WEBVTT 00:00:00.000 --> 00:00:03.419 Okay, I want to start today with a number, and 00:00:03.419 --> 00:00:06.299 honestly, it's a number that completely stopped 00:00:06.299 --> 00:00:08.580 me in my tracks when I was reading through the 00:00:08.580 --> 00:00:11.580 stack of research for this deep dive. I have 00:00:11.580 --> 00:00:12.859 a feeling I know which one you're talking about. 00:00:12.980 --> 00:00:14.640 I actually had to double check it because it 00:00:14.640 --> 00:00:16.899 felt, well, it felt wrong. It's the big one. 00:00:17.320 --> 00:00:22.079 38%. Right. 38 % of total global greenhouse gas 00:00:22.079 --> 00:00:24.899 emissions come from construction. From buildings. 00:00:25.079 --> 00:00:28.539 From buildings. It is. It's staggering. It is, 00:00:28.539 --> 00:00:30.859 isn't it? When you really let that sink in. It 00:00:30.859 --> 00:00:33.740 is. Because I think most of us, when we visualize 00:00:33.740 --> 00:00:36.960 climate change, we have a very specific set of, 00:00:36.960 --> 00:00:39.539 like, stock images in our heads. Oh, for sure. 00:00:39.740 --> 00:00:41.880 We think about bumper -to -bumper traffic on 00:00:41.880 --> 00:00:44.700 the 405. Yep. The smokestacks. The smokestacks. 00:00:44.700 --> 00:00:47.240 We think about airplanes taking off. These massive 00:00:47.240 --> 00:00:50.359 facts. factories belching out gray clouds, but 00:00:50.359 --> 00:00:53.320 we rarely look at the ceiling above us or the 00:00:53.320 --> 00:00:55.079 floor beneath our feet. That's what some of the 00:00:55.079 --> 00:00:57.219 research calls the invisible villain paradox. 00:00:57.579 --> 00:01:00.880 The invisible villain. I like that. We notice 00:01:00.880 --> 00:01:03.700 the things that move. We notice the things that 00:01:03.700 --> 00:01:07.140 make noise. Cars, planes, factories, they're 00:01:07.140 --> 00:01:10.599 all active. They're dynamic. Exactly. But buildings, 00:01:10.760 --> 00:01:13.799 they just they sit there. They feel benign. They 00:01:13.799 --> 00:01:16.920 feel safe. Static. But the reality is that the 00:01:16.920 --> 00:01:20.099 built environment is the single largest contributor 00:01:20.099 --> 00:01:22.859 to the climate crisis. And if you want to zoom 00:01:22.859 --> 00:01:26.400 in on a specific culprit within that 38 percent 00:01:26.400 --> 00:01:30.260 sort of the boss battle of this problem, it's 00:01:30.260 --> 00:01:32.540 cement. Cement is the heavy hitter. No question. 00:01:33.000 --> 00:01:35.219 Just cement production alone is responsible for 00:01:35.219 --> 00:01:37.780 8 % of all global emissions. Okay. Can we just 00:01:37.780 --> 00:01:41.040 contextualize that? Because 8 % sounds like a 00:01:41.040 --> 00:01:44.079 small slice of a pie, but in global terms. In 00:01:44.079 --> 00:01:46.140 global terms, it's a superpower. The superpower. 00:01:46.260 --> 00:01:50.540 Yes. If cement were a country, it would be the 00:01:50.540 --> 00:01:52.620 third largest polluter in the world. You're kidding. 00:01:52.900 --> 00:01:55.420 No. Right behind China and the United States. 00:01:55.560 --> 00:01:57.640 It would emit more than India. More than India. 00:01:57.700 --> 00:01:59.840 It would emit more than the entire European Union. 00:02:00.219 --> 00:02:02.939 That is wild. We are talking about the gray glue 00:02:02.939 --> 00:02:06.099 that holds our sidewalks and skyscrapers together, 00:02:06.239 --> 00:02:08.900 and it's polluting more than entire continents. 00:02:09.120 --> 00:02:11.139 That's the one. So naturally, we are doing a 00:02:11.139 --> 00:02:13.139 deep dive today on sustainable architecture. 00:02:13.340 --> 00:02:15.180 But I want to be really clear right off the bat, 00:02:15.240 --> 00:02:16.960 because I know what happens when people hear 00:02:16.960 --> 00:02:19.060 that phrase. They tune out. They tune out. They 00:02:19.060 --> 00:02:22.120 think this is going to be an hour of scolding 00:02:22.120 --> 00:02:25.139 them to change their light bulbs to LEDs or telling 00:02:25.139 --> 00:02:28.080 them to slap a solar panel on the roof and call 00:02:28.080 --> 00:02:30.479 it a day. Please no. That is the most surface 00:02:30.479 --> 00:02:32.319 level stuff. We're going so much deeper than 00:02:32.319 --> 00:02:35.300 that. Exactly. The mission of this deep dive 00:02:35.300 --> 00:02:38.879 is to figure out how we move from those scary 00:02:38.879 --> 00:02:42.520 numbers, that 38%, to a way of building that 00:02:42.520 --> 00:02:45.560 actually heals the environment rather than actively 00:02:45.560 --> 00:02:48.240 hurting it. Right. From extractive to regenerative. 00:02:48.360 --> 00:02:50.919 And the research you brought in, It's surprisingly 00:02:50.919 --> 00:02:54.039 high tech, but also strangely ancient. It is. 00:02:54.099 --> 00:02:56.539 It's this amazing blend. We're going to be talking 00:02:56.539 --> 00:02:59.199 about buildings that cool themselves using the 00:02:59.199 --> 00:03:01.819 coldness of outer space. Which sounds like science 00:03:01.819 --> 00:03:04.460 fiction. Literal rocket science physics. Yeah. 00:03:05.080 --> 00:03:08.020 But we're also going to talk about why 17th century 00:03:08.020 --> 00:03:11.259 settlers probably knew more about energy efficiency 00:03:11.259 --> 00:03:15.360 than most modern architects. Okay, so. Let's 00:03:15.360 --> 00:03:17.199 define our terms before we get into the weeds. 00:03:17.379 --> 00:03:20.819 When we say sustainable architecture, what are 00:03:20.819 --> 00:03:22.979 we actually talking about? Because I feel like 00:03:22.979 --> 00:03:25.699 that term gets slapped on anything with a potted 00:03:25.699 --> 00:03:28.759 plant in the lobby. It does. Greenwashing is 00:03:28.759 --> 00:03:31.080 a huge issue in the industry. Right. You put 00:03:31.080 --> 00:03:32.860 a bike rack out front and suddenly the building 00:03:32.860 --> 00:03:35.560 is eco -friendly. Oh. But formally, when we talk 00:03:35.560 --> 00:03:36.979 about sustainable architecture, we're talking 00:03:36.979 --> 00:03:39.819 about minimizing negative environmental impact. 00:03:40.159 --> 00:03:42.199 Okay. And you do that through a very specific 00:03:42.199 --> 00:03:46.199 philosophy. Efficiency and moderation. Moderation. 00:03:46.199 --> 00:03:48.080 That's a word you don't hear much in construction. 00:03:48.280 --> 00:03:50.400 Exactly. Moderation in the use of materials, 00:03:50.539 --> 00:03:53.139 moderation in energy consumption, and moderation 00:03:53.139 --> 00:03:55.379 in the development space itself. That sounds 00:03:55.379 --> 00:03:58.020 almost philosophical, like a diet for buildings. 00:03:58.099 --> 00:04:00.800 It is philosophical. And the best versions of 00:04:00.800 --> 00:04:03.659 this go beyond just doing less bad. The gold 00:04:03.659 --> 00:04:06.000 standard is what we call regenerative architecture 00:04:06.000 --> 00:04:09.360 buildings that focus on social sustainability 00:04:09.360 --> 00:04:12.800 and ecological conservation. So not just less 00:04:12.800 --> 00:04:15.819 harm, but actually doing good. Precisely. The 00:04:15.819 --> 00:04:18.420 goal is to ensure that our use of resources today 00:04:18.420 --> 00:04:21.120 doesn't make it impossible for future societies 00:04:21.120 --> 00:04:24.519 to survive. It's about being a good ancestor. 