Zehnder ERV, home ventilation, indoor air quality, maintenance

ERV’s – Explaining the health and comfort benefits of installing an Energy Recovery Ventilator in your house – 2 Years later Review

Foreword by Ian Thompson, Editor

Scenario: You’re overseeing the design of a new house, office building or educational space. The client has asked for optimal indoor air quality and maximum energy efficiency – what’s the potential solution? Enter the Energy Recovery Ventilator, or ERV for short.

An ERV acts as the lungs of a building, constantly exchanging stale indoor air with fresh outdoor air. But, it doesn’t stop there. The ERV cleverly transfers heat and moisture between the incoming and outgoing airstreams. This means even in the depths of winter or the peak of summer, the building’s internal temperature remains stable while still introducing fresh air.

So, what are the benefits for your building project? Firstly, indoor air quality will be significantly improved. The ERV reduces the presence of pollutants and allergens and keeps odors at bay. This makes for a healthier and more comfortable environment for building occupants.

Secondly, the ERV’s heat and moisture transfer capability enhances the building’s energy efficiency. It reduces the load on heating or cooling systems, leading to less energy consumption and potential savings on energy bills. This is a huge selling point in today’s eco-conscious market.

Additionally, an ERV provides effective humidity control. For buildings located in regions with extreme climates, maintaining optimal indoor humidity levels can be a challenge. The ERV addresses this by transferring moisture along with heat.

While ERVs might require a higher initial investment compared to traditional ventilation systems, they could lead to significant long-term savings and improved occupant satisfaction.

In a nutshell, if you’re aiming for a building design that promotes health, comfort, and energy efficiency, an ERV could be an excellent feature to consider.

Over to Matt and his personal experience 2 years after installing an ERV in his new house.

Matt’s ERV – Energy Recovery Ventilator – 2 Years Later

Video Transcript

Hey friends, welcome back to my house. You watched any of this house being built? I call this the real rebuild Series. This is my family’s personal home that I finished about two years ago. And on this video, we’re going to spend some time with that piece of equipment right there. That’s a Zehnder ERV, basically a fresh air system, the lungs for my house.

It’s been two years, and on this video we’re going to show you the normal maintenance and the maintenance you want to do at the 2-year mark. We’re also going to spend a little bit of time talking about ERVs and Lessons Learned.

This is my first house I’ve ever lived with one, and I’ve learned a couple of things. It’s been awesome, but there’s been some surprises along the way that I didn’t quite expect. So we’re going to spend some time getting into some really nerdy details today. Today’s build show all about Zehnder maintenance and Lessons Learned, let’s get going.

All right friends, nerdy video hang on. We got a lot to talk about. We’re up in my attic. I’ve been here now 2 years, so my Zehnder’s been running for two years. We’re going to show you some annual maintenance, and I’ve got two really smart friends with me.

We’re going to talk a little bit about how my unit has worked, some surprises after having a well-ventilated house. I’ve never lived in a house with an ERV before. So let me introduce uh, you probably met Sean Harris before. In fact, Sean is the guy who helped me realize at my old house that I needed to rip everything out.

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We showed uh, a lot of rats running around in my old attic before we rebuilt it. And Szabi is uh, Szabi, you’re kind of the lead tech guy, sales guy at Zehnder, right? You – well you do a little bit of everything.

Yes, correct. I’m sales and tech support, sales and tech support. So two years ago we installed, or two years ago I moved in, I should say. Uh, Szabi, I’ve done a pretty good job of uh, maintaining this unit, but I’m hoping you could walk these guys through what’s it look like to maintain your unit? And as we’re talking about that scheduled maintenance, I want to uh add a little killer commentary, right?

Because manufacturers, every manufacturer, Sean, has recommendations, but as you know, and as you guys are going to find out, recommendations are that they’re not necessarily what’s happening in your house with your number of children, with your dogs, whatever it is in your climate. So I think that we’re going to learn a few things.

So Szabi, first off, what’s the first thing you need to do on a maintenance uh for a unit like this? So the you have LAN-C connected to your unit, that means that you have option for internet. So what I’m recommending for everybody to do on the unit before you touch anything, just take a look on the unit, do you see any noise, weird noise, weird signs, dripping water, any problems?

If you don’t have any major issues, then we start approaching the unit and take a look what’s happening, what we can do. The system was built very easily and the simple maintain, we opening the front visor and we have the two filter slot openings here which is technically the major maintenance for any homeowner.

You take out the filters, and so you’ve got one filter which is filtering incoming air and one filter that’s filtering the exhaust air out of the house, correct?

So you can see on this unit that this side of the unit, we call it the outside side. These are the two pipes which is pulling the air into the house and pumping the air out from the house, yep. And these two pipes going towards your house and coming back from the house, so they are Supply and extract, yep. Got it.

