Is glass in our windows making us sick with Joe Menchefski

Glass, Sunlight & Human Health

In the first episode of Series 2, we’re joined by daylighting expert and chemical engineer Joe Menchefski to explore a critical but often overlooked topic in modern building design: glass.

While low-E glass and LED lighting have dramatically improved energy efficiency, emerging research suggests they may also filter out parts of the light spectrum essential for human health.

Are our buildings optimized for energy — but not for biology?

🌞 What We Cover

• Why humans now spend 90–95% of their time indoors
• How low-E glass works — and what it blocks
• The possible link between filtered light and rising childhood myopia
• Why full-spectrum sunlight matters for eye development
• The impact of LED lighting on circadian rhythms
• Blue light, red light, and mitochondrial health
• The balance between energy efficiency and human wellbeing
• Vacuum-insulated glass (VIG) as a potential breakthrough
• Passive design, orientation, and smarter daylight strategies
• Why architects are beginning to rethink glass design

🔬 Key Themes

• Full-spectrum natural light is not just visual — it’s biological
• Buildings without proper daylight may impact sleep, metabolism, and productivity
• Energy efficiency alone is not a complete design strategy
• Health-optimized building design is an emerging frontier

🏗 Why It Matters

From rising myopia rates in children to circadian disruption in adults, the way we design windows, façades, and lighting systems may be shaping long-term public health outcomes.

This episode kicks off Series 2 by asking an essential question:

Are we designing buildings for performance metrics — or for people?

Read the accompanying blog here: https://shadowmap.org/learn/are-our-windows-making-us-sick

Sunlight Matters is a podcast exploring the role of the Sun in human health, architecture, cities, and everyday life.

Through conversations with scientists, architects, and technologists, the series examines how natural light shapes our bodies, our buildings, and the way we live indoors.

Hosted by Dave Wallace, Sunlight Matters asks a simple but overlooked question: what happens when we disconnect from the Sun?

Because sunlight isn’t optional. It matters.

Please do not forget to Like and Subscribe. 

Transcript

Introduction and why this season begins with glass.

Speaker 0:03

Welcome to Sunlight Matters, the podcast that reconnects us with the sun. Join us as we explore the power and influence of our star, the force at the heart of everything. Each episode, we speak with leading experts to uncover the ways sunlight shapes our world.

Dave Wallace 0:20

Joe, welcome to the podcast. This is podcast number one of series two. So we're delighted to have you. It's um early January 2026. Uh and today we're going to be talking about glass. So I think in the the series one, we went into quite a lot of detail with various people about uh the impact of sunlight on health, wellness. We talked to people about the built environment, about lighting. Um, but the one thing we didn't touch on was glass. And uh, you know, I think this is a is a really important topic because you know, we all live in in buildings, we all work in buildings where glass is a prominent feature. And I think we're gonna go into a lot more detail about the fact that much of that glass is stopping the good rays, the good um uh aspects of sunlight coming through. As I said, welcome to the podcast. I wonder if you could just start, Joe, by giving us a briefer introduction to yourself and and what you do, and then we'll get into it.

Meet Joe Menchefski: Background in daylighting, glazing, and building science.

Joe Menchefski 1:31

Sure, sure. So Joe Menchevsky, I'm from lovely Nova Scotia, Canada, uh on the extreme east coast. I'm as close to Ireland as I am to uh uh Washington, D.C., where I sit. Uh I I am uh I'm a chemical engineer by training. I started my career uh early in my career, I got into I was extruding multi-walled acrylics and polycarbonates for uh um originally for greenhouses, and then that led into sunrooms, which led into skylights, which led me deeper and deeper into the world of architectural daylighting. And I continue, I continue to go down that rabbit hole. Work uh I'm an independent consultant. I do some work with the Green Building Initiative, but my primary client is Advanced Glazings. Uh and and my primary commitment is to a company called Advanced Glazings uh in here in Nova Scotia. Uh, and we do architectural daylighting. Um so, you know, a home with no windows, a building with no windows, a building that does not connect us to the natural world is a crappy building uh for a lot of reasons. First of all, it's just lousy to be completely isolated from the natural world. It's lousy to be isolated from our community. Uh anytime we find ourselves in buildings like that, you can feel the agitation. Um it just doesn't bring us as much joy as when we have some level of connectivity. Now, so you know, a long time ago we we developed glass, we developed windows, and and that allowed us to have those connections to the natural world. Um, but when we put, you know, when we punch a hole in the in the facade of a building uh in order to put in a window, there's a couple of things that happen. I mean, first of all, we lower the energy efficiency of the building itself, which is a huge deal these days. Um, but secondly, you know, we can create glare problems. We can create thermal discomfort, uh, you know, intense solar, solar heat gain. Uh, and in the wintertime, thermal discomfort from from how rapid we lose energy when we're close to to a low insulating window. Um, so, you know, one of the things, some of the things we've done to deal with that are very good. And some of the things that we've done to deal with that are questionable. And that's the that's the word I can use at this point, and I'll explain that in a minute. So let's talk about some of the things that we've done that are good. Uh, you know, first of all, like the company I work for, Advanced Glazing, uses light diffusion. So, you know, some portion of the window or is separate from the view portion of the window, you diffuse the light. And by diffusing the light, you eliminate any issues with glare, you eliminate uh that, you know, intense solar heat gain you feel, like, you know, like when you're sitting at the airport and this half of your face is on fire and this arm is on fire, uh, right? You you eliminate that when you when you have diffusion. You control the light, you make it soft, you make it, you make it gentle, you make it more enjoyable, right? And also with a diffuser, you could have very high levels of insulation at advanced glazings. We put uh um we we we use aerogel to to to have extraordinary level extraordinary levels of insulation for for a glazing for a window. Okay, so that's that's one part, that's one example of some of the good things that are happening. And there's a lot of other good things that are happening that we can we can circle back to. One of the things that's happening that's questionable uh uh relates to the steps that we've taken in our windows uh to try to improve the energy efficiency while maintaining the clear view, which is so so so very important. And um the the uh world of lowy glass, uh so low E glass for for people who don't know, and almost every every new home built now, every new building built built now is built with what's called low E glass, and the E stands for emissivity, right? It's a coating that you put on the glass to and it reduces portions, blocks out portions of the light spectrum, both the visible light spectrum, like the part of the light spectrum that people can see. If you remember your grade eight uh science class, they they'd say uh Roy G bib, red, orange, yellow, green, blue, indigo, violet for for your rainbow.

