your carpets and bench tops. You get CO2 from respiration, moisture. Uh, you get CO2 from any gas, cooking and other particulates in there. So, and burning eggs. Correct. And burning eggs is Cameron Monroe. So, uh, everyone loves a good fry up at least once in their lifetime, don't they?
Matt: So this is probably a good question.
And so now we're [00:20:00] talking about cultural differences. So some cultures will fry their food in a wok and burn things off where Yep. Some. And maybe more of a steam or boil or, yep. So then, then again, we're having a whole different conversation that they, it comes down to again, that Dan AirBoss, Dan spoken about in Germany, and people will open up their windows just as a cultural thing.
Yeah. Where here we think we open up, but do we actually do it?
Joel: Yeah. Correct. Correct. I, I think the number of window opening activities is super low. Um, the passive house institute's got some good studies on, um, how many windows and how long you'd need them open for during a day. It, it's not just open for 20 minutes at the start of the day to purge the air from your house.
You need them open every three or four hours, uh, in order to maintain that air quality. So, so going back to that
Hamish: example we talking about before, over a period of time. Uh, in the house that is properly ventilated in the house that is not properly ventilated, what are we likely to see in the bathrooms? In
Joel: the bathrooms?
Yeah. So you can just [00:21:00] start to see moisture that can't get away. So you are gonna start to see the evidence of mold growth, that those sorts of things are animal and malts bad, right? Just
Hamish: wipe it off though. If you're doing a quick reno, quick and flick. Yeah. You could wipe it off. So it, Matt and I are probably being quite facetious.
We know the are here, but really, um, I think it's good to paint the picture of like why it's important and, you know, there's a huge amount of studies on the impact that mold has on particularly in children. Mm-hmm. Uh, and how bad that is, particularly in-growing developing bodies. Yep. So, you know, you have a house that.
Is not managing its, uh, moisture and used air correctly. Increase in mold, high humidity. Yeah. Um, and then so there's the occupant health, but then there's obviously the, the structure health as well,
Joel: correct? Yep. So that mold could be surface born where maybe if you like Matty, you can get a sponge to it and clear it away.
White king, and off you go. Yeah. White king. [00:22:00] Yep. Could also be in the structure. So every time you turn a bathroom exhaust fan and it sucks a bit of air through that structure, those mold spores are coming back into your bathroom. Yeah. Yep. And into your life. So I think,
Hamish: you know, just that alone probably paints a picture of one, how you can think you, you can think you're doing the right thing by making an airtight and really well insulated structure.
And, and I, I guess this is why, you know, passive house is so prescriptive of what they're asking you to do. You know, ventilation is a massive component in the health of our buildings.
Joel: Absolutely. Absolutely. The Europeans seems to be way more science driven, so they're making code decisions based on hard science versus, and that's a number approaches.
It is. So,
Matt: so with science, science is an interesting thing. Just we talk about covid and do, is science become this woo woo thing? Has there been this movement against it?
Joel: Yeah, I think so. I think, um, the Trumps of the world, COVID saw some pretty bad examples of, [00:23:00] um, politics trying to trump science. Pardon?
Pardon? That's it. Pardon? Pardon.
Matt: So now when we talk about getting more airtight, um, we're, we're talking about the H-I-V-E-R-V heat recovery ventilation, which it becomes a little bit more important with what, how Hamish and I would build. Do you wanna give an explanation of what HR v's ERV, where this imaginary line of where you're gonna need them
Joel: taking half a step back?
HRV and ERV. What are they? So, HRV uh, really talks about, uh, sensible heat recovery and. To put that in, probably easier to understand terms. That means temperature related heat recovery. So let's say going from 10 degrees to 20 degrees. If we transfer just heat and we get that, um, outcome, that's called sensible heat recovery.
If we talk about ERV or inpe type, uh, heat exchanges as well as transferring that, uh, sensible or that thermal energy, we also transfer [00:24:00] moisture. And so, so what was that word? En enthalpy. Enthalpy could have come with an easier word. Yeah.
Hamish: Unfortunately. I'm gonna forget that. Heap's Much
Matt: easy to remember. I thought it was energy, energy recovery, ventilation for so long energy.