So the filters are different, we have two type of filter on our units. A MERV13 filter, easily identifiable because it’s a red color, yep, and notes on the end of the filter. And MERV 8 filter, which is black. Now why do you need a filter on the exhaust side? I bet people are wondering what difference does it make, we’re just throwing that air outside, what’s the purpose of that exhaust filter?

So the exhaust filter is protecting the core. Always keep in mind the heart of this unit is the heat exchanger core, which is behind this front, which we’re going to show you in a minute which will show how it looks and what it needs to be done for maintenance on that.

That core is the heart of this unit, and the two fans here and here. So when you’re cooking, you taking a shower, you using hairspray, not you, but your wife or your kids, it’s possible that chemicals can come back towards the unit, and we want to capture those particles with this filter because again, and we want to protect the core. Got it.

So let’s show how dirty those are, and I want to keep in mind uh, that the manufacturers, like if you’re just looking at the the specs, remember this is a Swiss unit, they originated in Europe, they say that we should change this filter after a half a year, 180 days.

I learned pretty quickly on that I need to change it more quickly or sooner than that. And that filter, has been in for around 100 days. I actually have a note in my phone to change it at 90 days, which is half the recommended time. Sean, what’s your opinion on why that thing’s so dirty?

Yeah, Matt, so you live pretty close to a highway, and uh, there’s a lot of brake dust that gets generated, diesel fuels, all sorts of things that are happening with air quality next to a highway that you really want to be filtering that out. You want this filter to do it, not your lungs to do it. So being able to have this filter do that is great, but obviously you’re going to have to need to change your filter more often than someone who lives out in the country, who may get a lot of dust or something out there as opposed to to here.

So and look at that differ, Szabi, holy cow. So this, that’s what I just pulled it out. This is 100 days in use, and that’s what the brand new, Sparkling White filter looks like. And I think Sean’s right in the money. You know, I’m not that far from a big highway. I’m in the city, I’m like 10 miles from downtown Austin, Texas.

You know, I’ve got all the big city pollutants going on in the air. And you know, I lived across the street for 15 years without an ERV in a pretty leaky house, a uh, four or five ACH50 blower door on that house across street that you did for me years ago. This house very tight, almost passive house standards.

I’m pretty close to .6 ACH50. So this is the lungs, and in my old house, this was happening, this was in the air at my house. And here we’re able to filter that out. That’s for me, this is a big reason why I really like Zehnder. And if you look at some of the competitor ERVs out there to Zehnder, very chintzy filters, not this level of filtration.

Yes, you are correct. So my customers are asking all the time that, “When I know when the filter is dirty?” This is a perfect example. When it’s black, it’s dirty. I think new Zehnder going in, you really need to check it about every 60 days or so and see what’s it looking like. And when I did that, I was shocked. Oh my gosh, look how dirty this is after only two or three months.

Now Szabi, uh, so that filter change comes in a set. You can get a kit of a black and a red, and it’s simply just pull it out, push it back in, it’s really straightforward, correct?

So the set comes with two filters, black and red. And you just pull it out, some of them is in a plastic bag, some of them not. You just take it out from the plastic bag, you take out the old filter, you push in the new filter. The only thing what you have to pay attention, there are arrows here. The arrows has to point up, yep.

So I’m putting the filter in with the arrows up on this side, and on that side is the same thing, the arrows up, yeah. Smart. Now, I put intake filter and exhaust filter labels on there, but you know Szabi, you mentioned to me off camera earlier, I think it’d be really smart for me to put a little uh, red filter and black filter just to make it even more dummy proof.

It’s definitely yes, in lots of cases because people are not necessarily expert knowing what is the exhaust filter or intake filter. And New York, for example, where I work, you don’t even see these pipes because everything is above the rack, just the unit, yep. That’s right. So you don’t know which one is which, certainly.

Okay, so let’s let’s talk about filter changes real quick. Their app is fantastic. It’s really really easy, it connects easily. Okay, so we’re going to hit the uh, Comfo Control app, that’s the app that uh is talking to my Zehnder. And you can see it’s in medium speed right now, let’s go over to filters. So hit this, and then it’s going to walk you through that process: open up those two doors, pull the filters out, uh this filter is the incoming, this filter is the outgoing.

Put the Caps back back on, uh, filter change complete, we’ll hit done, done, and your timer is reset for 100 days. Okay, now my timer’s reset. So that’s what we’re going to be doing, uh, initially every 6 months, but I’ve decided I’m going to do that on about a 3-month basis on my house. And Sai was able to get into the uh, installer settings and actually change my app that’s something you could do with your uh, installer when you’re working on your system, they can change that for you.