Dave Wallace 5:54

Richard of York gave battle in vain, so I still remember it.

Low-E Glass & The Light We’re Blocking. How modern windows improve energy efficiency — and what they filter out.

Joe Menchefski 5:58

There you go, there you go. Yeah, yeah. So, so you know, we all know that. But just you know, just past the red, just past the R, there's there's infrared, which is the part of the light spectrum that's heat, right? The electromagnetic spectrum that gives heat. And then at the other end, just past the violet, is is the is the ultraviolet, right? Which we everybody, I think everybody understands ultraviolet. Um, and and so we we can improve the energy efficiency of windows, and we've clearly demonstrated it over many years, by cutting out, you know, those two extreme ends that are visible in the light spectrum. Uh, and we do that through this this low E coding. Um there is some research happening right now that is suggesting that the portions that we're cutting out in the light spectrum can have very negative impacts on our development at an early age, okay, like up to about the age of five. Um shall we dive deep right now? Or they go right into what the research is showing.

Dave Wallace 7:00

Well, no, I think, I mean, we may as well, we may as well follow you down the rabbit hole because um, you know, I think, and then we can come back and sort of broaden it out again. But yeah, no, please continue.

Myopia & Childhood Eye Development. Emerging research linking full-spectrum sunlight to proper eye “calibration.”

Joe Menchefski 7:11

Okay. I'm gonna I'm gonna step back just a tiny little bit and I'm gonna say this. Look, we know that humans now are spending 90 to 95% of our day inside, right? Like less than 10% of our day is spent outside. We are discovering more and more every single day how important it is for our bodies to have sunlight. Now, when I first got into this world, that was all, that was all like new age. Yeah, it was all, it was all like hairy fairy sort of hippie stuff, right? They get out in the sun, it's better for you, it's healthier. Right, gotcha. But now we're finding that there are actual processes, multiple processes in our body that depend on our access to sunlight in order to keep us healthy. Okay. And I'll and in a little bit we'll circle back to some of those processes. Um, but right now we're gonna focus on one related to glass, right? And I'll tie this back to LED lights and all of that as well. But the one related to glass is myopia. All right. So there is a massive global epidemic in myopia. I'm nearsighted, um, but but this is purely genetic, and I I'm too old to be part of what's what they believe is happening now. So, you know, scientists have have known about this myopia epidemic for some time, 10, 20 years, and they've looked at things, you know, the the obvious culprit is is all the time we spend on glowing screens, right? Like the people who may be watching on YouTube right now or watching on their phone, watching on their computer, watching on their big screen TV. That's what has been assumed to be the cause. Now, the current research, and and let me emphasize that this is not herb accept sorry, it's not broadly accepted science yet. And I'll tell you why in a little bit, why there's still some controversy. But we've discovered that you know, when you are very young, your eye basically needs to focus. It needs to learn how to focus. And it literally changes the shape of your eye. Right. And so there's portions of the light spectrum, especially down near the violet end. Remember the last time we chatted, I told you that it was up near the red. I was completely wrong when we spoke about that. It's down near the violet. It's somewhere around a wavelength of 380 nanometers to 400 nanometers. When you're very young, your eyes lock onto that portion of light coming from the sun. And they use it to adjust, literally adjust how like the how how round versus how like egg-shaped your eye is, right? It it it it it flattens or or it goes this way or that way. And the tuning comes as a result of this around 380 nanometer wavelength, which is incredible, right? And and in the absence of that portion of this of the light spectrum, the we like the the lens or the the eyeball doesn't find the right shape, it doesn't find the right length, and it doesn't focus properly, and we end up with nearsighted people, myopic people.

Georg Molzer 10:40

It sounds like a calibration process you undergo in your early ages, and if you if you do not have this calibration process, it messes up your eyesight.

Joe Menchefski 10:50

That's a brilliant way to put it. That's a brilliant way to put it, Georg. It's a it's a calibration that without that particular wavelength, the calibration doesn't happen. And that seems to play a major role. Now, I mean, the obvious solution to that is go outside. Take the kids outside, get them out in the sun, and that'll help with the calibration. But some portion of the children's day, especially depending on the climate that you're in, is going to be spent inside of a building, right? And a lot of the light comes through windows. Now, low emissivity glass, as I said earlier, is increasing energy efficiency of windows by blocking out a portion of the visible light spectrum, right? That that um is is unnecessary. Well, you're you're holding the energy in in the in the uh wintertime and holding energy out in the summertime. It just stops a complete free flow of energy through the window. And it does that by chopping out a portion of the spectrum, and somewhere around 380 nanometers is where it cuts off. Okay, where low E-glass stops you know, electromagnetic magnetic light from coming through your window. It's somewhere around there. And and this is where the controversy comes from, and this is why I can't say that this is hard science yet, or sorry, it's broadly accepted science yet. It's it's looking this way, like this is where it's going, but it cannot be said, it cannot be confirmed that this is actually happening yet, right? So glass industry don't quite quite panic, don't panic yet, and and don't panic anyway, because the the solution is really, really simple. Um so so it's possible, and the theory that's being studied now, and being studied by some, you know, uh consequential players, you know, Lisa Heshong, uh sort of the the godmother of sustainable and healthy building design is is one of the people leading these leading this effort. It looks like it's possible that the lowy coating is cutting off just enough of that light around around 380 nanometers to stop the calibration process from happening for children who are spending most of their day inside. Right? So that's a huge issue, right? That's a huge issue. I mean, we need those windows, we need the sunlight, we need energy efficiency, um, but we need to make sure that our kids, especially the very young, are exposed to full spectrum natural light. Two ways to achieve it. I mean, one is you go outside, take the kids outside. That's that's my favorite, right? But but but beyond that, we need to make sure that our children are exposed inside to some portion of the windows in our space in our in our living spaces, in our working spaces, in our school spaces that have full spectrum light transmission.