Joel: And then I was like, nah, it's the E one. So there is energy as well. It's a really confusing landscape and a lot of people will use them interchangeably. So we often need to pause and say, what are you really, what's your climate? What are you really looking forward
Matt: to? And that's why I say that imaginary line, we're talking here in Australia, if you haven't picked up on the accent.
Um, maybe just above Sydney. Or it's a bit more humid.
Joel: So E-R-V-H-H-R-V has got the better temperature recovery, uh, full stop. Where we need to think about is, uh, moisture. So taking half a step back, if we say comfort isn't just a function of temperature, it's a function of temperature and humidity. So we can have the temperature bang on, but if the humidity's well out of our bounds.
Yeah. What's a
Hamish: good
Joel: humidity ban band? Yeah. So 40 to 60% is probably [00:25:00] for relative humidity. Is, um, nice and temperature wise, if you're in that 20 to 25 degree slot, um, there's plenty of literature that talks about comfort bands within those ranges. Uh, and so where we start to think about ERV or PY cause is can we manage the moisture side a little bit better?
Now, the moisture side can mean either, um, we've got excess moisture or a bit dry. And so the cases where we might have excess moisture arise from high outdoor air, uh, humidity. And so that's where we're
Matt: starting. That's a pressure. It's pressure moving in. Is that right? So pressure goes from high to low.
Am I right here?
Joel: So there's, there's a moisture transfer gradient. I, yeah. Pressure's perhaps not quite the right word, right word, but we know in Queensland summers we've got really high moisture content in the air and un uncomfortably high if we. [00:26:00] Just brought that in through A HRV type core, we might get the temperature in the right zone, but we've got moisture too high.
And so in that warm, humid, outdoor air conditions, what ERV allows us to do is to bring the temperature down and also bring the moisture down. The other application, which is rarer in Australia, but more common in Europe, is for really cold, dry, basically alpine climates. I was
Hamish: about to say that 'cause Cam Cam mentioned that, uh, and this was new to me, that.
Say in net, man, Hoffer. You are probably gonna want to put an ERV in.
Joel: Yeah, so there you've got the reverse problem. In winter, because the temperatures are so low and there's ice, you've got very little free moisture in the air. And so by the time that goes through your heat recovery unit. It's turned into supply air.
Your temperatures might be under control, but you might be at a relative humidity of 30%.
Hamish: Wow. Okay. And then, and if it were a really low humidity, what is the occupants experiencing inside?
Joel: Yeah, so it's, it's [00:27:00] dryness. So it's got like standing in front of a. Pedestal fan for an hour, you can sort of barely talk and your lips are stuck
Matt: together.
Yeah, right. When you're in Asia and you put the aircon overnight and you wake up and you're like,
Joel: that is exactly the problem. That is exactly, because we find aircon will remove moisture, but for humid environments like Queensland. When it removes the moisture to get the humidity right, the room's now at about 15 degrees, right?
Like that ratio of moisture removal and temperature control is wrong.
Matt: So when you have an ERV, are you also suggesting they'll put a humidifier in the house too?
Joel: Not a humidifier. So that application where we need to boost indoor humidity is really only alpine regions. Okay. So that's such a small part of it of.
Construction and particularly sort of passive house that, um, maybe there's an application, but the more common one is, do I need a dehumidifier in that Queensland, uh, project as well, and both filter out the air. No. So [00:28:00] the only thing bringing outside air into your air type box should be your, uh, mechanical ventilation system.
Yeah. Everything else should be just doing a rec circ. So, and you're heating and cooling, that's just drawing, airing from one part of the house, conditioning it and spitting it back. Same with the dehumidifier. It's taking indoor air and stripping the moisture out. Provide amp back into the house
Matt: and HIV or mechanical ventilation, just to be quite clear, is in a heating and cooling source.
Joel: Correct. As the name sounds recovery, there needs to be a differential. So, uh, if you, for example, locked up your house in summer, left all the blinds up and no shading, and it got to 30 degrees when you returned home and the outdoor temps were 30 degrees, your HRV is gonna do nothing before you. There's no differential recover, and that's where you need that ancillary air conditioning to get the temps down in the first instance.[00:29:00]
And then the HIV will help you hold those temps.