Uh, Szabi, at a year mark though, or maybe two year mark, what’s the time frame that we’ actually need to clean the core? So lets me jump back. Changing the scheduler, you don’t need the installer settings, that’s any home owner can do that. Under menu, filters, and here is the filter scheduler. Got it.

So we can actually change it right there up and down from 100 day to 180. So it’s any home owner, you don’t need anybody to do that. So if you’re a homeowner and you know that your filter is getting dirtier than 180 days, you can actually change the schedule and it will give you a warning signal that you should change the filter because I reached 100 rate, 100 days.

Gotcha. So maintenance at Zhender, we recommending large maintenance on the unit. Large maintenance includes take out the core and wash it, clean it in every 2, three years. Two to three years, okay. So not every year? I’m right at the right mark at two years. At the older CA series, it was was definitely 2 years recommendation.

At the new Q, the documentation for the core says 3 years, but if you clean it in 2 years, it’s never going to hurt because when you open up the unit, you will see lots of things inside of the unit depends what is the environment you’re living in. Some people have creatures inside, spiders, insects, dead bugs, right? Vacuum that out, vacuum that out. We will open up the unit so you you guys will see what we’re talking about.

Don’t be scared because this unit is pulling air from outside, and on in this pipe, lots of things can come in and that will end at the filter here. And when you changing the filter, you’re pulling out and you put in the new one, sometimes the bug fell down below the filter so it’s on the top of the core or falls down to the bottom of the unit. It’s just the beast of the nature. It’s perfectly fine. The unit is not hurting by that. We can vacuum it out, clean it out, wipe it out, and put back everything together, and the unit runs again. Got it.

And the core is pretty straightforward. You’re going to take that to a bathtub, uh, you’re going to use this little uh uh, what is this a T20 bit or something? That’s a T30, T30 to pop that off, and the core slides out. We’re going to wash that in the bathtub with water, let it dry out, put it back in. It’s pretty straightforward.

So if you are handy and you have mechanical skills and you are confident that you can do the cleaning for the core, then you can do it yourself. Yeah, however I highly recommend to have trained technicians to do that, HVAC contractor or Zhender agents, because we know what we do. It takes us much less time, uh, but at least we know what we do. So only touch the unit if you’re confident that you can handle it properly. If you’re not, just get help from professionals. Okay.

Now we have a couple other filters to do though, right Szabi? We’re not done here, just at the unit, correct? So Matt, at your house, you guys got a unique installation. As you can see, you have an additional filter box here for additional filter options. And uh, we recommend it at Zhender for California World wildfires, but in this year in New York and up Northeast, we could see the same issues what California dealing every year.

We had four or five days of beautiful orange cloud all around. So additional filter, it’s a great option. And so this filter is giving us additional filtration before it sends to to my house for the supply side, right? Correct. So if let’s take a look at how dirty those are. By the way, if you’re looking through the air flow, it’s coming through the pipe, coming through the MERV 13, get to your fan and your fan is pumping this way towards the house, so your second filter is here.

So let’s take a look, and I’ve got some new on Szabi ready to go for you. I like to keep a stock of uh, at least two years of filters laying around. And this is a little bit more of an expensive filter. And you could vacuum this every 6 months, and in fact, I did vacuum these 6 months ago, but let’s see how dirty they are after the magic box.

They’re tight in there, aren’t they? They are tight because we want to be sure that the air is not going around the filter. That’s right, yeah. Tight is good in this case. Tight is right, as my father-in-law says, which is my favorite uh, funny family line whenever his wife asked him whether this dress is too tight.

So old and there’s new. I did vacuum these six months ago. In fairness, so they’ve been vacuumed once, and my plan was to vacuum them once and then change them at the end of that year. And boy they really need it, look at that, that’s crazy. Szabi, yeah, Just keep in mind that these filters are MERV 15 rated filters, these are capturing really small particles less than 2.5. So even smoke potentially could be captured by these, right? Not the smoke particles, yes, but the smell, not. Got it. So for the smell we can use in the same box, it’s called a carbon filter, charcoal filter.

So that’s what we’re using for areas with smoke. You can you carbon filter as well with the MERV 15? Or just the charcoal itself without MERV 15, that’s an option as well. And uh, just keep in mind that vacuuming this will not necessarily will any make any change because their particles are so small that they are actually inside of this material and not coming out and this is not an inexpensive filter.

I can’t remember exactly how much, but I order my filters uh from the Zhender USA website, what is that? Zehnder America.Zenderamerica.com. They’ve been great about uh, I’ll I’ll order those in there at my house in a week. And like I said, I order them at a big bunch at a time, but this is my last pair of those so I need to order some more of those.