00:04:24.759 --> 00:04:26.720 Being a good ancestor. I like that. Okay, so 00:04:26.720 --> 00:04:29.040 we've got a big roadmap today. We're going to 00:04:29.040 --> 00:04:31.699 unpack the history of this movement, look at 00:04:31.699 --> 00:04:33.740 the invisible carbon nobody talks about, break 00:04:33.740 --> 00:04:36.240 down the physics of free energy, and then get 00:04:36.240 --> 00:04:38.579 into the really sci -fi stuff like lab -grown 00:04:38.579 --> 00:04:40.829 wood. It's going to be a journey. All right. 00:04:40.850 --> 00:04:42.769 Let's start with the philosophy. Because looking 00:04:42.769 --> 00:04:44.889 at the research, it seems like there was a massive 00:04:44.889 --> 00:04:48.170 shift in how we even view green buildings. For 00:04:48.170 --> 00:04:50.449 a long time, it felt like it was just an engineering 00:04:50.449 --> 00:04:52.670 problem. That's a very common misconception. 00:04:52.889 --> 00:04:55.889 And frankly, it was the dominant view for most 00:04:55.889 --> 00:04:58.089 of the late 20th century. Just about the gadgets. 00:04:58.430 --> 00:05:01.129 It was all about the gadgets. The term sustainability 00:05:01.129 --> 00:05:03.529 was viewed almost exclusively through the lens 00:05:03.529 --> 00:05:05.529 of building technology. It was about the machinery. 00:05:06.029 --> 00:05:08.750 How efficient is this boiler? Exactly. What is 00:05:08.750 --> 00:05:12.230 the R -value of this insulation? Can we invent 00:05:12.230 --> 00:05:14.649 a better window? It was a technical problem to 00:05:14.649 --> 00:05:16.629 be solved with more tech. Which makes sense. 00:05:16.649 --> 00:05:20.089 We love gadgets. We do. But scholars are now 00:05:20.089 --> 00:05:22.970 shifting from that narrow technical focus to 00:05:22.970 --> 00:05:25.529 a much broader cultural framework. What does 00:05:25.529 --> 00:05:27.730 that mean, a cultural framework? They're looking 00:05:27.730 --> 00:05:30.550 at the human interrelationship with nature. It's 00:05:30.550 --> 00:05:33.170 not just how do we plug this heat leak? It's 00:05:33.170 --> 00:05:35.649 how have humans related to their environment 00:05:35.649 --> 00:05:38.730 over the last 10 ,000 years? And, you know, where 00:05:38.730 --> 00:05:41.290 did we lose the plot? And this actually ties 00:05:41.290 --> 00:05:43.750 back to a really interesting historical nugget 00:05:43.750 --> 00:05:45.990 you found involving Princeton University of all 00:05:45.990 --> 00:05:48.730 places. It does. This is a fascinating bit of 00:05:48.730 --> 00:05:53.240 like academic drama. In the 1940s and 50s, the 00:05:53.240 --> 00:05:55.199 Princeton School of Architecture played a pivotal 00:05:55.199 --> 00:05:57.980 role in reintroducing history into design training. 00:05:58.139 --> 00:06:00.399 Wait, reintroducing? Had they banned history? 00:06:00.620 --> 00:06:03.199 In a way, yes. You have to understand the mindset 00:06:03.199 --> 00:06:05.439 of modernism in the early 20th century. Think 00:06:05.439 --> 00:06:07.920 about Le Corbusier, the Bauhaus, the international 00:06:07.920 --> 00:06:10.819 style. These were people coming out of the trauma 00:06:10.819 --> 00:06:14.139 of World War I. They wanted a clean break with 00:06:14.139 --> 00:06:16.899 the past. Right, the past was messy. The past 00:06:16.899 --> 00:06:20.529 was messy, monarchical, and inefficient. They 00:06:20.529 --> 00:06:22.870 wanted a new world based on the machine. The 00:06:22.870 --> 00:06:26.709 famous machine for living. Exactly. So they rejected 00:06:26.709 --> 00:06:29.589 history. They literally stopped teaching how 00:06:29.589 --> 00:06:32.069 to build traditional roofs or thick walls. They 00:06:32.069 --> 00:06:35.449 built glass boxes that looked the same whether 00:06:35.449 --> 00:06:38.189 they were in snowy Moscow or sunny Los Angeles. 00:06:38.569 --> 00:06:41.949 Which sounds cool aesthetically, I guess, but 00:06:41.949 --> 00:06:43.850 practically? Practically, it was an environmental 00:06:43.850 --> 00:06:46.829 disaster. An oven or a freezer? A glass box in 00:06:46.829 --> 00:06:48.930 the desert is an oven. A glass box in Moscow 00:06:48.930 --> 00:06:51.000 is a freezer. The only way those buildings were 00:06:51.000 --> 00:06:52.920 habitable was because we had invented massive 00:06:52.920 --> 00:06:55.160 air conditioning and heating systems powered 00:06:55.160 --> 00:06:57.459 by cheap fossil fuels. So I used brute force 00:06:57.459 --> 00:07:00.439 energy to fight nature. We used brute force to 00:07:00.439 --> 00:07:02.980 correct a bad design. So Princeton bringing history 00:07:02.980 --> 00:07:05.579 back wasn't just about nostalgia for old buildings. 00:07:05.959 --> 00:07:09.899 Not at all. By the 1970s, you had Ph .D. programs 00:07:09.899 --> 00:07:12.720 popping up specifically for architectural history, 00:07:12.959 --> 00:07:15.600 founded by people like Anthony Vidler at Princeton 00:07:15.600 --> 00:07:19.860 and Stanford Anderson at MIT. This intellectual 00:07:19.860 --> 00:07:22.639 groundwork helped us realize that pre -modern 00:07:22.639 --> 00:07:25.300 builders weren't primitive. Right. They were 00:07:25.300 --> 00:07:28.060 geniuses of adaptation. They knew how to survive 00:07:28.060 --> 00:07:31.120 without the brute force of cheap oil. So we're 00:07:31.120 --> 00:07:32.959 looking back to move forward. But before we get 00:07:32.959 --> 00:07:34.699 to the solutions, we have to talk about this 00:07:34.699 --> 00:07:37.420 thing you called the carbon trap. You mentioned 00:07:37.420 --> 00:07:39.720 earlier that we focus on the wrong things. We 00:07:39.720 --> 00:07:42.480 do. We have a massive blind spot. We need to 00:07:42.480 --> 00:07:45.279 distinguish between operational carbon and embodied 00:07:45.279 --> 00:07:48.170 carbon. Okay, let's unpack that. Operational 00:07:48.170 --> 00:07:51.410 carbon sounds like the utility bill, right? Basically, 00:07:51.410 --> 00:07:53.990 yes. Operational carbon is the energy used to 00:07:53.990 --> 00:07:56.410 run the house. The electricity for your lights, 00:07:56.529 --> 00:07:59.089 the gas for your water heater, the power for 00:07:59.089 --> 00:08:01.389 your AC. The day -to -day stuff. The day -to 00:08:01.389 --> 00:08:03.930 -day. And we have gotten very good at talking 00:08:03.930 --> 00:08:06.490 about this. Everyone knows what an LED bulb is. 00:08:06.870 --> 00:08:08.949 Everyone looks for the Energy Star sticker on 00:08:08.949 --> 00:08:10.790 their fridge. Right. If I leave the lights on, 00:08:10.910 --> 00:08:13.750 I feel guilty. That's operational carbon guilt. 