Matt: And I know the answer to this. You can't just plug your. Heating cooling system into your HIV distributor, it doesn't work like that.
Joel: Correct. The airflows are substantially different. The, um, you would need to be oversized two to three times even in a passive house.
Yeah. Okay. Type building to deliver enough heating or cooling capacity. And people tried it. Yeah, we've tried it. So fan tech's done half a dozen, uh, systems like that using some bulkhead AC units. What we found was that the, the cost complexity and the resulting capacity just wasn't enough to justify petting down that pathway versus multiple split.
There were even advanced iterations that had a recer loop into the ac. They fundamentally. Were too complex, requiring too much space. It became difficult solutions and split system AC units are so cheap. Didn't make sense.
Hamish: Now I wanna go back [00:30:00] to a comment you made before about VOCs and you know, we're obviously talking about occupant health and a lot of things off gas.
Mm-hmm. Carpet, joinery, uh, paint. Mm-hmm. Does the HRV help extract. That off-gassing.
Joel: Yeah. So the best way to think about ventilation is it's a dilution strategy for contaminants. So we are not, uh, physically like an air purifier trying to filter out or trap those things. What we're doing is ensuring there's enough air change in the building that we dilute, keep those diluted.
Yep. Yeah. In industry speak, it's known as a dilution strategy. Yeah.
Hamish: So how often does the air change? In home with a good ventilation system. So let's use the gender. Mm-hmm. Q3 50 as an example. How often does the volume of air in that home change?
Joel: Yeah. Okay. So around the option [00:31:00] 0.3, uh, to 0.4, air changes per hour.
Hmm. And the reason for that is, uh, going higher than that risks that case we talked about earlier of excessive dehumidification. Ah, okay. You can drop the relative if you are 0.6, 0.7. And we saw a lot of conversations around Covid times saying, look, they're just way too large, uh, too low. We've gotta blast lots of air through this building, okay.
In order to save us from Covid. The, the real issue there is. Relative humidity control. Yep. And,
Hamish: and something that Matt touched on before, like on average the, the Australian home changes its air inside about 17 times. Right. And you know, you saying now that the ventilation system done need doing that, you know, 0.3 times, uh, an hour.
Yep. Whereas a normal home is 17. Why don't we just build homes as we've been building homes?
Joel: Yeah. So it's about the quality of that air. There's no point having huge [00:32:00] amounts if it's unfiltered and we don't know the source of it. Uh, and it's also unreliable. That's 17, probably under a 25 kilometer an hour wind on a still day.
It drops to two. Yeah. Or half or,
Hamish: and. Correct me if I'm wrong. Going back to a point I was talking about before, about certain rooms being more airtight than others, given that, you know, our ventilator systems are a balanced system and there's extract and, and and, um, fresh air in strategic place throughout the house.
So it's a balanced system, whereas in a home it is leaking 17. Air change in an hour, those 17 air changes might be coming outta one room,
Joel: correct? Yep. It, um, is uncontrollable in terms of, is that bathroom actually getting air drawn out of it or is the bathroom and the toilet odor being pushed back through the rest of the house?
'cause the, because of the wind direction, the suctions on the bedroom side of the building. So we're, we've gotten, we're not doing that, um, point. [00:33:00] Uh, extract for contaminants where know, you're kind of just mixing it all up like a mud pine, hoping it'd escapes somewhere.
Hamish: Um,
Joel: so we're making our buildings
Hamish: airtight.
What happened if the power goes out?
Joel: Yeah. Are we all gonna suffocate?
Hamish: No. You die.
Joel: That's a question. We die. Yeah. So you've seen all the news articles and the current affair recently of people going down HRV went out. Yep.
Hamish: Uh. That was sarcasm, by the way.
Matt: Yeah. I love a current affair. I think it's like the comedy channel.
It is one of, seriously, one of my favorite shows to watch. Like it is just absolute choose on because
Hamish: we like watching a car crash back it. It
Matt: is seriously so funny.
Joel: I have to bring you back to ventilation from a current affair. So my best analogy for that is that we are unwittingly already building really airtight buildings without ventilation.