So we have marks on these filters as well as any other filters. It shows where the air should flow, so when we installing them, we want to be sure that we’re following the instruction so air flow from this direction, so that one. So the air coming from here to there, so the arrow is supposed to point that way. And while Szabi’s putting those back in, there’s one more filter that you’re going to have to go through the entire house and hit, and that’s at each one of your exhaust locations.

And we put this cardboard box on here because we spec one in my conditioned attic. This allowed us to commission it, but I kind of like it because it tells people who are visiting what it is. So this is a sucker, this is exhausting. And so uh, it’s sucking air out of my attic. And this little cone filter is just really to keep the duct work clean, is all it’s doing.

So it’s been at least 6 months since I’ve touched it, you can see how dirty it is. It’s not terrible, but I’m going to go ahead and just run that under water upside down uh downstairs, and then I’ll switch it out. And actually have a full set of these that I’ve been doing that with.

So here’s one that still has a couple of particles clinging on there after cleaning, but I left it up here to dry, it’s good to go. I’m just going to pop this back on here, it’s got a little nub on there and if you haven’t seen my other videos, this is really the heart of the system.

They can, when they commission my system, they’re able to change this, uh, damper basically move it in and out with this little dial here, and they’re able to actually commission the CFM. So when, Zhender designed my system, they said here’s how many CFMs we’re trying to either supply into this room or exhaust into any particular room. They dial that in and look at that. That’s all it takes.

So now I’ll go clean that out and I’ll store it back in the attic, but that’s pretty much it on a 2-year basis. Now I just need to come up every 3 months and change those filters, change your filter. But why I wanted Sean here, uh, in particular is I want to have a little conversation about what I’ve learned on this system, uh, with a 2,800 square foot house and with uh four kids and a, a big dog.

You know, my dog’s like 70 lbs or so. There’s a couple things that I feel like I want to change on the air flow now that I’ve been in here two years. And so Sean, talk to me about what positive energy or what you would do in terms of figuring out how much air flow you need because we’ve got two different things going on. We’ve got a local code that requires something, but then we’ve got some kind of national standards. Will you talk to me about that?

Sure, so um, ventilation, um, is something we all need. We all need ventilation to to breathe and when we’re inside homes, uh, lots of things can build up: carbon dioxide, VOCs, um, radon formaldehyde, like all sorts of things we don’t want inside our environments.

And the outside microbiome is going to be way more healthy for us than the inside. So as much as we can bring that air in in a safe way, the better. Um, so that’s sort of where this, this stems from. But Code Compliance has also come in and said hey, we need to be doing this.

And so what what has happened is, uh, the City of Austin has sort of complied with an older ASHRAE standard, so 62.2, and it basically says okay, how much ventilation should we be bringing into these new homes? So Sean, walk me through the numbers on the 2010 ASHRAE and what that would look like for my 2,800 square foot house.

Yeah, so 2010 ASHRAE is going to be 1% of the square footage. So for your 2,800 foot home, that would be 28. Okay, CFM. And then it’s going to be the number of bedrooms in your home plus one. So a master bedroom typically has two people, so if you’re thinking about every bedroom being occupied, uh, reasonably, then that so yours, four bedrooms, four in the house, so 5 * 7.5.

So that’s, uh, 30, what’s it, 37.5? Yeah, plus the uh, the 28 earlier that we mentioned. So that’s 62.5, so 62, 63 CFM is what would be, make what would me code, code compliance, currently under Austin 2010 standard from ASHRAE, exactly which is a heating and cooling, uh, body that kind of regulates or or doesn’t regulate, gives suggestions to that a lot of people pick up as code.

Okay, so 62 CFM continuous all the time, exactly all the time coming in. And uh, what’s interesting about this is Code Compliance, uh, for a long time you didn’t measure this, you just had to have a a box that showed that you were ventilating and who knows how much you’re actually bringing in.

So uh, so I would really like that they’re now saying no, we we need to measure these things, we need to know how much we’re bringing in, not just install the device right? So I think commissioning is key, uh, both with ERVs and with any any ventilation system.

Now positive energy design my house, though, with a newer version of ASHRAE in 2013. They changed the standards. Can you watch through what 2013 would look like?

Yeah, so 2013 is essentially double what the the old ventilation rate is. And that’s 3 CFM per square foot, sorry, 3% of the square footage plus the 7.5 CFM per bedroom plus one. Got and so in this case, number is about 120 or so, right?

Yeah, exactly 122. So pretty much double what the the old code was. And obviously their findings showed that ventilation is so important that there, they want to double it, right? So that, that just shows you that ventilation is an important aspect of living in homes, yeah.

And I, and I think the point too here is that this number is a little bit of a rabbit out of a hat number. There is no specific number perfectly. It’s a design guideline, and Szabi your engineers, uh, when they designed the house for me, took into account my actual family, my dog in the house, how airtight my house was going to be, and you guys actually spit out a number a little higher than that.