00:08:13.870 --> 00:08:17.079 Exactly. But embodied carbon. That's the ghost 00:08:17.079 --> 00:08:19.300 in the machine. Okay. Embodied carbon is the 00:08:19.300 --> 00:08:21.699 energy used to make the house. To build it. To 00:08:21.699 --> 00:08:24.379 build it. It's the mining of the ore, the smelting 00:08:24.379 --> 00:08:26.939 of the steel, the crushing of the limestone for 00:08:26.939 --> 00:08:29.779 cement, the transportation of those heavy materials 00:08:29.779 --> 00:08:32.440 to the site, and the actual construction. So 00:08:32.440 --> 00:08:34.639 it's the backpack of emissions the house puts 00:08:34.639 --> 00:08:37.399 on before anyone even moves in? That is a perfect 00:08:37.399 --> 00:08:40.460 analogy. Every single building starts its life 00:08:40.460 --> 00:08:43.360 with a carbon debt. And here's the kicker. For 00:08:43.360 --> 00:08:46.669 a standard new building, That backpack of embodied 00:08:46.669 --> 00:08:49.909 carbon accounts for about half of its total lifetime 00:08:49.909 --> 00:08:52.830 emissions. Half. Half. So all the effort we spend 00:08:52.830 --> 00:08:55.129 on efficient light bulbs and appliances only 00:08:55.129 --> 00:08:58.259 addresses half the problem. At best. And we have 00:08:58.259 --> 00:09:00.240 almost no regulations for it. We have strict 00:09:00.240 --> 00:09:02.200 codes for how much insulation you need. That's 00:09:02.200 --> 00:09:04.840 operational. But we have almost no rules about 00:09:04.840 --> 00:09:07.000 how much carbon you can spew into the atmosphere 00:09:07.000 --> 00:09:09.399 to make the steel beams holding the roof up. 00:09:09.460 --> 00:09:11.480 And going back to your stat about cement, that's 00:09:11.480 --> 00:09:14.259 all embodied carbon. It is. Concrete is the most 00:09:14.259 --> 00:09:17.039 consumed substance on Earth after water. And 00:09:17.039 --> 00:09:20.070 making it is incredibly dirty. You have to heat 00:09:20.070 --> 00:09:23.570 limestone to 1 ,400 degrees Celsius. That requires 00:09:23.570 --> 00:09:25.830 massive amounts of fossil fuel. Okay, so I have 00:09:25.830 --> 00:09:28.110 to ask the obvious question then. If concrete 00:09:28.110 --> 00:09:31.029 is so bad, if it's the superpower of pollution, 00:09:31.389 --> 00:09:34.110 why do we use so much of it? Are architects just 00:09:34.110 --> 00:09:37.909 lazy? That's the tough part. It's not laziness. 00:09:38.389 --> 00:09:42.750 Concrete is. It's miraculous stuff. How so? It's 00:09:42.750 --> 00:09:45.370 liquid stone. You can pour it into any shape. 00:09:45.429 --> 00:09:48.009 It dries rock hard. It doesn't rot. Termites 00:09:48.009 --> 00:09:50.529 don't eat it. relatively cheap. It's a silver 00:09:50.529 --> 00:09:53.929 bullet material. It is. And replacing it is incredibly 00:09:53.929 --> 00:09:56.549 difficult because nothing else does exactly what 00:09:56.549 --> 00:09:58.529 concrete does at that price point. So we're hooked 00:09:58.529 --> 00:10:00.389 on it. We are addicted to it. Yeah. But if we 00:10:00.389 --> 00:10:02.590 ignore embodied carbon, we're missing the boat 00:10:02.590 --> 00:10:04.990 entirely. You can build a net zero house that 00:10:04.990 --> 00:10:07.539 uses zero electricity. But if you poured 500 00:10:07.539 --> 00:10:09.980 tons of concrete to build it, you front loaded 00:10:09.980 --> 00:10:12.580 so much damage. That it might take 50 years of 00:10:12.580 --> 00:10:15.039 efficiency just to pay back that initial debt. 00:10:15.220 --> 00:10:17.820 If ever. So we need to build smarter, not just 00:10:17.820 --> 00:10:20.220 run smarter. And that leads us perfectly into 00:10:20.220 --> 00:10:22.779 the idea of passive design. This is my favorite 00:10:22.779 --> 00:10:25.059 topic. I know it is. And this is basically the 00:10:25.059 --> 00:10:28.519 free energy we teased in the intro. So lay it 00:10:28.519 --> 00:10:30.980 out for us. Passive versus active. What's the 00:10:30.980 --> 00:10:33.220 difference? It's a simple definition. Active 00:10:33.220 --> 00:10:36.879 strategies use motors, pumps. fans, and plugs. 00:10:37.240 --> 00:10:40.320 They need an external power source. Right. Passive 00:10:40.320 --> 00:10:42.179 strategies mean the building itself does the 00:10:42.179 --> 00:10:44.799 work just by sitting there. It relies on physics, 00:10:45.059 --> 00:10:48.600 geometry, and the laws of thermodynamics. And 00:10:48.600 --> 00:10:51.039 geometry is surprisingly important here. The 00:10:51.039 --> 00:10:53.519 research talked about the surface area to volume 00:10:53.519 --> 00:10:57.019 ratio. This is crucial. And to explain it, I 00:10:57.019 --> 00:10:58.980 want you to think about a cup of coffee. I am 00:10:58.980 --> 00:11:01.460 always thinking about coffee. Good. So imagine 00:11:01.460 --> 00:11:04.580 you pour hot coffee into a tall standard bug. 00:11:05.000 --> 00:11:06.960 And then you pour the same amount of hot coffee 00:11:06.960 --> 00:11:09.620 onto a large flat dinner plate. Which one gets 00:11:09.620 --> 00:11:12.820 cold first? The plate. Instantly. Why? Because, 00:11:12.940 --> 00:11:14.940 well, it's spread out. There's more coffee touching 00:11:14.940 --> 00:11:17.580 the air. Exactly. The skin of the liquid is where 00:11:17.580 --> 00:11:20.340 the heat escapes. The plate has a massive surface 00:11:20.340 --> 00:11:22.539 area compared to the volume of coffee. So more 00:11:22.539 --> 00:11:25.940 skin, more heat loss. Right. The mug is compact. 00:11:26.259 --> 00:11:29.039 It has a low surface area relative to its volume. 00:11:29.829 --> 00:11:32.389 Buildings work the exact same way. So if I build 00:11:32.389 --> 00:11:35.090 a sprawling house with wings jutting out everywhere, 00:11:35.330 --> 00:11:37.830 what people call organic? You are building a 00:11:37.830 --> 00:11:40.549 dinner plate. Wow. You are maximizing the skin 00:11:40.549 --> 00:11:42.850 of the building, which means you are maximizing 00:11:42.850 --> 00:11:45.129 heat loss in the winter and heat gain in the 00:11:45.129 --> 00:11:48.169 summer. From an energy perspective, those organic 00:11:48.169 --> 00:11:51.250 sprawling shapes are often a disaster. So what's 00:11:51.250 --> 00:11:53.629 the mug of architecture? What's the ideal shape? 00:11:53.830 --> 00:11:56.320 The cube. Or the sphere, technically, but spheres 00:11:56.320 --> 00:11:58.919 are hard to furnish. Hard to hang pictures. Right. 00:11:58.980 --> 00:12:02.360 So a compact, multi -story box is the most efficient 00:12:02.360 --> 00:12:05.879 shape. And this brings us back to history. The 00:12:05.879 --> 00:12:08.120 research mentions the traditional American salt 00:12:08.120 --> 00:12:10.929 box, or colonial design. I always thought those 00:12:10.929 --> 00:12:12.809 houses looked that way just because of style. 00:12:13.049 --> 00:12:15.809 Like, oh, it's 1750. This is the fashion. That 00:12:15.809 --> 00:12:18.009 is the modernist trap again. Yeah. We assume 00:12:18.009 --> 00:12:19.870 they made aesthetic choices. They didn't. They 00:12:19.870 --> 00:12:22.110 made survival choices. That's a huge shift in 00:12:22.110 --> 00:12:25.649 thinking. The saltbox shaped two stories. Compact, 00:12:25.649 --> 00:12:28.909 boxy was the mug. It kept the heat in around 00:12:28.909 --> 00:12:31.210 the central fireplace. And what about the roof 00:12:31.210 --> 00:12:34.269 on those? The saltbox has that distinct, long, 00:12:34.289 --> 00:12:36.889 sloping roof that goes almost to the ground on 00:12:36.889 --> 00:12:40.000 the back. That's not style. That is aerodynamics 00:12:40.000 --> 00:12:41.820 and shielding. It's aerodynamics. You almost 00:12:41.820 --> 00:12:44.820 always point that low sloping roof towards the 00:12:44.820 --> 00:12:47.679 north. Why north? Because in New England, that's 00:12:47.679 --> 00:12:50.500 where the brutal winter winds come from. The 00:12:50.500 --> 00:12:52.779 roof acts like a shield, deflecting the wind 00:12:52.779 --> 00:12:57.000 up and over the house. Meanwhile, the flat two 00:12:57.000 --> 00:13:00.159 -story side with most of the windows faces south. 