And that case is precast concrete, uh, apartments. So some of those without any attempt to build air tightness into them, some of those buildings are getting to two air changes and below, and we're not seeing people pass [00:34:00] out. Uh, and we're not seeing people die in those scenarios. So yes, the air quality's really poor, uh, and so they would absolutely be recommended to keep their windows open.
Doesn't really. Make the air quality nice and all comfort, but uh, just giving us the means to survive. Correct. Yeah. So, and the same for really air type building. Open your windows for the short period, your powers out. Once the power comes back, the units will start up. They'll remembered all their settings, so there's no, and
Matt: you can still open your windows and doors on a nice day.
It's, you highly
Joel: control, you have the choice. Correct that, and that is what it's about, isn't it? Yeah.
Matt: So I want to, I've just. Got my phone here and I wanna make people aware. Now, in the NCC, the Moment National Construction Code, there is a clause that says that, that we must not exceed a mold index of three.
Otherwise, as builders, architects, whether we're liable. Yep. Can you explain what that means? Because what you have essentially is a system [00:35:00] that will prevent it. If installed correctly. Um, and I think this is something that our industry needs to understand because we're now at risk. Yeah.
Hamish: Can I also add to that, that there's no mandatory provisions to ventilate your home properly in the N ccc that would mitigate Yeah.
So there,
Matt: so you've asked to do something, but there's no guidance on how to do something, but you're liable. Yeah. And lo amount today may bank on this.
Joel: Yep. Yep, yep. So my understanding of the mold index, um. Um, terminology there is, it's, it's a risk profile. So we are looking at what the chances of our building, developing mold are.
Uh, clearly not having ventilation in there, um, is, is problematic and it, it's certainly a, a, a necessary backstop to make sure that value, uh, is, doesn't result in actual mo growth. Yeah.
Matt: Is, is there a lack of adoption in this because people just don't understand how to talk about it? [00:36:00]
Joel: Uh, it, it's a tricky one.
So lack of adoption at a. Building codes board, is that what you're,
Matt: no. Yeah. And yeah. Well, for building codes board, but to an architect or building designer to a builder, like there's multiple stages that can get stripped out because budget's always a thing and not everyone has a money tree. So from an NCC minimum standard, we don't need it.
Which excludes probably the whole volume spec industry because why would I put it in? Yeah. Don't have to. Architects and actively the ones we're working with really wanna put it in. Yeah. But there's always this issue. Now when we talk about, uh. Essentially, like that's still the cost issue. So it's one of the first things that attempt to be stripped out by, by someone.
Not the a, not just the architect. It could be the client. Yep. Um, it could be a builder. So then you're trying to get that out. So is it just a, how, how do we then get a wider adoption?
Joel: The ventilation? Yeah. So I, I can absolutely see the temptation. It's not mandated in the code. So you can pull it out without any risk to compliance.
You can't suddenly reduce your electrical [00:37:00] cabling size to save money. 'cause that's code driven and standard driven. You write it to the education piece. So through those layers from architect or builder to end client, it's about communicating what does, uh, making this change. How does that impact your building and, and.
That conversation is very disjointed, non-existent at times. Uh, I think it's also a function of are you actually building for the end occupant? Now, fortunately in resi, most of the time we are, but you start getting to apartment buildings or uh, commercial buildings and there's no longer that connection.
There's no longer that person who's gonna be in that building. Driving that specification.
Matt: Well, didn't recently, the other day. Didn't the, uh, VBAO, her and Victoria changing a law around class two buildings, that there must be a bond held against the developer or builder for two years to, to warrant the defects.
Now I think we see be huge issue [00:38:00] with, with mold and with air tight homes 'cause it, it will. Be shown up within two years. It's not, this is something that's gonna happen very quickly.
Joel: I, I reckon it's great. And you hear way too many current affair stories, Matt, particularly in apartments and even class one homes for where they're trapped between a builder who's not done the right thing and, and the builder could have done the right thing.
It's not speced. Yeah. Yep. Or the builder's done the wrong thing and the recourse measures are just really weak without being the risk of
Hamish: not being too clickbait. Um, this stuff is not complicated. And I think that, you know, if you think about some things that people may not adopt is because maybe they don't understand it.