So when we commission the unit originally two years ago, my, uh, kind of normal setting was closer to 160, uh, CFM rather than 120. So we me a little bit higher, which a little more I think is a good thing.

But here’s something I want to talk about. My experience after being in the house for two years has been that, uh, my humidity has been a little higher than I wanted it to be. I’m always keeping it below 60, but there are some times where I felt like it was hard for me to do that. My dehumidifiers upstairs and my dehumidifier downstairs were set at a level that would dehumidify anytime I got to about 45% relative humidity, but I had a hard time keeping it down to 45.

I was getting in the 50s or even higher sometimes. And I think that’s because this unit, remember one thing I want you to know, this is the world’s most efficient ERV, but it’s still will raise your humidity if you’re in a hot humid climate like Texas because the enthalpy, the amount of moisture movings roughly what? 80% or so in this unit. It depends on the speed, how much air is coming through the core. It’s between 65 to 85%. Got it?

Now the heat, though, is closer to 90% efficient. So we could do the math on this, but in other words, if if, uh, outdoors is 0 degrees outside and I’m keeping my house at 70, that incoming air is really warm. It’s only a couple degrees less than 70 at 90% efficient on the heat side. But on the humidity side, which is a problem in Texas often where it’s really humid out, it’s, uh, you know, today’s like 80 plus% humidity outside.

It’s real humid, hum and hot out there. So this unit at 60% efficient on the enthalpy or whatever it is, 70% means that I’m still going to raise my humidity in my house because I’m exchanging air. I still want that fresh air. My house smells, feels, uh, I sleep awesome in this house so it’s worth that penalty in my mind.

But what I’m going to do, Szabi, now that I’ve been in here for two years, is I’m going to have you as The Tech Guy adjust my numbers a little bit, and I’m actually going to go down closer to what the 2013 ASHRAE 62.2/64 numbers are. And Szabi’s actually already done that.

So medium speed for me, which is kind of the normal run speed, if I’m saying that correctly, uh, if you look at your app, that’s going to be two of the three bars is medium. And I started on my little Post-It note there, I’m pulling, we’ve changed that to 130 CFM. So pretty close to ASHRAE 62.2.

My low speed, if I want to drop this into low speed, would be 70 CFM. And if I go into, on vacation, if I’m away for the weekend, this has a away feature on here which literally is a button press, and you can say hey, how long you’re going to be away for? Now that’s going to be 30 CFM, so it’s going to move a little bit of air in the house but more like a puff rather than this full speed.

And then boost mode or high mode is going to be about 50% higher than my normal speed, actually a little bit more than that, uh, at 240 CFM. That’s when you’re showering, uh, that’s when you know something’s going on that you’re making humidity, you hit the boost mode in the bathrooms, yes.

And just keep in mind that the numbers, what you see on your app or on the display of the unit, are cubic meter an hour, so don’t mix them with the CFM because this unit is from Europe, so it’s metric. And you will need to convert the cubic meter an hour, what is the conversion just for the fun of it? 0.58 is the multiplier, 0.58, correct?

So you multiply cubic meter an hour with 0.58, correct. That’s when you get the CFM, yeah. So approx when I do calculation in my head, I just multiply with 0.6 because it’s easier to to calculate quick, but just keep in mind when you see the numbers, that’s not CFM, that’s cubic meter an hour. So you want to be sure that if you ask your installer to change your numbers, that you using the proper numbers, not mixing.

Now Sean, I want to ask you about this, and this is one big reason why I wanted to hear Sean, uh, has been in a lot of houses. He’s, he’s seen a lot of issues, a lot of people call him when they have indoor air quality problems at their house. What’s your take on these ASHRAE numbers, what I’ve experienced, and what and what do you think about me changing the numbers now that I’ve lived in the house two years?

Uh, I think that that’s great. I mean, everybody has to sort of prioritize whatever their goals are, and, um, I think that the more ventilation we do, the better. But I don’t want to cause any harm in our hot humid climate. We can definitely grow mold pretty quick if we’re over ventilating or even ventilating to the normal standards without putting the appropriate measures in place like dehumidification.

So it’s really important that we look at the house as a system of inter related systems, and how this ERV system is going to need, now, a dehumidification system or maybe you know, some some other thing, right? Your enclosure is also very much related to this.

So when I go into homes,people really need these ventilators to be on, and very often the AC guy or whoever it is just shuts them off, uh, so they don’t, they don’t ever run because the, the homeowners aren’t really well educated on them actually running or even maintaining, which is why I’m really happy you’re doing this video about maintenance because that’s the other thing I run into is the ERV never gets maintained.