00:13:00.360 --> 00:13:03.259 To catch the sun? Precisely. It is a passive 00:13:03.259 --> 00:13:05.940 solar machine disguised as a house. So let's 00:13:05.940 --> 00:13:08.600 talk about catching the sun. Because facing south 00:13:08.600 --> 00:13:11.399 feels like the oldest rule in the book, but the 00:13:11.399 --> 00:13:14.039 physics of it are pretty specific. It's all about 00:13:14.039 --> 00:13:16.600 solar gain. In the northern hemisphere, the sun 00:13:16.600 --> 00:13:18.960 is always in the southern part of the sky. In 00:13:18.960 --> 00:13:21.000 the winter, it's low on the horizon. And in the 00:13:21.000 --> 00:13:23.639 summer, it's high overhead. Exactly. And you 00:13:23.639 --> 00:13:25.960 want to capture that low winter sun to heat your 00:13:25.960 --> 00:13:28.080 home for free. But windows are the weak point, 00:13:28.120 --> 00:13:30.059 right? Even a good window is basically a hole 00:13:30.059 --> 00:13:33.299 in your insulation. Generally, yes. Glass is 00:13:33.299 --> 00:13:36.240 a poor insulator compared to a solid wall. That's 00:13:36.240 --> 00:13:38.740 why we've developed smart windows, double or 00:13:38.740 --> 00:13:41.000 triple glazing. Which just means layers of glass. 00:13:41.220 --> 00:13:44.159 Layers of glass with an inert gas -like argon 00:13:44.159 --> 00:13:47.919 sandwiched in between. The gas acts as an insulator, 00:13:48.120 --> 00:13:52.139 but the real magic is the low E coating. Low 00:13:52.139 --> 00:13:55.460 emissivity. Right. It's a microscopically thin 00:13:55.460 --> 00:13:58.440 layer of metal oxide on the glass. It's transparent 00:13:58.440 --> 00:14:00.559 to visible light so you can see through it, but 00:14:00.559 --> 00:14:02.919 it acts like a mirror to infrared heat. So it 00:14:02.919 --> 00:14:05.529 filters the heat? It does. In the winter, it 00:14:05.529 --> 00:14:07.370 reflects the heat inside your house back into 00:14:07.370 --> 00:14:09.509 the room so it can't escape. In the summer, it 00:14:09.509 --> 00:14:11.610 reflects the solar heat outside back away from 00:14:11.610 --> 00:14:14.450 the house. It's a one -way heat door. But here 00:14:14.450 --> 00:14:16.950 is the problem I see. If I have a wall of glass 00:14:16.950 --> 00:14:19.990 facing south to catch the winter sun, am I not 00:14:19.990 --> 00:14:22.110 going to roast like a chicken in July? That is 00:14:22.110 --> 00:14:23.970 the challenge. If you don't manage it, yes, you 00:14:23.970 --> 00:14:26.190 will cook. So how do you manage it? This is where 00:14:26.190 --> 00:14:28.629 shading comes in. And again, the best technology 00:14:28.629 --> 00:14:31.529 for this isn't a microchip. It's a tree. A specific 00:14:31.529 --> 00:14:34.059 kind of tree. A deciduous tree. The wolves that 00:14:34.059 --> 00:14:36.220 lose their leaves in the fall. So walk me through 00:14:36.220 --> 00:14:39.259 the cereal cycle here. Okay. You plant a big 00:14:39.259 --> 00:14:41.960 oak or a maple on the south side of your house. 00:14:42.259 --> 00:14:46.320 In June, the sun is high and brutal, but the 00:14:46.320 --> 00:14:49.639 tree is full of leaves. So it's like a big green 00:14:49.639 --> 00:14:52.399 umbrella. It blocks the sun shading your windows. 00:14:52.779 --> 00:14:56.340 Your house stays cool. It's free AC. Okay. Then 00:14:56.340 --> 00:14:59.179 comes November. It gets cold. You want that heat. 00:14:59.519 --> 00:15:02.740 What happens? The tree drops its leaves. And 00:15:02.740 --> 00:15:04.799 the sun comes through. Suddenly the branches 00:15:04.799 --> 00:15:07.360 are bare and the low winter sunlight streams 00:15:07.360 --> 00:15:09.539 right through the gaps, hitting your windows 00:15:09.539 --> 00:15:12.240 and heating your floors. It's an automatic climate 00:15:12.240 --> 00:15:15.139 control system powered by photosynthesis. It 00:15:15.139 --> 00:15:17.700 really is. And if you can't plant a tree, you 00:15:17.700 --> 00:15:20.139 can use things called light shelves or louvers. 00:15:20.539 --> 00:15:22.659 The research mentioned light shelves. How do 00:15:22.659 --> 00:15:24.840 those work? They sound like furniture. Think 00:15:24.840 --> 00:15:26.879 of a horizontal shelf sticking out from the middle 00:15:26.879 --> 00:15:29.620 of your window. Okay. It physically blocks the 00:15:29.620 --> 00:15:31.679 high summer sun from hitting the lower part of 00:15:31.679 --> 00:15:34.220 your window. But the top of the shelf is reflective. 00:15:34.399 --> 00:15:37.279 It bounces the sunlight up onto the ceiling of 00:15:37.279 --> 00:15:39.360 the room. Oh, so you get the light but not the 00:15:39.360 --> 00:15:42.019 direct heat beam. Exactly. It throws the light 00:15:42.019 --> 00:15:43.700 deep into the building so you don't need electric 00:15:43.700 --> 00:15:46.759 bulbs. But it keeps the glare and the heat gain 00:15:46.759 --> 00:15:49.639 down. It's simple geometry, but it changes the 00:15:49.639 --> 00:15:52.159 feel of a room completely. Okay, another term 00:15:52.159 --> 00:15:56.230 in the passive section was thermal mass. This 00:15:56.230 --> 00:15:58.610 sounds heavy. It literally is. Thermal mass refers 00:15:58.610 --> 00:16:02.769 to heavy, dense materials like masonry, stone, 00:16:02.909 --> 00:16:05.669 concrete, or adobe. And what does it do? Why 00:16:05.669 --> 00:16:08.090 is heavy good? It acts like a thermal battery. 00:16:08.490 --> 00:16:10.429 Let's look at the American Southwest, all that 00:16:10.429 --> 00:16:13.169 mission -style architecture. Thick adobe walls. 00:16:13.450 --> 00:16:16.429 Why? Because it's hot. It's hot during the day, 00:16:16.450 --> 00:16:18.830 but in the high desert, it can get close to freezing 00:16:18.830 --> 00:16:21.570 at night. The temperature swing is huge. Right. 00:16:21.690 --> 00:16:24.490 The thick walls absorb that brutal solar heat 00:16:24.490 --> 00:16:27.250 all day long. It takes hours for the heat to 00:16:27.250 --> 00:16:29.429 travel through the wall, so the inside stays 00:16:29.429 --> 00:16:31.529 cool while the sun is up. And then at night? 00:16:31.690 --> 00:16:34.110 At night, when the air outside drops to 30 degrees, 00:16:34.429 --> 00:16:37.190 that stored heat finally reaches the inside surface 00:16:37.190 --> 00:16:39.590 of the wall and radiates into the room, keeping 00:16:39.590 --> 00:16:41.909 you warm. It flattens out the temperature curve. 