Beyond Zero interviews Dan Chiras, author of numerous books including "The Solar House: Passive Heating and Cooling", about sustainable building

Beyond Zero speaks to Dan Chiras, author of over 20 publications including "The Solar House", about sustainable building, the construction industry and designing around the sun to reduce emissions.

Beyond Zero speaks to Dan Chiras

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Matthew Wright:      Today we are very fortunate to be speaking to Dan Chiras who is an author and a green building consultant. I’ve been lucky enough to have a few of his books on my shelf for many years and have read them. In fact, I had a bit of a revisit, very exciting. The first one I got was called The Solar House – Passive Heating and Cooling and another book I got was called The Natural House. And if you read the intro to it, it talks about a lot of well-meaning people in the seventies, how they built solar houses and that some of them didn’t quite cut it. And how you could actually inform the public more on how you could have an autonomous house, how you could have a house with a very low annual fuel bill. So he can tell us a bit about himself, I’ll grab him on the line now. Hello, are you there Dan

Dan Chiras:      I’m doing quite well, and yourself?

Matthew Wright:      Yes, great. And I’ve also got Jenny assisting me in the studio.

Jenny:    Hello Dan

Dan Chras: Hi Jenny

Matthew Wright:      It’s pretty exciting. I guess ten years ago when I bought your book I didn’t think that I would be talking to you on the radio in the future. So here I am and, having read your book, it’s pretty exciting. Could you tell us a bit about yourself and how you got inspired and interested in green building? Was it an interest in just energy security or was it an environmental interest? How did you start?

Dan Chiras:      I came from the environmental perspective. I was deeply interested in the environment back in the 1970s. Actually, while I was doing a PhD in reproductive physiology I started reading on the side about the environment and by the time I finished my PhD I knew that I really needed to go in a whole different direction. So I was very fortunate in my very first teaching job: my department chairman said, “Dan, you know you have to teach these biology courses and then you can do whatever else you want”. So I took that as a licence to educate myself all about the environment. And that’s what I basically spent the last 35 years working on.

It first became an interest in environmental issues and it occurred to me that while we have so many environmental issues, we were treating them all as if they were somehow separate from each other. Isolated diseases if you will. And it occurred to me that there were fundamental problems in our society, like the kinds of energy that we rely on and the way we use resources, and those sorts of things were at the root of our environmental crisis. And from there I became very interested in green energy and green building, and I spent the last ten, fifteen years working exclusively in those areas.

Matthew Wright:      I understand you’ve lived in a number of passive solar houses and before we talk about those, can you tell listeners what a passive solar house is and what’s possible.

Dan Chiras:      Well, I consider a passive solar house as a house with a heating system that has only one moving part and that’s the sun. And what it relies on is the low angle winter sun shining in. In our case in the northern hemisphere it's the south facing windows and in your case in the southern hemisphere it’s that low angle winter sun that shines in through the north facing windows. And just when we need the heat it’s there, it’s available to us, if you design the house correctly.

Typically what we do is we design the house so it’s oriented, in your case, to the north, the long axis is oriented east and west, and you concentrate the windows along that north side. And then the house really becomes a very large solar collector. Sunlight streams in through those north facing windows, warms up the house and provides plenty of heat throughout much of the winter season if you’re in a climate that’s cold but sunny.

So it’s really a heating system that has no moving parts except the sun, and that’s why we call it a passive solar system. It’s passive solar heating and very little maintenance, obviously, or no maintenance at all, and no moving parts, no noisy fans or pumps. And no electricity required to drive pumps and fans, and it’s one of the best solar deals out there, in fact it is the best solar deal out there. You know, you can build a passive solar house without spending any more money. Maybe you might end up spending a few percent more but typically you can build a passive solar house at the same cost as a traditional home. And if you do it right you get free heat for life.

Matthew Wright:      Certainly in Australia, builders en masse haven’t really taken the principles of passive solar design and run with them. I mean, there’s been some state regulations where we have a ten star system and they’re sort of half way there at five stars and five stars still involves considerable heating and cooling energy input on an annual basis. Why do you think builders are resistant to being the first movers and generally need to be dragged by regulation?

Dan Chiras:      You know that’s a real good question and I don’t know if it’s a resistance, or – and I don’t mean this in a pejorative sense – or just ignorance to what’s available to us. Construction is a very conservative trade. People build how they think they’ve always built and so what I find here in the States is that builders are just building houses – we’ve always had cheap energy so they didn’t have to think much about insulation and weather sealing and air sealing a home. And they didn’t have to think much about passive solar because energy was cheap.

So I think that a lot of it has to do with just a long tradition of building homes, if you will, the wrong way. And if we just keep doing that with cheap energy, and before there were any concerns for global climate change, you know, nobody really cared about how much fossil fuel we burned up. So I think that’s part of it, and there is a reluctance I’ve found among builders here in the States, and very likely as well in Australia, to change. To try something different. It’s really a shame because as I said earlier, you can build a home, a passive solar home, at very little extra cost, if any. And you basically can create a house that gets somewhere between fifty and maybe eighty or ninety percent of its heat for free. And free heat for life.

People always ask me, “Why build solar?” My response is, “Why wouldn’t you?” Why wouldn’t you build a home that’s going to heat itself naturally? And here’s the other part of that whole equation: everything that you do to passively heat a home – add the insulation, the proper orientation of the home, overhang, air sealing – all of those things that you do to make the home perform better in winter also keep it cooler in the summer. So not only do you get free heat for life but you get free cooling as well. And you know, to me it’s just a matter of ignorance, people not realising what the benefits are and clearly even if they do hear about the benefits they don’t want to venture out of that nice comfortable realm of what they’re already building.