It, the filters never get changed. It is terrible, yeah, way worse than the ones I see here. And what happens is the filter gets so impacted that it bends away and now you’ve got filter bypass, so the entire thing is just contaminated and it’s just really sad to see that. These are the lungs of the home. This is what’s supposed to be keeping us healthy and can potentially have you know, sort of a negative impact.

So I like it. So Szabi any, you want to comment on that at all about changing my numbers from kind of the Zhender engineers numbers to a, short comment just to verify the numbers. So at Zhender, when we design the system, you send us the plan and we design the system. We follow the code requirements: ASHRAE, local mechanical codes, and IRC, right?

So IRC gives us mostly the highest number in every home because International Residential Code requires 20 CFM in every bathroom and toilet room including powder room, kitchen 25 CFM continuous. So in homes with multiple bathrooms now, but we see on the new constructions, people have three, four bathrooms.

That’s easily put your house to 800 CFM even if it’s a smaller home, so that’s a possibility that our numbers, what we design for you, it’s higher than ASHRAE. So your house is over ventilated compared with the ASHRAE number, right? Not because we want to over ventilate your home, because we want the house meet with the code because code officials when they asking for it, they want to see that you getting 20 out from your bathroom, yeah.

So when you have hot and humid climate and extreme, crazy weather up north extremely cold and dry, down here extremely hot and humid, or even up north unfortunately we have not hot and humid days too during summer time, what you can do is you can manually lower the speed of your unit to low speed. And when the unit goes to low speed for that 1, 2, 3, 4 days, you will do a better performance on recovery on energy and enthalpy, oh that’s a great point.

So you will not move that much humidity into your house. So instead of jumping on to recommission and change the settings on the unit, the easy way is just change the speed to low speed, go into low speed and, and uh, you know, you made a great point that that, uh,

I haven’t honestly thought about until just recently, which is this core that’s in here that’s moving the airstreams near near each other and moving the Heat and the humidity is most efficient when it’s on low speed because the air is lazily moving through there, more of that heat and enthalpy can change. But if it’s on high speed, it’s zooming through there, it’s not able to be as efficient.

So you make a great suggestion. Drop this into low speed and see how that feels, uh, so the air path is slowed down, it’s going to do a better job of moving the moisture through the core, the heat through the core. That’s a really interesting tip to, you know, cuz ultimately again, all these numbers, yes, there’s some math involved, but these numbers have been pulled out of the air by a bunch of smart people.

Don’t get me wrong, but it’s honestly, uh, a guide, not an actual number. And so you have to see what your house does, how it’s like living, how you feel living in the house, uh, with that being said.

I want to ask you, Sean, about your experience with dehumidifiers and, uh, especially thinking about southern but also Northern houses. How does that dehumidify if work in concert with an ERV?

That’s a great question, um. I would actually just like to comment on what you just said about how the home feels. So our bodies are great at telling us lots of different things about temperature and things like that. There are lots of other things that our bodies are terrible at, and you know, colorless, odorless gases, right, like so radon for example, some VOCs and you have no idea, right?

And so, um, it’s important that you don’t just rely on feel, and it would be really nice if everyone were doing some sort of indoor air quality monitoring, ah, at least temperature and humidity, but some other things. And obviously these monitors are not going to tell you everything, so it’s sort of flawed in that way, but at least you have some metrics to sort of go on as to whether or not we actually need to to ventilate, uh, carbon dioxide is another one that builds up and we don’t know except for we get drowsy or whatever that is.

So, um, so anyway, so yeah, so I think that that, that’s going to be important. But in our um, and and to that end, uh, monitoring those things and monitoring humidity is really going to, uh, tell you whether or not you need to dehumidifier as well. So if, if we’re not measuring, we don’t know if that dehumidifier is needed.

But in our climate, if we are ventilating, we need to be dehumidifying. We have a big moisture problem here. I’m a huge fan of separate dehumidification. And I’ve also learned on two-story houses, uh, I don’t, I don’t ever try and heat and cool a two-story house with one system. I also don’t dehumidify a two-story house with one system.

So in my house, I’ve got a smaller Santa Fe upstairs, a 70 pint Santa Fe, and then I actually have recently changed out my downstairs unit to a bigger unit. I have a 98 down there, uh, instead of the 70 that I originally had. I swap that out, and so I’ve got a little bit more capacity. And that’s one thing that I think I’m going to take away from living in this house for two years. I kind of like Having excess capacity on my dehumidifier, yeah.

I think that’s a great idea. There, there’s a number of things that are really great about that. It’s really hard to oversize a dehumidifier unless you’re in a really small space where you can get a lot more heat in there. So as long as you have a reasonable size home or reasonable space you’re trying to dehumidify, putting the biggest dehumidifier in that you can, uh, is really going to help that thing function when you have extreme loads.