00:16:42.110 --> 00:16:44.570 So if you built that same house out of thin wood... 00:16:44.570 --> 00:16:47.710 You'd roast by day and freeze by night. The mass 00:16:47.710 --> 00:16:50.269 is the regulator. Fascinating. So that's passive, 00:16:50.529 --> 00:16:53.710 the building doing the work, but sometimes physics 00:16:53.710 --> 00:16:56.220 isn't enough. Sometimes you need a motor. You 00:16:56.220 --> 00:16:58.480 need a plug. You need active systems. Let's talk 00:16:58.480 --> 00:17:00.980 active systems. And obviously the poster child 00:17:00.980 --> 00:17:04.259 here is solar power, photovoltaics. Right. This 00:17:04.259 --> 00:17:06.380 is what everyone pictures when they think green 00:17:06.380 --> 00:17:08.900 building, the shiny blue panels on the roof. 00:17:09.059 --> 00:17:11.180 But I have to say, the research had a number 00:17:11.180 --> 00:17:13.660 that kind of bummed me out. It said commercial 00:17:13.660 --> 00:17:18.519 panels range from 4 % to 28 % efficiency. 28%. 00:17:18.519 --> 00:17:21.339 If I got a 28 on a math test, I'd be grounded. 00:17:21.359 --> 00:17:23.539 Is that... Good? It sounds terrible, doesn't 00:17:23.539 --> 00:17:25.740 it? That's awful. A standard gas turbine might 00:17:25.740 --> 00:17:29.079 be 40 % to 60 % efficient, but you have to change 00:17:29.079 --> 00:17:31.680 your perspective. With a gas turbine, you are 00:17:31.680 --> 00:17:34.339 paying for the fuel. You care deeply about wasting 00:17:34.339 --> 00:17:37.519 it. Okay. With solar, the fuel is free. It's 00:17:37.519 --> 00:17:39.799 falling from the sky in essentially infinite 00:17:39.799 --> 00:17:42.740 amounts. So wasting 72 % of infinite doesn't 00:17:42.740 --> 00:17:45.599 matter as much. Exactly. Even at 20 % efficiency, 00:17:45.940 --> 00:17:48.400 a standard roof can generate enough power to 00:17:48.400 --> 00:17:51.619 run the house. It's about viability, not perfection. 00:17:51.980 --> 00:17:55.500 I mean, in Germany, solar is standard and they 00:17:55.500 --> 00:17:57.799 have way less sun than most of the U .S. But 00:17:57.799 --> 00:17:59.440 you have to point them the right way. And this 00:17:59.440 --> 00:18:01.740 gets back to geometry again. The math of the 00:18:01.740 --> 00:18:04.880 angle. This is critical. You can't just slap 00:18:04.880 --> 00:18:06.920 them on flat. You need to look at your latitude. 00:18:07.220 --> 00:18:09.819 Why latitude? Because latitude tells you how 00:18:09.819 --> 00:18:12.039 far north or south you are from the equator. 00:18:12.220 --> 00:18:14.099 And the equator is where the sun is generally. 00:18:14.240 --> 00:18:16.200 You're trying to point your panels at the equator. 00:18:16.539 --> 00:18:19.619 Okay. So if I'm in New York, that's... Roughly 00:18:19.619 --> 00:18:22.140 40 degrees north latitude. Right. So to get the 00:18:22.140 --> 00:18:24.400 best annual average, you tilt your panels at 00:18:24.400 --> 00:18:27.700 40 degrees. That faces them directly at the average 00:18:27.700 --> 00:18:29.980 sun position over the year. But what if I really 00:18:29.980 --> 00:18:32.779 need power in the winter, when the days are short? 00:18:32.940 --> 00:18:35.500 In winter, the sun is low in the sky. So you 00:18:35.500 --> 00:18:37.779 need to tilt the panels up steeper to cache it. 00:18:37.859 --> 00:18:40.500 So more than 40 degrees. The rule of thumb is 00:18:40.500 --> 00:18:43.759 you take your latitude and add 15 degrees. So 00:18:43.759 --> 00:18:45.859 in New York, you'd tilt them to 55 degrees. And 00:18:45.859 --> 00:18:47.839 summer. The sun is high, so you flatten them 00:18:47.839 --> 00:18:51.259 out. Latitude minus 15 degrees. Got it. Now let's 00:18:51.259 --> 00:18:52.579 talk about the one that breaks my heart a little 00:18:52.579 --> 00:18:56.440 bit. Wind turbines. Ah, the rooftop wind turbine. 00:18:57.200 --> 00:19:00.039 The siren song of sustainable tech. I see ads 00:19:00.039 --> 00:19:02.720 for these. They look so cool. Like little corkscrews 00:19:02.720 --> 00:19:04.640 spinning on your roof. I always wanted one. But 00:19:04.640 --> 00:19:06.240 you're telling me they're basically lawn ornaments. 00:19:06.559 --> 00:19:09.579 I hate to be the bearer of bad news, but for 00:19:09.579 --> 00:19:13.019 most people, yes. Small wind is a trap. Why? 00:19:13.259 --> 00:19:15.720 It comes down to a specific law of physics called 00:19:15.720 --> 00:19:19.619 the cube law. And honestly, if you take one hard 00:19:19.619 --> 00:19:22.240 science concept away from this deep dive, make 00:19:22.240 --> 00:19:24.759 it this one. Okay, lay it on me. The cube law. 00:19:25.119 --> 00:19:27.440 The power available in the wind is determined 00:19:27.440 --> 00:19:30.259 by a formula, but the important part is one variable, 00:19:30.440 --> 00:19:34.740 velocity cubed. Cubed. So V times V times V. 00:19:34.900 --> 00:19:37.200 Exactly. That means the power isn't linear. If 00:19:37.200 --> 00:19:39.420 the wind blows twice as fast, you don't get twice 00:19:39.420 --> 00:19:42.700 the power. You get two times two. Eight times 00:19:42.700 --> 00:19:45.019 the power. Eight times the power. Okay. But the 00:19:45.019 --> 00:19:47.400 reverse must be true then. It is. Yeah. And that's 00:19:47.400 --> 00:19:49.099 the killer. If the wind speed drops by half. 00:19:49.299 --> 00:19:51.500 You lose, wait, you don't lose half the power. 00:19:51.539 --> 00:19:53.640 You lose seven eighths of your power. Exactly. 00:19:53.720 --> 00:19:57.599 You are left with 12 .5 % of the energy. A small 00:19:57.599 --> 00:20:00.599 drop in speed is a catastrophe for output. And 00:20:00.599 --> 00:20:03.599 where do we put rooftop turbines? On roofs where 00:20:03.599 --> 00:20:05.559 the wind is terrible. I thought roofs were windy. 00:20:05.799 --> 00:20:09.390 They're turbulent. Trees, other houses, chimneys, 00:20:09.509 --> 00:20:12.089 they all chop up the wind. They create friction. 00:20:12.230 --> 00:20:16.069 The wind speed at your roof line might be half 00:20:16.069 --> 00:20:18.930 of what it is 50 feet up in the clear. And because 00:20:18.930 --> 00:20:21.549 of the cube law, half the speed means practically 00:20:21.549 --> 00:20:25.019 zero electricity. You got it. So unless you live 00:20:25.019 --> 00:20:27.839 on a bald hill with 15 mile an hour consistent 00:20:27.839 --> 00:20:31.400 winds, don't buy a rooftop turbine. The maintenance 00:20:31.400 --> 00:20:34.180 costs alone will likely exceed the value of the 00:20:34.180 --> 00:20:36.400 electricity it generates. Consider my dreams 00:20:36.400 --> 00:20:38.480 crushed. Let's move to something that actually 00:20:38.480 --> 00:20:42.000 works. Solar water heating. This is the unsung 00:20:42.000 --> 00:20:44.119 hero. It's so much simpler than making electricity. 