Georg Molzer 13:59

Directly asking a question which might our listeners think is obvious. When we talk about low E, it's about um low low um like higher energy efficiency. So I would assume it it it's it's more about infrared so that the the heat from the outside doesn't penetrate the indoors. Um that's the infrared spectrum when when you say that it's the UV spectrum that would benefit um childs in developing proper eyesight. So how does the the low E glass like why is it even filtering UV light when when it's not really is it an aspect in in energy efficiency or is it it is, it is.

LED Lighting & Circadian Disruption. Blue light, red light, sleep cycles, and metabolic implications.

Joe Menchefski 14:35

I mean there's still energy in low E or sorry in UV. It's not you there's not as much energy as there is in IR, but there's energy in UV too, right? And you know, the other reason that you that's some people would would argue that you don't want UV coming through your windows is it fades your furniture, it fades your rug, that sort of thing as well. So it it does cut off the the you know a portion of of of the UV spectrum as well. So it's both energy and and and and uh you know that that other advantage. Um so you know the the I think the bottom line on all of this is that the world needs to recognize that full spectrum light is way more necessary than we had ever imagined. It's it's so tightly tied to some basic functions in our physiology that if we take any steps, you know, and I'm not I I do not mean to pick on low E glass at all. I mean, I work in the glass industry. Um, and and and like I say, the solution is really simple. Get the kids outside for a portion of the day and have you know i if you if it's a it's a uh a preschool or what what do you call it in England, Dave. Nursery or preschooling nursery, kindergarten, preschool, Georgia in Austria, how would you kindergarten, I think you say. Yeah. You just would need a room or a portion of that of those buildings that have full spectrum light coming in. So it's not really a big panic or anything, but it raises the the the issue. It really, really brings to to you know to the forefront the issue that full spectrum light is just so critical to us. Let's talk about some of the other things. Uh, you know, LED lights, for example. Just like a low E coating, an LED light reduces energy consumption, which is important. It reduces energy consumption by chopping out portions of the light spectrum, right? So so they tend to have a lot of blue and way less red, because as it's as we spoke of earlier, red has more energy, right? So they chop off the infrared, and they they leave out the infrared and and they leave out a little bit of the long range, little long wave red as well, like the actual visible red disappears from the LED lights. We need that. We need that that infrared and red uh for a number of reasons. I mean, there's there's serious research happening at the University of College of University College of London, uh, there's real research happening at Oxford. I, you know, the some of the original pioneering work was done by Dr. Russell Foster uh at Oxford. Um and and so not only do we have low E glass that's robbing us of full spectrum light, when we when we are inside in a situation where we don't have daylighting, proper daylight, and we don't have full spectrum light inside of a building, our LED lights are partial spectrum. Uh let's talk about two of the issues that we know of so far. The big one is circadian rhythms, okay, our sleep patterns. Uh it was Oxford, uh again, Dr. Foster that found that actually identified the proteins um that that control our 24-hour clock. You know, our bodies have to be synchronized to the 24-hour turn of the earth, okay, because we have scheduled things that happen, scheduled processes that happen in our body. And if they happen at the wrong times, it's not ideal. And we could sorry, I could get somebody in here who could talk about that. The depth. It's not my area of specialization, but I know that we're with I'm honestly, I because you know, I have the Better Buildings for Humans podcast as well. And I hope and I I like to talk about this particular subject matter a whole lot. So I'm constantly learning something new about all the research we're finding about how important it is to have that light and have certain things happen at certain times. If we don't have access to it's a it's a part of the blue light spectrum around 480 nanometers, if we don't have access to that, you know, on a regular, uh on a regular basis, like basically every day, our body will start to slip off the 24-hour clock. Um, and and uh, you know, we'll start, you know, waking up at night and going to sleep a day. That's the extreme. But even if it shifts an hour or two, right, three hours, that can be unhealthy. That can be extremely unhealthy. Um, and and and LED lights, you know, chop out a poor, you know, like a uh a warm LED light chops out a lot of of the 480-nanometer blue. It also chops out a lot of the red. Like there's some of the LED lights that chop out a lot of the red. And the red is near the end of the day, you know, to help us sort of calm down. Blue wakes us up, blue make lets us know, hey, it's daytime, go do the things that need to be done. And then the when and you know, as the sun sits on the horizon, sets on the horizon, we all know the horizon starts to turn orangey red, right?

Speaker 4 20:02

Yeah.