So like, let’s say that the doors are open or a party or something like that, but it’s really going to help to, um, dry out the house quickly and efficiently, uh, when things do get wet. And it’s also probably going to reduce my run time so that I’m not running 24/7 on a small unit, which means I’m going to put more wear and tear and maybe have to change that unit, exactly, yeah. So the less it runs, obviously the less like it is to fail sooner. So yeah.

Now Szabi, your house back in Pennsylvania, you have a, uh, Zhender Q just like mine. You got some other cool stuff going on that we won’t get into, but you also have an air quality monitor at your house, uh. Talk to me about what you found with your air quality monitor.

So yes, I have the same unit what you have here. I have multiple air quality monitors. We at Zhender be selling the CO2 monitor what you can attach to the unit. So at the CO2 level goes up, you have a party or higher occupancy, or just cooking for Thanksgiving which is coming with a propane oven, yeah, your CO2 will go up and the unit ramps up automatically.

It senses it and it starts to bring in more air. The other monitor what we sell is the relative humidity monitor. So in the bathrooms in your house, you have the switch what you have to push. My kids don’t have to do that because you have a relative humidity switch that will, not switch, just a sensor or sensor rather, oh I like that.

So my kids’ bathroom, we don’t, we have the switch but they don’t push it anymore. Is that a wired or Wireless? A wired sensor, okay. So but we introducing the new wireless CO2 sensor next year and wireless switches for the boost mode as well, oh that’s super cool. I like that.

There are multiple monitors on the market. We’re not talking about brands, but they are pretty affordable, couple hundred dollar, pretty reliable monitors. They can even hooked up to Smart devices, cell phones, tablets and it’s really worth to invest money into it because what I learned in our house, for example, example in the first three years, we had extremely high radon.

Pennsylvania is high on radon, so our radon level was around 16, 18, woo, that’s that’s really high. Anything over five is considered a problem, right? Four and above, four and above. So I install the fan, the house is done now, too, which interesting is you can see how radon is floating based on water table, barometric pressure, and even our dryer. We have a vented dryer.

If my wife forgets to open the window in the laundry room for makeup air for your dryer, negative pressure will brings the radon up to even your 200 CFM dryer puts enough pressure on that soil gas that your radon number goes up without having makeup air for your dryer, correct? Our house is .14 on air change, so that’s the biggest, that’s the, if you’re watching still on this nerdy video, do not forget that. That is fascinating.

So tighter is the home, more weird things start to happening inside. I’m living in one with the family and I can tell you that things what we didn’t even think about popping up, yeah. And this is my life. I’m eating this for breakfast, lunch and dinner. This is what my life is, so I monitor everything all the time and I’m look for trouble. And um, a smart home needs a smart homeowner, yeah, because if you don’t have that, you can put it down very quickly, yeah. That’s a great point.

So maintenance is extremely important, not just on the ventilation, it’s on your HVAC as well, yes. Your, dehumidifier has a filter, yep, that needs to be changed, yes. So everything, filter is the easiest thing to do is the cheapest way to keep your house healthy and safe, yep, like changing oil on your car. Don’t miss it once, correct?

We’ve gone long but there’s one more thing I want to ask from you guys before we leave, and I want you guys to get your unfiltered comment. I didn’t prep them with this, uh, you know Zhender is the world’s best system, uh. I think it’s also the only system out there that really ducts correctly with your fresh air, uh.

I love how each bedroom gets its own source, but you know, there is this push back I get from people as I talk about this, oh Matt it’s an expensive system, you know?

I can’t imagine my clients being willing to pay for X, Y and Z. I’ve lived with it for two years. I’m specking these in my houses. I’m using these all the time now, uh. I don’t really give my homeowners a choice very, very often sometimes, but I’m curious from, from you guys, uh, how do you sell a system like this to a prospect, to a client, to a builder? Give us the two-minute elevator pitch on why Zhender, and why a system like this that costs more than just, uh, a fresh air input to the return side of a furnace or a ventilating dehumidifier?

I wish we could bring customers into this video because they could tell you exactly why they are loving our system, yeah. That’s me there. I’m a salesperson for Zhender, so I’m a little bit biased, but the system is great, but you have one in your house too and experienced it. So my wife is happy because we have no dust in the house. How about that? Because the air is filtered, so there is no dust in the home.

The bedrooms are nice and quiet. Ventilation doesn’t make noise. Our boys’ bedrooms are good smell. There is no boys’ smell in the bedroom. I don’t smell at all and I have three boys in one bedroom. It’s moving the air continuously. Our old house, it was always a challenge to open the door at the morning, so this is designed specifically to move air.

And as you mentioned, it’s neither a dehumidifier, neither a humidifier. The only purpose for Zhender unit is bringing in fresh filtered air and put into the proper rooms where you need it and pull from the rooms where we want to move it out with contamination.