00:20:44.240 --> 00:20:46.480 You're just using the sun to get water hot. And 00:20:46.480 --> 00:20:49.039 the research mentioned evacuated tubes, which 00:20:49.039 --> 00:20:51.559 sounds like a medical procedure. It does, but 00:20:51.559 --> 00:20:54.369 it's brilliant engineering. Imagine a glass tube 00:20:54.369 --> 00:20:56.849 with a smaller dark -colored tube inside it. 00:20:56.970 --> 00:21:00.630 And in between the two, nothing. A vacuum. Like 00:21:00.630 --> 00:21:03.470 a thermos. Exactly like a thermos. A vacuum is 00:21:03.470 --> 00:21:05.609 a perfect insulator because there are no air 00:21:05.609 --> 00:21:08.890 molecules to transfer heat. So the sun hits the 00:21:08.890 --> 00:21:11.750 inner tube, heats the water to scalding temperatures, 00:21:12.049 --> 00:21:15.049 but the heat cannot escape back out. So even 00:21:15.049 --> 00:21:17.329 if it's freezing cold outside... The tube stays 00:21:17.329 --> 00:21:20.519 hot. These systems can be 80 % efficient. Compare 00:21:20.519 --> 00:21:23.799 that to the 20 % for solar electric panels. Thermodynamics 00:21:23.799 --> 00:21:26.539 loves heating water. Okay, let's move into the 00:21:26.539 --> 00:21:30.160 belly of the beast, the HVAC system. Because 00:21:30.160 --> 00:21:32.720 eventually, passive design isn't enough. We need 00:21:32.720 --> 00:21:35.160 to heat and cool the air. And the start of the 00:21:35.160 --> 00:21:37.839 show seems to be the heat pump. The heat pump 00:21:37.839 --> 00:21:40.500 is the most important appliance of the 21st century, 00:21:40.640 --> 00:21:43.839 period. That is a bold claim. Explain it to me 00:21:43.839 --> 00:21:45.859 like I'm five. Because heat pump sounds like 00:21:45.859 --> 00:21:48.480 it just makes heat, but it cools too. Think of 00:21:48.480 --> 00:21:50.759 it as a reversible refrigerator. Okay. Put your 00:21:50.759 --> 00:21:52.859 hand behind your fridge. It's warm, right? The 00:21:52.859 --> 00:21:55.619 fridge isn't making that heat. It is pumping 00:21:55.619 --> 00:21:58.059 the heat out of your food and dumping it into 00:21:58.059 --> 00:22:00.460 the kitchen. It's moving thermal energy from 00:22:00.460 --> 00:22:03.279 one place to another. Precisely. A heat pump 00:22:03.279 --> 00:22:06.500 does the exact same thing for your house. In 00:22:06.500 --> 00:22:08.400 the summer, it pumps heat out of your living 00:22:08.400 --> 00:22:10.619 room and dumps it outside. That's air conditioning. 00:22:10.880 --> 00:22:12.900 Okay, that makes sense. But flip a switch and 00:22:12.900 --> 00:22:15.759 it runs in reverse. It finds heat outside, pumps 00:22:15.759 --> 00:22:18.000 it in, and dumps it in your living room. But 00:22:18.000 --> 00:22:19.900 this is the part I struggle with. How does it 00:22:19.900 --> 00:22:22.740 find heat outside when it's 20 degrees in January? 00:22:23.160 --> 00:22:25.519 There's no heat there. It's freezing. Ah, that's 00:22:25.519 --> 00:22:28.059 where our human senses deceive us. 20 degrees 00:22:28.059 --> 00:22:30.940 Fahrenheit feels cold to us. But to a physicist, 00:22:31.259 --> 00:22:33.859 absolute zero, the point where there is literally 00:22:33.859 --> 00:22:37.019 no heat energy, is minus 460 degrees Fahrenheit. 00:22:37.319 --> 00:22:39.900 Okay. So at 20 degrees, there's actually a massive 00:22:39.900 --> 00:22:42.319 amount of heat energy in the air. It's just less 00:22:42.319 --> 00:22:44.940 hot than our skin. The heat pump can squeeze 00:22:44.940 --> 00:22:47.609 that heat out. concentrate it, and bring it inside. 00:22:47.910 --> 00:22:50.190 So it's extracting the hidden heat from the frozen 00:22:50.190 --> 00:22:53.869 air. Yes. And because it's moving heat rather 00:22:53.869 --> 00:22:56.950 than creating it by burning gas, it is magically 00:22:56.950 --> 00:22:59.910 efficient. A top -of -the -line gas furnace is 00:22:59.910 --> 00:23:03.049 maybe 95 % efficient. Which sounds pretty good. 00:23:03.250 --> 00:23:07.049 It is. But a heat pump can be 300 or 400 % efficient. 00:23:07.269 --> 00:23:09.490 That sounds like cheating. How is that possible? 00:23:09.950 --> 00:23:12.779 It feels like cheating. But it's just using the 00:23:12.779 --> 00:23:15.380 laws of thermodynamics. Yeah. For every one unit 00:23:15.380 --> 00:23:17.819 of electricity you put in to run the pump, you 00:23:17.819 --> 00:23:20.039 move three or four units of heat. And this isn't 00:23:20.039 --> 00:23:22.240 theoretical anymore. Scandinavia is going all 00:23:22.240 --> 00:23:24.440 in on this. Really? Because I always heard heat 00:23:24.440 --> 00:23:26.099 pumps don't work in the cold. That's the myth. 00:23:26.279 --> 00:23:28.680 Old ones didn't. Yeah. Modern ones work down 00:23:28.680 --> 00:23:32.359 to negative 15 degrees. In Norway, Finland, Sweden 00:23:32.359 --> 00:23:35.079 places with serious winters, there are now something 00:23:35.079 --> 00:23:38.079 like 25 heat pumps for every 100 people. If it 00:23:38.079 --> 00:23:40.720 works in Oslo, it works in Ohio. Fair point. 00:23:41.180 --> 00:23:43.039 Now, there's a variant of this that involves 00:23:43.039 --> 00:23:46.039 digging, geothermal. Ground source heat pumps. 00:23:46.160 --> 00:23:48.220 This is the Rolls -Royce version. Why dig? Why 00:23:48.220 --> 00:23:50.319 go to all that trouble? Because the air temperature 00:23:50.319 --> 00:23:53.859 changes wildly. It's 90 in summer, 10 in winter, 00:23:53.960 --> 00:23:56.900 but 6 feet underground. The temperature is constant. 00:23:57.000 --> 00:23:59.779 It's about 55 degrees year -round, anywhere on 00:23:59.779 --> 00:24:02.160 Earth. So it's a stable starting point. Exactly. 00:24:02.339 --> 00:24:05.180 In winter, you aren't trying to pull heat from 00:24:05.180 --> 00:24:07.640 10 -degree air. You're pulling it from 55 -degree 00:24:07.640 --> 00:24:10.420 dirt. It's much easier. And in summer. In summer, 00:24:10.579 --> 00:24:12.519 you aren't trying to dump heat into 90 degree 00:24:12.519 --> 00:24:14.880 air. You're dumping it in 55 degree dirt. It's 00:24:14.880 --> 00:24:18.119 way more efficient. But expensive. Very. You 00:24:18.119 --> 00:24:20.140 have to bring in drilling rigs. It can cost twice 00:24:20.140 --> 00:24:22.779 as much to install. But the running costs are 00:24:22.779 --> 00:24:25.200 tiny. Okay. Now we get to the part of the outline 00:24:25.200 --> 00:24:28.980 that I honestly thought was a typo. Passive daytime 00:24:28.980 --> 00:24:34.049 radiative cooling. PDRC. This section talks about 00:24:34.049 --> 00:24:36.750 harvesting the coldness of outer space. Are we 00:24:36.750 --> 00:24:39.109 building spaceships? What is happening here? 00:24:39.309 --> 00:24:41.789 It sounds like total sci -fi, doesn't it? But 00:24:41.789 --> 00:24:43.829 this is cutting -edge physics, and it's real. 00:24:44.029 --> 00:24:46.670 How does it work? Okay, so we know the sun heats 00:24:46.670 --> 00:24:49.309 the Earth with radiation, but the Earth also 00:24:49.309 --> 00:24:51.650 sends heat back out into space as radiation. 00:24:51.789 --> 00:24:56.190 The problem is the atmosphere clouds, CO2, water 00:24:56.190 --> 00:24:59.150 vapor, acts like a blanket. It traps a lot of 00:24:59.150 --> 00:25:00.910 that heat. That's the greenhouse effect. Got 00:25:00.910 --> 00:25:03.809 it. However... There is a loophole. There's a 00:25:03.809 --> 00:25:06.630 specific frequency of infrared light between 00:25:06.630 --> 00:25:10.369 8 and 13 micrometers wavelength that the atmosphere 00:25:10.369 --> 00:25:12.430 is transparent to. It's like a radio window. 