Joe Menchefski 20:02

It goes from blue to orangey red, and we need that red. That red is sort of the, hey, human, time to go to bed, right? Time to sleep. Um and that's gone from LED late. So if we're not outside or we don't have a window that's letting us know that that the red is, you know, that that that red doesn't go into our eyes and tell us um that it's time, then our our our synchronization, or they the word they use is an trainment to the 24-hour clock falls apart. And we know, I mean, we back to you know our younger years in school in science, we they learned taught us about rods and cones in our eyes. There's all kinds of other receptors in our eyes uh that that are that are non-image forming receptors that take the light and use it to start and stop processes and and and also control our connection to that 24-hour clock. So we've got a double whammy happening right now. We've got the the the light, you know, the some critical portions of the light being blocked, potentially being blocked by low E-glass. Again, the science is not settled, right? Uh and and we know for sure that a there's there's portions of of the light spectrum from LED lights that that are just not there, or sometimes are there in too much quantity. Everything up in our systems were built around the sun. I mean, how however long humans have been here, we've relied on that. And it's only been fifty, seventy, five, maybe a hundred years that we've been inside.

Dave Wallace 21:38

Yeah, I I mean it is really interesting because it's uh I mean, the the other thing that UCL are finding is about metabolic diseases. So, you know, the lack of long wavelength light is impacting people's metabolism. So, you know, you mention UCL, but Glenn Jeffreys done all this research where they've shun infrared on people's backs and Seen their eyesights improve because of mitochondrial function. And it it it's fascinating because you know, again, I was talking to someone from the Middle East this morning, um, you know, about this very topic because the Middle East is basically glass and LED heaven, you know. That's you look at the kind of design of the buildings there, it's all all glass, all LED lighting. And you know, he was saying that in Kuwait the rate of diabetes is 40%, you know, in the UAE it's like 22%. So you you know, be kind of I'm not sure about things like myopia, but you're really starting to see the consequences of this being played out. Now, obviously, there's other factors which you know would include food and uh lack of exercise and all these other things, but this is definitely something which is kind of happening, and I think you you know, again, just Glenn Jeffrey talks about this as in the same it's it's like the asbestos crisis. This is happening and you know we need to really address it because if we don't, then you know the consequences long term are gonna be bad. And but you know, exactly what you're talking about about kids. I mean, that's that's so fascinating to me that we've got a natural process which is about calibrating people's eyes, and you know, we should all I guess we should all know about this stuff, but it's only now where this is sort of starting to kind of emerge as uh as as a science. And I I think you know, one of the things I'd quite like to understand is from a glass point of view, like you know, I'm sat in a beautiful kind of uh home office, I'm staring out at this lovely view across, you know, I actually do have a nice view, so I I appreciate the view, but I'm I know that beyond the view, and the importance of the view, as you kind of alluded to, is kind of super critical to our well-being, but beyond the view, it it's kind of pretty useless, to be honest with you, in terms of the other things that you know I should be expecting or or should be needing. And it's kind of difficult to phrase it in the right sort of way. And I I know this glass is lowy glass as well. So, you know, what are some of the things that you think the industry should be thinking about in order to adjust for this?

Rethinking Energy vs. Human Health. Are we optimizing buildings for energy — but not for people?

The Future of Glass: Vacuum Insulated Technology High-performance transparent insulation and new daylighting solutions.

Joe Menchefski 24:32

I think the industry is already thinking about uh things that are going to help, um whether or not it's specifically related to uh to the low E slash myopia crisis or the myopia crisis at all, we're heading in a direction where we're going to have transparent glass that's going to have very good insulation properties. You know, uh again back to my own work with Solera, um, it it's full spectrum light, it's soft diffuse light. So the the the bringing full spectrum natural light into the building, we've got that one licked with with diffuse with light diffusers. Um but we need view too. I mean, you look at Michael Kent's research uh at the University of Singapore, uh well, uh even going back again to Lisa Heshong's research in the 90s, um, we are better with views. We're better with full spectrum light, we're better with views, we're better when we have both of those things, right? And that makes a whole lot of sense. Uh, Mike, Michael's work is taking it to a whole other level. He's even he's even being able to quantify, you know, view quality and and and finding correlations between higher view quality and and and improved health. So interesting. We know view matters. We know we have to have the view, we know we have to have the connections to the natural world. Our bodies, we're not meant to be in caves all day. Okay, we just we just can't do it. So back to your, you know, the the heart of your question, which is what are we doing about it? Um, we're already the the industry is already moving. Uh, I think, and this is Joe Manchevsky's opinion, entirely my opinion right here. There's there's two there's two horses in this race as far as I'm concerned. What one of them is is um vacu uh vacuum insulated glass, right? Uh, which is kind of where my money is. And then the other one is uh like these multi-pane glass units. Now, multi-pane has some really consequential issues. You you know, the the um when you get past two, you get into th triple pane, even quadruple pain, uh, you got a lot of weight, right? You have to completely change all the glazing, like sorry, all of all of the framing materials, right? Because the pockets get bigger and bigger and bigger. Yeah, yeah, yeah. And the and it's way more expensive, right? You know, glass is not super, super cheap. It's quite affordable, but it's not super, super cheap. So when you start going from two to three to four, you're raising prices, uh, but mostly it's the weight that's the big problem. Now, the good people from Apple gave us, you know, gorilla glass, which means we now know how to manufacture thinner panes of glass. So you're gonna have the two thicker outer panes and thinner inner panes. But you still need, you still need a bigger window, like a a thicker profile. And I'm hoping that I create some controversy and somebody from the industry comes on and says, I gotta counter everything that that Joe Manchevsky says, because it at least it gets the conversation going.

Speaker 4 27:30

Yeah, no, no.

Joe Menchefski 27:32

And I recognize that I don't know everything. So I'm I'm I'm looking forward to the opportunity to have someone come on and correct me. But but uh because of you know the weight, because of the complexity of having to put multiple panes of glass into uh into a unit, that's why my money's on VIG, right? So are you familiar with the vacuum insulated glass?