Joel: Mm-hmm.
Hamish: I completely understand the benefit of good ventilation, and I would say that I would, I'm a normal person, and when explained really simply, you know, you can put two and two together quite easily. So. You know, let's not poo developers, not poo who the NCCI think we can poo the NC. What I would like to [00:39:00] say right now on the record is that as a builder or a homeowner or a designer like this stuff is not complicated to, to implement into your, into your buildings.
It's not you. You're not having to change the way that you design and build homes. Mm-hmm. It's quite a simple thing to add in. Yeah. You are not restricted by what you can design. You're not restricted or how big or small the home can be or how it looks. It's the size of a washing
Matt: machine that can go in the laundry like every other job
Hamish: there are, you know, we have, we've predominantly been talking about centralized systems, but there are other options.
There's decentralized systems as well. Yeah. So like this stuff, I guess the point I'm trying to make is it's not rocket science.
Joel: It's not, I, I think I'm, uh, probably sitting with a couple of the bleeding edge builders and so I'll, I'll kind of be nice to builders in general and say. There are a lot of elements to building a building, and some of those might be regulatory planning permits, uh, dealing with owners who are changing their mind midway through.
So I do think the building process as an entirety [00:40:00] has got a shitload of moving parts.
Matt: Yep. But is there an issue that I, you can be categorized from the three people. One that you just don't care and you don't do anything about it, you don't know. Cool. I can live with you because at least you don't know.
Then you've got the people who are actively doing something and understood it and changed the people that I hate, the people that have gone through the effort to understand it, that know what happens when it doesn't go right. And the the benefits, these things, like what happens with them and then don't do anything about it.
Yeah. They're the worst people because they actually understand it and then they just choose actively not to do something about it.
Joel: Yeah. Yeah, and, and I think they struggle. With communicating to their clients why it should be done that way. I think that's the real weakness.
Matt: That's what I go back to when we talk about adoption.
People just don't know how to talk about it, and it's very simple. Do you like clean air? Yeah, I like breathing clean air, but one in,
Joel: we see that all the time with, uh, younger builders in the. Come through, have done the passive house straining course or something equivalent, uh, and are struggling to pick [00:41:00] up their first passive house project, and it's because they are struggling with that communication.
Yep. This is what I want to build for you, and this is what it'll deliver. This is probably a really great
Hamish: spot to finish on if you were stuck in an elevator for a couple of minutes with that young builder who was really struggling to communicate that last piece. Yeah. To a homeowner. What advice would you give
Joel: them?
Would you, would you say so get on board and start building that way as quickly as possible? It, it's the way everyone will be building in not too distant future. So you're only putting off the inevitable. Also, get into a space that you can get passionate about. And, and, and enjoy and, and go to go to bed at night saying, I'm building something better than average for my customer.
Like there is so many upsides. Think of it also as de-risking your project ventilation in your project reduces those moisture related issues. So you, so you're [00:42:00] de-risking it, it will drive you through tighter documentation, which can, seems tedious and does add a little cost layer, but it. Again, as a builder, it just provides you certainty and risk protection.
So don't shy away from expanding your knowledge and taking on something of just a bit larger than what you've previously done. It, it is the way everyone will be doing it, and not only that,
Hamish: the support and the information and people like yourself, Matt, myself, drew all these people out here now who have done it, they've gone through it, you know, they understand it.
It's a standard in our buildings now. It's easy. The answers are there. The answers are there, and the advice is there to be given. Now we had to figure it out. Yeah, I remember the, some of the first times I'm talking to you going, what the fuck is this ventilation
Joel: business? Yep. There's some great organizations, SBA, Hasif House Association, and all those people in those kind of groups are really willing to share information as you guys.
No, you are [00:43:00] often the sharers of that information, so sharing is caring.
Matt: Um, Joel, thank you very much. We've just from not just coming on today, but also the help that you've provided for both of us over the last probably five, six years, you've helped our businesses get to where they are. Um, without you, we can't build the homes that we do.
Joel: So thank you. Thank you mate. And it's very much been a mutual partnership. So we're, uh, symbiotic as I like to say, well, parasitic one or the other.