00:25:12.670 --> 00:25:15.490 It's an atmospheric window. Heat at that specific 00:25:15.490 --> 00:25:17.869 frequency shoots right through the clouds, right 00:25:17.869 --> 00:25:19.789 through the air, and goes straight into the void 00:25:19.789 --> 00:25:22.829 of space. And space is cold. Space is incredibly 00:25:22.829 --> 00:25:25.880 cold, near absolute zero. So scientists have 00:25:25.880 --> 00:25:28.519 developed materials that are attuned to emit 00:25:28.519 --> 00:25:31.039 their heat at exactly that frequency. So they're 00:25:31.039 --> 00:25:32.940 basically broadcasting their heat directly to 00:25:32.940 --> 00:25:35.680 the universe. They are. And what happens to the 00:25:35.680 --> 00:25:38.940 material? It gets cold. Extremely cold. These 00:25:38.940 --> 00:25:41.980 panels can cool down to below the ambient air 00:25:41.980 --> 00:25:43.880 temperature. Wait, wait. It gets colder than 00:25:43.880 --> 00:25:45.880 the air around it? Even when the sun is shining 00:25:45.880 --> 00:25:48.000 directly at it. How is that possible? Because 00:25:48.000 --> 00:25:50.460 it's radiating heat away faster than it's absorbing 00:25:50.460 --> 00:25:53.559 it. It creates a cooling effect without using 00:25:53.559 --> 00:25:56.140 any electricity. If you cover a roof with this 00:25:56.140 --> 00:25:59.500 stuff, you can reduce AC needs by 30 to 40 percent. 00:25:59.720 --> 00:26:02.019 You are essentially connecting your building 00:26:02.019 --> 00:26:05.599 to the ultimate heat sink, the universe. Harvesting 00:26:05.599 --> 00:26:08.599 the void. That is poetic. Okay, let's come back 00:26:08.599 --> 00:26:11.339 down to Earth, literally. Let's talk about materials. 00:26:11.460 --> 00:26:14.059 We've talked about energy, but what are we building 00:26:14.059 --> 00:26:17.029 these houses out of? We're seeing a return to 00:26:17.029 --> 00:26:19.210 what the research calls the natural palette. 00:26:19.369 --> 00:26:22.890 So timber, straw, stone. The three little pigs 00:26:22.890 --> 00:26:25.670 strategy. In a way. But we have to look at carbon 00:26:25.670 --> 00:26:28.349 again. Trees absorb carbon dioxide as they grow. 00:26:28.490 --> 00:26:30.289 When you chop a tree down and turn it into a 00:26:30.289 --> 00:26:32.809 beam, that carbon is locked inside the wood. 00:26:32.869 --> 00:26:36.509 It's sequestered. Whereas making steel or concrete 00:26:36.509 --> 00:26:39.650 creates carbon emissions. Exactly. So a wood 00:26:39.650 --> 00:26:42.130 building is a carbon bank. A steel building is 00:26:42.130 --> 00:26:44.920 a carbon source. And then there's bamboo. I feel 00:26:44.920 --> 00:26:47.140 like bamboo is the kale of construction. Everyone 00:26:47.140 --> 00:26:49.720 is suddenly obsessed with it. That's a fair comparison, 00:26:50.019 --> 00:26:53.799 but the obsession is warranted. Bamboo is a grass, 00:26:53.859 --> 00:26:57.079 not a tree. It grows incredibly fast. You can 00:26:57.079 --> 00:26:58.900 harvest it for construction in three to five 00:26:58.900 --> 00:27:02.420 years. An oak tree takes 40 to 60 years. So it's 00:27:02.420 --> 00:27:05.119 renewable on a human timescale, not a generational 00:27:05.119 --> 00:27:08.140 one. Exactly. And it's incredibly strong. Pound 00:27:08.140 --> 00:27:10.359 for pound, it has a tensile strength that rivals 00:27:10.359 --> 00:27:13.049 steel. And what about insulation? We're not just 00:27:13.049 --> 00:27:15.390 using that pink fiberglass cotton candy anymore. 00:27:15.589 --> 00:27:18.309 No, thankfully. We're seeing sheep wool. We're 00:27:18.309 --> 00:27:21.390 seeing recycled denim. Literally ground up old 00:27:21.390 --> 00:27:23.950 blue jeans. I like the idea of my house wearing 00:27:23.950 --> 00:27:27.210 Levi's. And then there's the weirdest one. Mycelium. 00:27:27.789 --> 00:27:30.029 Mushrooms. Mushroom roots. You can take agricultural 00:27:30.029 --> 00:27:32.609 waste corn stalks, husks, put them in a mold, 00:27:32.710 --> 00:27:35.210 and introduce mushroom spores. And what happens? 00:27:35.490 --> 00:27:37.950 The mycelium eats the waste and grows into a 00:27:37.950 --> 00:27:40.410 dense, foam -like network that fills the mold. 00:27:40.569 --> 00:27:43.970 You bake it to stop the growth, and boom, you 00:27:43.970 --> 00:27:46.490 have a fire -resistant insulating panel that 00:27:46.490 --> 00:27:49.710 is 100 % compostable. That is wild. You're literally 00:27:49.710 --> 00:27:52.519 growing your insulation. But I have to play devil's 00:27:52.519 --> 00:27:54.539 advocate here. Just because something is natural 00:27:54.539 --> 00:27:56.579 or recycled, does that automatically mean it's 00:27:56.579 --> 00:27:59.720 good for you? The research had a section on VOCs. 00:28:00.359 --> 00:28:04.000 Volatile Organic Compounds. And this is the gotcha 00:28:04.000 --> 00:28:06.299 of green building, isn't it? Green does not always 00:28:06.299 --> 00:28:09.720 mean healthy. It's a huge paradox. VOCs are the 00:28:09.720 --> 00:28:14.099 chemicals that off -gas from paints, glues, carpets, 00:28:14.099 --> 00:28:16.380 furniture. They cause sick building syndrome, 00:28:16.579 --> 00:28:19.119 headaches, asthma, that kind of thing. Right. 00:28:19.200 --> 00:28:21.829 And here's the kicker. A California study showed 00:28:21.829 --> 00:28:24.190 that some materials labeled recycled or green 00:28:24.190 --> 00:28:27.569 actually had higher toxic emissions than traditional 00:28:27.569 --> 00:28:30.509 material. Because recycled just means it was 00:28:30.509 --> 00:28:33.309 used before. It doesn't mean it's safe. And natural 00:28:33.309 --> 00:28:36.130 is tricky, too. Arsenic is natural. Formaldehyde 00:28:36.130 --> 00:28:38.390 is natural. You can't just trust the vibe or 00:28:38.390 --> 00:28:40.650 the label. You have to check the specific emission 00:28:40.650 --> 00:28:43.789 standards. So don't just sniff the cork flooring 00:28:43.789 --> 00:28:46.279 and assume you're safe. Now, we have these ancient 00:28:46.279 --> 00:28:49.059 materials like straw and stone, but the research 00:28:49.059 --> 00:28:51.480 also pointed to a very, very futuristic direction. 00:28:51.859 --> 00:28:54.279 Lab -grown materials. This is straight out of 00:28:54.279 --> 00:28:57.400 MIT. In 2022, researchers were working on growing 00:28:57.400 --> 00:29:00.440 Zinnia elegans cells in a lab. Growing plant 00:29:00.440 --> 00:29:03.480 cells? Without the plant? Like in a petri dish? 00:29:03.779 --> 00:29:06.720 Yes. Think of it like lab -grown meat, but for 00:29:06.720 --> 00:29:09.279 wood. They take the cells and grow them in a 00:29:09.279 --> 00:29:11.599 gel matrix. And they can tune the properties. 00:29:11.880 --> 00:29:13.740 Tune them? What does that mean? They can add 00:29:13.740 --> 00:29:15.900 hormones to tell the cells to grow denser or 00:29:15.900 --> 00:29:18.319 stiffer. They can grow a specific shape like 00:29:18.319 --> 00:29:21.000 a chair leg or a beam. So there is zero waste, 00:29:21.180 --> 00:29:24.299 no sawdust, no bark. So you could theoretically 00:29:24.299 --> 00:29:27.299 grow a wooden wall stud that is perfectly straight 00:29:27.299 --> 00:29:30.339 and never warps. That's the dream. No deforestation. 00:29:30.619 --> 00:29:33.839 No waste. But it raises really complex questions. 00:29:34.319 --> 00:29:37.660 Like what? Well, if we stop harvesting forests... 