A quick note on your piping, lots of customers seeing your videos and they asking the white pipes, right, right? So Zhender is selling, we were planning to bring a piece of the flex and I forgot it, but flex is the new pipe what we’re selling. So so in other words, this white pipe you see here, this is an older spec. Now the pipes are gray pipes, correct? The new flex is a greenguard rated, UL rated pipe, and that’s what we sell mostly in United States.

So the unit technically sells itself if somebody use it and put the word out and talk with other people, they can tell you exactly why they love our system, totally. From me to telling you that it’s expensive because this is the best, that’s a true, but I’m biased because I’m living with this. You get what you pay for, but you get what you paid for.

And uh, the maintenance is very simple, even the service is very simple. So this is a mechanical equipment like any other unit. It needs maintenance. Sometimes sensors needs to be replaced, easily.

You just changed a sensor on your unit, yep, easily accessible, super easy. I mean, this is going to be here for decades to come and if I need to change something parts wise, it’ll be available. I can get it from a long time and you’re not going anywhere, a small company since 13 years in United States with no problems here and there, some sensor issues, cleaning and maintenance is that reason.

So we’re bringing you air where you need it, clean, and it’s the same temperature as your house. So as you mentioned, the efficiency is so great that this air which is coming here on this pipe in a Delta 70, the temperature difference is only 6 or 7° with 90% efficiency. You don’t feel it, you can’t tell, don’t have draft, no, you have no idea. It’s amazing.

Sean, your turn, elevator pitch. ERVs, maybe Zhender in specific, but fresh air, why do you, why do you think it’s important for people to have one of these in their house?

Definitely, so when I talk to clients, it’s really about what their goals are for indoor air quality and then what their budget is to achieve those goals. So if they have a lot of, um, sort of demanding goals, and then that means they need to have a slightly bigger budget to achieve those things.

And uh, I think, think Szabi hit on a lot of great points that, uh, this is going to be quiet, this is plug-and-play, uh, materials that are easy to change out, um, they’ve got an awesome duct system, uh, less duct leakage. Uh, duct leakage is a major thing, especially on ERVs that are running all the time, uh, and how that can also impact indoor air quality from those things, um.

So they’re trying to set things up for everyone to succeed for the contractor to make it easy to install. And so, uh, there’s a lot of great things that Zhender has going for them, which is why, why they’re the best.

And if you just, you know, we say that they’re the best, we don’t have to say it. You just look at the specifications, you look at their performance data, and you go oh, this is way more efficient than than other ERVs. So, um, so that’s, that’s why, uh, it is a, a big, a big cost delta, but again, depending on your goals, I, I think it’s worth it.

So all right, here’s my, here’s my Quick Pitch that I’ll, I’ll give my Builder friends in the audience. Here’s, here’s an analogy I, I stole from Steve Baczek that I really like. You know if you’re in your car and your engine is not running, your windows are up, you’re in a zoom call in your car, no matter what the temperature is outside, how long does it take you to get uncomfortable in your car sitting there?

Not long at all. I mean, you’re talking maybe a couple minutes before you’ve got to crack a window or turn the engine on, right? Now, I could take a zoom call for 30 minutes in my car, my truck outside, no matter the weather, and I’m generally speaking pretty comfortable as long as the engine’s running. This is your small engine that’s running and keeping you comfortable, bringing you fresh filtered air to all your bedrooms all night long.

And you’re spending money on your health in all kinds of ways. You’re drinking fancy beverages, you’re buying organic foods, you’re, you’ve got a gym membership.

This is an investment in your health. I sleep amazingly well in this house and all of my kids get filtered fresh air all night long. And so this is a reason for me to build a really tight house and to ventilate that house correctly. And the Zhender is a big part of that. It makes my house super comfortable.

Guys, thanks for hanging in there for a really long video. I’ll put a link, uh, to Zhender below if you’ve got a project coming up, you’re interested in one of these. You can get a quote from Zhender and they’ll help you find an installer, the whole shebang. They’ll design it for you. So put a link to that.

If you’re in Texas and you’re interested in talking to Sean, IAQtexas.com, sir, is his company. Sean’s actually a very multi-talented guy, uh. He also owns the Arab barrier dealership here in, uh, in town, uh. You’ve seen him on a bunch of my videos running the blower door, doing building science investigations, longtime friend, super smart guy.

And if you’re not currently a subscriber, guys, hit that subscribe button below. We’ve got new and extremely nerdy content here, plus over on buildshownetwork.com, uh, that we publish here on YouTube every Tuesday and every Friday. Guys, you know my outro, right? We got to, you got to help me out with my nerdy outro. Follow me on TikTok or Instagram, otherwise we’ll see you next time on the Build Show.

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Fresh air: A quality ERV that most can afford?

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