Dave Wallace 27:52

Well, can you can you just explain it? Because Sure.

Joe Menchefski 27:55

Sure, yeah, absolutely. So, so you know, a lot of heat transfer happens as a result of the movement of air. Air is not a very good uh um heat conductor. It's not a very good heat conductor, but when it's moving, it's a very it it takes the heat that it has and moves it somewhere else. Okay. So a lot of like the reason we use aerogel is the aerogel stops the air from moving around and transferring some of the heat, and you can get very high levels of insulation as a result of that. But if you can take the air out altogether, just completely eliminate the air between the two panes of glass, um you then there's no air to move around to trans to transfer energy.

Dave Wallace 28:39

That makes sense.

Joe Menchefski 28:41

Now, again, the you know, this gorilla glass, this ability to make very, very thin strips of glass, you can take, you know, say like a six millimeter glass, your quarter-inch glass, which is very typical in commercial construction. It's m most residentials probably like three, four millimeter. You can take two very thin pieces of glass, connect them only at the edges with a little bit of space between them, so you've got a tiny, tiny little space between these two thin panes of glass, right? And then you suck all the air out. Right? So in a normal six millimeter piece of glass that would be typically in every commercial building, modern commercial building in London, in in Vienna, um now that single pane of glass, because the center of it has been removed, essentially, it's got a gap, and there's no air in that gap, that single pane of glass, which is normally uh, I'll speak in R value, normally an R1, you know, the current the current products are as high as R20. Right? We're talking about a 20% improvement in energy performance. And now if you have, you know, a typical IGU in this insulated glass unit, which is like your two panes of glass, which is almost everything now, unless you're in very warm places, um, two panes of glass and both of them at R20, you now have a window that's you know in some cases exceeding the performance of the opaque material on the side of your building, and you can still see through it. So, you know, just think about it. That's a 40 times improvement versus, you know, low E glass takes you from R2 to typically about an R3, maybe an R4. So a 50% to 100% improvement versus 2,000% improvement. And that's and it's real. Like that, you know, VIG is very, very close. And I think that's gonna make a huge, huge difference. Um, so you'll have things like Solera that have the main purpose of being for daylighting because it's full spectrum and because it softens the light, spreads it deeply into the building, and gives you a, you know, a lot of illuminated area. But you're not gonna be sacrificing anything in terms of energy on the view glass because of these radical improvements in energy performance of the glass itself. There's a lot of really interesting products happening with multi-pane too. Um, and I might be wrong about which horse wins this race, but I honestly my money's on the vacuum insulated glass because it's just such a lovely solution if we can ensure that it's affordable.

Georg Molzer 31:34

Sounds amazing. Um, it reminds me of something we also chatted about in the past, which was like the specifications of the material itself, so so glass as we all know it, versus um, I mean I've looked this up a while ago, it was about animal shelters, and they use some acrylic um pseudo glass, and that has a much higher um transmittance of full light spectrum. So you you say that glass itself is not a problem, and it could even be the material of glass as long as there is like a vacuum uh between two glass layers?

Joe Menchefski 32:09

Yeah. Well, I let me let me back up on that a little bit. Yeah, if you can get the vacuum between the two glass layers, you can get a very, very good level of insulation. Acrylic is the best of plastics in terms of glazings. It lasts the longest, right? I mean, you you know, with with say a polycarbonate or you know, you see these polyester sandwich panels, they call them. Um good insulation levels, good light diffusion, but very short lifespans. And that's that's sort of the critical failing when you're into plastics. And and the scratching. Acrylic is the best of the bunch. There's no question. Acrylic is the best of the bunch. So where you might get 15 year, well, a polycarbonate, you're gonna get 10 years. That's like a Lexan type material. 10 years, maybe 15, like before you'll have to replace it because it's all yellow and it's and it's embrittled. Um, and and this the polyester sandwich panels, same thing, like that kind of 15-year sort of ballpark before it starts to just be too yellow, too brown for to to to continue. You know, unless it's like a storage facility where it's not occupied by humans regularly, in which case, have at it. It's a pr it's a perfect product for those kinds of scenarios. But but you want you don't want the t deterioration of the quality of the light that you get with plastics. Now, an acrylic though is 20 to 30 years. Right. So it's a much longer lifespan. Um but it w you you do get deterioration before uh that doesn't just doesn't happen in glass. Right. So if we can fill if we can really figure out the edge technology, which we're it's just improving all the time, right? It's the the failure of of of insulated glass units is is the spacer, it's the edge technology, what happens at the edges, which is true of almost everything in construction. What what happens at the joining points, what happens at the edges is is is what you know separates the men from the boys, as they used to say. Um so so you know those that has to improve as well, but it's happening. There's a lot of money going into it, a lot of research, and it's uh and and the progress has been quite rapid over these last, I don't know, say d two decades.

Georg Molzer 34:32

Because it's funny, I mean there there was awareness about the health of animals in animal shelters, you know, like in the full spectrum light, and it's it's slowly reaching how how humans also need it, you know. Like it's something that could be intuitively obvious, but seems like it's catching up that humans as well would benefit from it.