00:29:37.759 --> 00:29:40.019 What happens to the rural economies that depend 00:29:40.019 --> 00:29:42.920 on timber? And strangely, what happens to wildfire 00:29:42.920 --> 00:29:45.440 management? Managed logging often helps clear 00:29:45.440 --> 00:29:47.819 underbrush. If we stop tucking forests, they 00:29:47.819 --> 00:29:50.539 just burn. It really is a complex web. You solve 00:29:50.539 --> 00:29:52.619 one problem and you create three others. That 00:29:52.619 --> 00:29:55.000 is the history of technology. So before we wrap 00:29:55.000 --> 00:29:57.279 up, we have to talk about context. Because you 00:29:57.279 --> 00:29:59.599 could build the perfect house lab -grown wood, 00:29:59.700 --> 00:30:02.670 cooled by space, heated by the earth. But if 00:30:02.670 --> 00:30:04.990 you put it in the wrong place, none of it matters. 00:30:05.130 --> 00:30:06.809 This is what the research calls the greenhouse 00:30:06.809 --> 00:30:09.609 in the middle of nowhere fallacy. Explain that. 00:30:09.690 --> 00:30:12.750 Imagine a LEED Platinum Eco Home. It's perfect. 00:30:12.970 --> 00:30:15.950 Net zero. It makes its own power. It recycles 00:30:15.950 --> 00:30:19.029 its own water. But it's located on a five acre 00:30:19.029 --> 00:30:21.930 lot, 30 miles from the nearest town. So you have 00:30:21.930 --> 00:30:25.009 to drive everywhere. Exactly. You are driving 00:30:25.009 --> 00:30:28.880 your SUV 30 miles to get a gallon of milk. The 00:30:28.880 --> 00:30:30.980 carbon emissions from your transportation will 00:30:30.980 --> 00:30:33.539 completely wipe out the carbon savings of your 00:30:33.539 --> 00:30:35.980 efficient house. So a drafty little apartment 00:30:35.980 --> 00:30:39.079 in a dense city might actually be greener? Almost 00:30:39.079 --> 00:30:41.539 certainly. If you live in a walkable neighborhood, 00:30:41.799 --> 00:30:44.400 take the subway and share walls with your neighbors, 00:30:44.579 --> 00:30:47.579 which insulates you for free, your carbon footprint 00:30:47.579 --> 00:30:50.740 is tiny compared to the eco -warrior in the excerpts. 00:30:50.900 --> 00:30:54.400 This is the core idea of new urbanism. Yes. Density 00:30:54.400 --> 00:30:57.539 is green. Walkability is green. Sustainable architecture 00:30:57.539 --> 00:30:59.539 isn't just about the building. It's about where 00:30:59.539 --> 00:31:01.660 the building sits in the web of the city. And 00:31:01.660 --> 00:31:04.660 how does water fit into that urban picture? Cities 00:31:04.660 --> 00:31:07.220 have a huge problem with water. Concrete doesn't 00:31:07.220 --> 00:31:09.960 absorb rain. So we get flash floods. Right. We 00:31:09.960 --> 00:31:11.700 need green roofs. Putting grass on the roof. 00:31:11.859 --> 00:31:15.960 Or sedum. Or gardens. Or even small trees. The 00:31:15.960 --> 00:31:18.759 roof acts like a sponge, absorbing stormwater 00:31:18.759 --> 00:31:21.869 and releasing it slowly. It also insulates the 00:31:21.869 --> 00:31:23.930 building, and it fights the urban heat island 00:31:23.930 --> 00:31:26.190 effect. That's where the city is hotter than 00:31:26.190 --> 00:31:28.109 the surrounding countryside. Right. All that 00:31:28.109 --> 00:31:31.390 black asphalt and dark roofing soaks up the sun. 00:31:31.630 --> 00:31:34.670 Green roofs cool the entire city down. It seems 00:31:34.670 --> 00:31:36.710 like there's a digital layer to all of this, 00:31:36.710 --> 00:31:38.930 too. The research mentions something called BIM. 00:31:39.549 --> 00:31:42.049 Building Information Modeling. This is the brain 00:31:42.049 --> 00:31:44.750 of sustainable design. Is this like SimCity for 00:31:44.750 --> 00:31:48.279 architects? Actually, yes. That's a perfect analogy. 00:31:48.539 --> 00:31:51.000 It allows architects to build a digital twin 00:31:51.000 --> 00:31:53.420 of the building before they pour a single drop 00:31:53.420 --> 00:31:55.940 of concrete. A digital twin? They can simulate 00:31:55.940 --> 00:31:58.200 everything. What happens if we rotate the building 00:31:58.200 --> 00:32:00.220 five degrees? What happens if we use triple pane 00:32:00.220 --> 00:32:02.339 windows instead of double? What's the embodied 00:32:02.339 --> 00:32:04.880 carbon of this steel beam versus that wood one? 00:32:05.039 --> 00:32:07.059 And the computer just spits out the carbon numbers. 00:32:07.619 --> 00:32:10.650 Instantly. It takes all the guesswork out. You 00:32:10.650 --> 00:32:12.490 aren't just hoping it's sustainable. You know 00:32:12.490 --> 00:32:14.410 it is because you've already simulated the next 00:32:14.410 --> 00:32:18.309 50 years of weather and energy use. That is incredible. 00:32:18.470 --> 00:32:21.309 We have covered a massive amount of ground today. 00:32:21.490 --> 00:32:23.789 We really have, from top to bottom. We've looked 00:32:23.789 --> 00:32:26.190 at the hidden carbon costs, that deadly cement. 00:32:26.430 --> 00:32:29.210 We've looked at the geometry of the sun, the 00:32:29.210 --> 00:32:31.630 coffee cup, and the salt box. The physics of 00:32:31.630 --> 00:32:34.329 wind. We've learned about the cube law of wind 00:32:34.329 --> 00:32:36.549 and why I shouldn't put a turbine on my roof. 00:32:36.769 --> 00:32:39.269 We've talked about harvesting the cold of space 00:32:39.269 --> 00:32:42.170 and growing wood in a petri dish. It's a lot. 00:32:42.549 --> 00:32:44.930 But it shows that the solution isn't just one 00:32:44.930 --> 00:32:46.930 thing. It's not just technology and it's not 00:32:46.930 --> 00:32:49.089 just going back to nature. It's a synthesis. 00:32:49.369 --> 00:32:51.950 If you had to leave the listener with one thought 00:32:51.950 --> 00:32:55.130 to chew on, one synthesis of all this, what would 00:32:55.130 --> 00:32:58.519 it be? I keep thinking about that contrast. The 00:32:58.519 --> 00:33:01.740 ultra future of lab -grown plant cells versus 00:33:01.740 --> 00:33:04.720 the ultra past of mud, straw, and stone. Right. 00:33:04.839 --> 00:33:06.900 And I think the most sustainable future isn't 00:33:06.900 --> 00:33:09.079 about choosing one or the other. It's about the 00:33:09.079 --> 00:33:11.539 marriage of those two. High -tech analysis of 00:33:11.539 --> 00:33:15.599 ancient wisdom. Exactly. We use BIM, the high 00:33:15.599 --> 00:33:18.500 -tech, to perfectly optimize the placement of 00:33:18.500 --> 00:33:21.880 a window, the ancient wisdom. We use advanced 00:33:21.880 --> 00:33:24.259 heat pumps to heat a building made of straw. 00:33:24.750 --> 00:33:27.190 we don't need to reinvent the wheel we just need 00:33:27.190 --> 00:33:29.750 to use our new tools to make the old wheels spin 00:33:29.750 --> 00:33:31.869 better and more intelligently that's a great 00:33:31.869 --> 00:33:34.170 perspective and for you listening here's a little 00:33:34.170 --> 00:33:36.269 homework look at the building you're in right 00:33:36.269 --> 00:33:38.789 now which way do the windows face is that green 00:33:38.789 --> 00:33:41.930 flooring actually healthy start seeing the invisible 00:33:41.930 --> 00:33:44.650 flows of energy and materials around you once 00:33:44.650 --> 00:33:46.970 you start looking you can't stop seeing it you'll 00:33:46.970 --> 00:33:49.069 be looking at the surface area of every coffee 00:33:49.069 --> 00:33:52.890 shop you walk into I know I will. Thanks for 00:33:52.890 --> 00:33:54.730 diving dip with us today. A pleasure as always. 00:33:54.849 --> 00:33:55.470 See you next time.