Joe Menchefski 34:53

I think we always we used to know. If you go back pr prior to uh I don't know, I'm not a historian and I've never really studied this. So this is a this is a Joe Manshewski guess again. But let's say before World War II or before like the real industrialization that took took place in you know the early 20th or early to middle 20th century, humans knew that we needed access to the outside world. We knew it. Uh our bodies needed sun, it needed, we needed fresh air, you know, we needed clean water. We all knew that. I think culturally it was built into every culture on earth. When, you know, we started to get wealthy and we started to have more sophisticated buildings and started spending more and more time in buildings. I think we forgot, right? And I think the rate at which we stopped caring about connectivity to the natural world accelerated when we started realizing how important energy was in the 1970s. And and uh we f we went hyper-focused on energy. And and by hyperfocusing on energy, we forgot about human health. Uh, we forgot that we need those connections. I I had a conversation recently. I was in I was in uh the US in uh Indiana. Do you guys have a metal like a metal building industry, a consequential metal building industry in Europe? Uh think of like the the uh big box stores that we have over here in North America where you know all the framing is metal and they this corrugated steel uh cladding, that sort of thing. Anyway, I was a producer of of these metal buildings that I was working with, and he said, look, the math is that the best building from an energy perspective is to not have any windows at all, right? Because then you can just insulate the hell out of the building envelope and the building roof and and and use the LED lights because LED lights are so cheap. So, like, there's no way you can make the argument that having natural light in the building is gonna be more efficient than than just using LEDs and and completely opaque building envelope elements. And I said, yeah, but if there's gonna be humans in it, you're gonna make them all sick. They're gonna be less productive, you're gonna have higher levels of uh um absenteeism, you're gonna have much lower levels of productivity. Uh and and you know, when you start doing the math on human performance productivity, compare that to energy savings, energy savings are a pittance, right? So dollars and cents, I mean, we have to, I'm not saying we we should lose our focus on energy. What I'm saying is don't forget that these are all buildings for humans.

Georg Molzer 37:51

Um Dave, you're muted.

Joe Menchefski 37:52

We lost Dave.

Smarter Design: Orientation & Passive Strategies. How better placement, modeling, and solar awareness can solve multiple problems.

Dave Wallace 37:53

I think we need to, thank you. Um uh the best hosts always are muted. So um, but is that a hint, Dave? No, well look, I I think I think it's really I think it's a really critical thing. It's about rebalancing all of these things. So yeah, you know, I mean it it's interesting because I was again talking to a company, um they're they're using solar collectors to get sunlight into a warehouse, like a big warehouse project in the Middle East. And that's fascinating to me that they've actually decided that you know an opaque uh walls is absolutely the right way to go, but they're also very conscious of getting sunlight into the building, so they they're gonna be using solar collectors. So that people are thinking about this. Um, just returning to kind of solutions. I mean, I guess one of the things that I'm beginning to realize, and by talking to people, but also by using tools like Shadow Map, and um, you know, it's really useful is to look at orientation of buildings. So, you know, at the moment when you do a project, I guess glass is one size fits all in terms of you you're doing a building and it's like you know, there's obviously going to be different designs for panes and things like that, but generally you'd be kind of thinking like we're going in with one solution, whereas you kind of alluded to it before. You know, if you've got a a north-facing aspect, you know, where you don't get a lot of direct sunlight, maybe that's the opportunity to kind of be bringing in you know, ray, you know, having a different glass solution, or you know, I I I'm pointing at my window here. This is actually um east facing, so it gets the morning sun, and then very quickly there's n it the sun passes. Now I would be prepared to um you know have more solar gain from that window to get that morning light coming in because I know that I'm not gonna get afternoon sun in it. So, you know, I guess the point is is there's more holistic thinking that perhaps needs to go into building design. And do you think that's something that the industry is kind of thinking about, or you know, is that still something that you you know is a bit bit complicated from a kind of or too technical from an architectural point of view to do?

Joe Menchefski 40:28

It's it's it is definitely being thought of. It it's at top of mind for um it's top of mind for most architects that I've spoken to, uh, which is a lot. Not and not just in the not just in the uh uh uh podcasting world, but like every day in in my work in daylighting, uh everybody's thinking about it all the time now, mercifully, like architects are for sure. Um so yeah, luckily, you know, peep people care about it. And so, you know, if you look at, you know, the historical techniques, pe people have been thinking about bringing light into buildings for a long, long time. I mean, there's there's like people talk about like the pyramids, and they, if you look at the design of some of the tunnels and you placed mirrors in certain locations in those tunnels, you could bring light deep into the pyramids, like you could bring natural light into it. And we know we look at structures. The way to bring light into spaces in a way that they don't end up being covered up with blinds to deal with the glare is to avoid direct sunlight. That has been the historical approach, right? So when you talk about glass on the north, that's why, right? You're never going to have direct beam sunlight on the north, on the north elevation. Um the shortcoming there is that all you're getting is reflected light, you know, the skylight that's reflected off the atmosphere, the light that's reflected off, you know, neighboring buildings or another mountain or something like that. The quantity just isn't there to have that light penetrate deep into a space. Now, in your home, Dave, is cool. Your home's not very deep, right? But when you get into so, you know, a school, a commercial building, a gymnasium, um, the light, you just don't have enough photons to penetrate deep into the space in order to, you know, truly illuminate it and get to uh you know that that sort of 500 lux number, which seems to be the magic number, uh the the level of illumination that's enough for us to work and and and you know do fine, you know, fine work and and and uh also to be healthy, apparently. Like the 500 is sort of the emerging number. Uh and again, somebody wants to come on and and and correct me on that, I I'd be happy. But I I had Jan Deneman from the Good Light Group on in Amsterdam uh not too long ago, and and you know, he was very confident of that of that 500 number. You're not going to get there with indirect sunlight, right? So when you when you start using all the you know the tunnels and the shelves and all those kinds of things that that are are built into that that come from historical or traditional methods, they were not created for the day when we have such large floor plates in our buildings. They just the techniques, the old techniques just don't cut it with such massive buildings like that that we have these days. Um so if if you're going to do effective daylighting, you kind of need direct sunlight. And this is where you know I work in diffusion because like I I need the direct sunlight in order to get the deep penetration. And when you run the model, when you run the models, you'll see it as plain as day, right? Um actually, uh K.org, I should introduce you to David Geisler Mora sometime. He's one of the the uh main creators of radiance, which is like a very, very sophisticated. Daylight modeling tool for interiors, right? Different, different from shadow map. It's almost exclusively about modeling the interiors and getting exact data, right? Um, because you need it for the HVAC designs, right? You need it for complementary lighting, like the the supplementary lighting from the artificial light. You need it like if you're going for Bream or Lead or Green Globes or one of these certifications. So so it it it you know it's been shown very, very clearly that without the direct light, it's hard to illuminate large spaces unless you have a really large glazed area, which is hard to do these days because of building codes to try to reduce energy. So that's you know, that's kind of the balancing act that that architects are dealing with these days.

Georg Molzer 44:51

You know it's super cool that there are people caring about it. And I think you know that the software is already there, but the software is not um yet integrating the the benefits of invisible light, you know. So I I mean it's it's the same physics basically, but it just needs to be enhanced in a way that that you know, like you have an understanding that this employee at this workspace also gets enough um invisible light spectrum to to stay healthy. And I think this is a paradigm shift that is currently really taking off. Like there's more and more awareness, and um, yeah, it's it's really just about doing it the right way. And I think it's I think it's fascinating, like given how how the human body requires full light spectrum, and then you think about what are the the possibilities to expose your body to full light spectrum. It's either like being outside or you're indoors and then you have a window or you have you have artificial light sources, and then you realize that the windows are blocking the the healthy light spectrums and and the artificial light sources are not providing them. I think the parallels are are really quite mind-blowing, and it's really just about a paradigm shift to have an understanding. Like you have um customers, humans, and users being aware of the necessity and then asking for it, and then the whole delivery chain eventually, this is what I hope, um, just plays along and and we we just enable healthier, happier, more productive, creative people.

Joe Menchefski 46:24

You should have Christoph Reinhard on your show sometime. He's at he's at Harvard, one of the leaders in uh, you know, sort of managing this balancing act, right? And and and you know, to to Dave's earlier question, that's that's what it is. Yeah, it it becomes a a a balancing act, an optimization exercise, and um and one where we try our very best, architects, designers try their very, very best to not sacrifice one aspect of building design in favor of another, which is what we've been doing for quite a while. For uh, I shouldn't say quite a while, but for the for you know the last couple of decades, building design has shifted to be all about energy efficiency and not about the multiple the multiple, multiple aspects of human health that are impacted by our uh impacted by our our our um our building design, you know, the the absence of light, the the absence of fresh air. Uh uh and you think about it. I mean, if you bring in lots of fresh air, that and and it's wintertime, you have to heat that air. That's inefficient from an energy perspective. But now we're talking about, okay, we're gonna we're gonna make sure that the people don't get any any fresh air because it's better for it's better for your uh for from an energy perspective, which is bonkers. But but but that is the trade-off that's that's happening.

Dave Wallace 47:52

Well, I mean you you I mean you look at like I mean there's a policy thing that needs to happen as well around this. You look at like in the UK, for instance, schools because of budget cuts and all the other bits and pieces have had to sell up all their playing fields. I mean, not all schools, but some schools have had to sell playing fields for housing and things like that to make money. What's the consequence of that is the kids don't get outside at break time. And and and so you then go, well, actually, you need to think about this in a very holistic way. You know, or you take the Middle East, like I don't know how you solve the problem of uh people in the Middle East not being able to get outside. I mean, I think different glasses would uh would solve the problem, but you know, maybe the solution is is to create you know, I don't know, conservatories with low, low kind of um blocking glass in them, which you then have to air condition. But but that's that balance it it sort of feels like this is I think within the kind of architectural community is something that they're really starting to wake up to. You know, Georg and I saw uh uh a presentation in which they had some a couple of artic architects from fosters, you know, talking about oh my god, we realised this sort of before we wouldn't have made some of the choices we've made in the past. So you can see that they're starting to wake up, but it it needs to kind of broaden out into being a a a sort of almost a a a kind of uh a political uh you know, a a something where policy actually starts to change. So people think about this in the kind of most rounded way.

Policy, Awareness & What Comes Next. Why this is bigger than architecture — and how change begins.

Georg Molzer 49:44

Yeah, I mean the the the first step is always awareness, you know, like there needs to be uh awareness of this issue, and and then I mean, we are engineers, right? There's always a a technical solution to these problems. Like you have a challenge and then you just optimize for it and you solve it. And and I think um ingenuity, I mean, like just recently, I think Joe, we talked about this as well, you know, like having glass where you have like an infrared filter that you can switch on and off. And and a few weeks after we talked, I I saw like a prototype from from some university where they basically invented this. And um, but of course, if nobody has even awareness that infrared is is crucial, and I think it's still the minority of people who have some awareness how how important it is, then nobody asked for it, it's not gonna happen. But as soon as more people have an understanding about it, eventually it's gonna happen. So it's it's it's also our job to to spread awareness and and yeah, inform the people that this is actually an issue.

Joe Menchefski 50:42

Absolutely. And you know, I love what you guys have done with Shadow Map. I it it's the way I see it, it's it's the democratization of the ability to truly understand. I mean, these radiance like radiance is is incredibly complicated. It's literally a ray tracer. It like traces the path of every single photon and then accumulates it, and it's like it's a very, very sophisticated tool, and there's a small number of people who are really, really, really good at it. With Shadow Map, you know, it it's an incredible democratization that more people, you know, more sort of laymen or people who don't have a tremendous amount of expertise can still, without spending a bloody fortune, can still understand the movement of the sun and how it's going to affect the design of their home or their building or their garden or or or you know their recreational facility. It it is a beautiful, beautiful opportunity for everybody to understand, you know, that it's really doable. It is possible to bring in the light to provide the views if we take the time and think about it and think about more than just the energy calculation, right? You doubt you have to do both, but for a long time we've just been doing the math and and for forgetting about the human component.

Georg Molzer 52:06

Yeah, we do believe in in win-win-win situations here. Absolutely. It's impossible to design a home in a way that you have enough light, you have uh better health, you still save energy. I mean, we had this case with a civil engineer which was also on our podcast, and and just by rotating a house by 30 degrees, they saved significant amounts of of money in cooling, heating, um, at the same time making the home brighter. It's really like it is as you said, like making this very approachable and simple, you enable more and more people to even ask questions and and like confront the architects. So, why didn't you think about it? Sometimes the architects are not thinking about it, but if if the buyer plays around with it easily and and sees like, hey man, what's up? Like, why are you not uh solving this in the best way? It's just yeah, as I say, it's a it's a democratization tool.

Joe Menchefski 53:00

You get the orientation right, you get the placement of the windows right, you get the size of the windows right. Um, and you can you can really manage your house passively. I I'll give you like a very personal example. Uh my home, uh I my home in the city is is it's relatively small. I live in Canada, so like this time of year, there's no sort of passive opportunities or it's minimal, right? I just have to keep everything closed because it's, you know, it could be minus 20 tonight. Um but in the spring and in the fall, you know, I can open my, you know, open my windows at the, you know, in the evening and and bring in lots of fresh air and cool the house so that it's very nice for sleeping, you know, and close them in the morning and and you know, open any sort of curtains to make sure that I maximize solar heat gain so that the house is nice and warm during the day. I can I become sort of like a uh uh you know, like an HVAC, my own HVAC system, uh or like true passive design. I I I don't automate it, but I kind of like doing it myself. I like thinking about when I'm opening, closing my windows, when I'm opening and closing, you know, any sort of any sort of blind or curtain because I'm I'm it connects me to what's happening outside. Uh and I and I like doing it, and I can save a tremendous amount of energy and make my house healthier because I'm thinking about these things. And it's not like I'm spending, you know, two hours a day. I'm talking like five minutes in the morning and five minutes in the evening to open a you know, open and close the right windows. Um, but you know, if you truly understand what's happening with the sun and the position of the sun and uh, you know, and inside-outside temperatures, it's not really all that hard to do. I don't ever have to do any math. I just, you know, go by the feel of how the uh how my house feels and how the different rooms feel at different times.

Dave Wallace 54:59

I love that because you know, it's one of the things, you know, underlying all of this is stuff that we all know subconsciously, or slightly above subconsciously, we all know that we need a relationship with the sun. Otherwise, people wouldn't flock to the beaches in the summer, you know, or we wouldn't, you know, we wouldn't like the every Brit sort of as soon as the sun comes out, puts their shorts on and you know, rushes out in t-shirts. And so we all subconsciously, or just above subconsciously, know about this. So I think a lot of it is just listening to yourself a bit more and saying, Well, what opportunity. It's like I someone it like uh they advise what one of their small pieces of advice is when you're in a car, like in a if it's a sunny day, even if it's cold outside, just crack a window. So you've got a little bit of sunlight, you know. And I'm like, Yeah, well that's so I've started doing that, and I find that you know I look forward to car journeys a lot more now. So there's all these small things that you can kind of do which incrementally would make a difference, whilst the industry is kind of getting its head round what to do and how to do it. And um, you know, I I'm I think it's it it's fascinating. I mean, one of the things that would be brilliant, Joe, is perhaps to revisit the whole topic in 12 months' time and see where you think the industry has got to.

Joe Menchefski 56:24

I'd love that, yeah.

Dave Wallace 56:25

Because I think you know, what what you've said is is we're on the cusp of it now in terms of some of the some of the some of the uh differences that are gonna kind of be made from a product point of view. So it'd be good to catch up in 12 months' time and see what's going on.

Joe Menchefski 56:41

I'd love that, yes, absolutely.

Dave Wallace 56:44

Fantastic. Well, listen, we're we're almost at an hour, so um you know, we're we're sort of straying into uh Lex Friedman territory around uh the time on the podcast. So, you know, I I think for me that's been fascinating. I've learned a huge amount. Um I'm now gonna go and bore my family with a tales of why we need um different glass in our windows. I've already been through the whole incandescent bulb thing with them. So they'll roll their eyes and then gradually accept it. So yeah.

Joe Menchefski 57:15

Just just put a couple of incandescent bulbs in like one lamp, one lamp in every room. Or uh we went through this process already.

Dave Wallace 57:23

Yeah, yeah, yeah.

Georg Molzer 57:24

We we last season was changing the light sources, next season is about changing all the windows, I guess.

Final Thoughts & Looking Ahead

Dave Wallace 57:31

Well, it is it, I mean, uh it's interesting because we also I we discovered or heard about green light, sort of they don't really know why, but green light is an analgesic. So if you have migraines, shining a green light in your eyes is actually a pretty good way of I think they say 60% of people, when they kind of did some research with migraines, it cleared it up totally. So I know my wife gets migraines. In our kitchen, we have a green light which is on most of the time, and she's not had a migraine. So, I mean, what what on earth is going on there? You know, who knows? But somebody does.

Joe Menchefski 58:11

Well, exactly.

Dave Wallace 58:12

Somebody does, you know. So anyway, but thank you so much for coming. Um and you know, it's been a fascinating conversation. As I say, it'd be great to catch up in 12 months' time.

Joe Menchefski 58:23

I always love talking to you guys, so anytime. 100%. Thank you, Joe. My pleasure. Take care.