Matthew Wright:      If someone’s just discovering passive solar houses, the first thing that they may not understand is the elevation of the sun, and generally it depends on the latitude of where you are in relation to between the equator and the poles. But obviously if you’re getting down south in Australia or right up north in the US it’s pretty apparent that the sun in winter is very low on the horizon and in summer it’s high up in the sky.

The first challenge, I guess, for people just discovering this is that they think, “Oh this house is going to become incredibly hot if we have all this glazing”, because they don’t understand that in summer the sun won’t be shining in through those vertical north facing windows.

Dan Chiras:      You’re absolutely right. In fact, I have to chuckle when you say this because my children’s bus driver used to always remark to my boys, “Well you guys must bake in that house in the summer with windows on the south side”. Clearly he was ignorant of the fact that the sun is high in the sky, and there’s a 47 degree difference between that lowest angle of the sun in the winter and the highest angle in the summer.

The way we design solar homes is that we design them with some overhang and/or eaves that protects those south facing windows as well during the summer so you’re protected from that high angle summer sun. That’s something I didn’t learn in school, did you? You don’t learn about the fact that the sun is lower in the sky in the winter and higher in the summer. That ought to be required in the education for every youngster in school so they get the idea behind passive solar. And really, that’s the principle. That’s the secret of passive solar – that the sun is at a different angle. The altitude angle varies between the summer and the winter. It’s low in the winter sky, which allows the sun to come in when we need it the most, and it’s high in the summer sky, beating down on our roofs and not entering the windows of our home and so the house stays nice and cool.

Matthew Wright:      Now just to remind listeners, we’re speaking to Dan Chiras and he’s a PhD in physiology and author of The Solar House. In fact, author of 21 books. Another one’s called The Natural House. Fantastic publications available and also regular contributor to many news magazines and blogs including mother earth news and so on.

Now Dan, the next challenge I think for a builder or someone planning on a passive solar house, is the ratio of glazing to floor area to thermal mass. Now I think that’s the one that involves a bit of technical nous. Could you comment on how that challenge is addressed in people who maybe aren’t physicists with thermodynamics degrees?

Dan Chiras:      Well, absolutely. It reminds me of so many people that come to me and say, “Well, I was at a passive solar home and it just didn’t work” or “I owned one and it got so hot”. “And there was too much glass”, they would say. “In our case it was too much glass on the south facing wall”.  Typically the reason for that is that they didn’t have enough what we call ‘thermal mass’ – concrete floors or brick floors or tiled floors, some kind of masonry-type material that absorbs that heat during the day. That’s one of the most critical things, that if you orient your home properly, if you concentrate the windows on the north side and allow that sunlight to come in, you’ll also need a sponge to sponge up that heat and hold that heat during the day. If you don’t, it gets much too hot. The house gets way too hot and then the temperature drops significantly at night.

A lot of times we build passive solar homes on a slab, it’s just a four inch thick concrete slab, insulated underneath, and that slab acts as thermal mass. It absorbs that heat during the day and it does two things. One is that it keeps the house from getting too hot during the day, so the temperature rises up into the 70s – that’s Fahrenheit not Celsius – and then at night that thermal mass gives off heat and that heat radiates into the room. It allows the temperature to stay higher during the evening so the temperature might swing from 75 degrees Fahrenheit during the day and drop down to 65 at night.

Without the thermal mass, what you’ll see is the temperature can get as high as 85, even as high as 90 degrees during the day, which is of course an unbearable temperature. Much too hot. And it will drop into the 50s at night which is unbearably cold. So that’s the benefit of thermal mass. I like to think of it as a thermal sponge, a heat sponge. Something that will absorb that heat during the day and then release it at night or release it on cloudy days when the sun’s not shining. It’ll release it when you need the heat.

And it’s really important that you get the ratios right. If you have a certain amount of glass on the south side, you have to have the appropriate amount of thermal mass, and I don’t really want to get into the details of how you do that. But, it’s really important, and I outline all those in my book The Solar House. I outline those ratios and I’m actually happy if any readers want to email me, I’m happy to answer those questions, I can give them more detail in private. You can email me at danchiras@evergreeninstitute.org. I’m happy to give you what we call the ‘glass to mass ratios’. You have a certain amount of glass; how much thermal mass should you have inside the home to prevent overheating.

Matthew Wright:      Is there any move towards creating open source reference designs and publish them on a website or something along those lines for different climate zones? Is there anyone trying to spearhead an initiative like that to help people out?

Dan Chiras:      I haven’t seen that. There are some designs online, and they’re not very expensive at all, but I just haven’t seen any open source designs. It’d be a lovely contribution to humanity for someone to do that, to sketch some designs. But the thing to remember, when you design a house, is that you design around the sun. If you’re designing more specifically a passive solar home, you design the house around the sun.

Most of our houses we design around the 'use patterns': you know, we want the kitchen here next to the garage so when you walk in with the groceries you can deposit them on the kitchen table and put them in the refrigerator. So we design the home for utility, which is very important. But with a passive solar home you design around the sun. How they design automobiles in Detroit, Michigan, is they design around the passenger.

When you design a passive solar home you have to think first: where's the sun going to come in, where do I want the most sun? Typically you’ll want sunlight mostly in living rooms, maybe if you have a daytime office in your home, you would want the sun to be in there to heat that room. And other rooms that require less heat, like a bedroom or a pantry or a laundry room, in the southern hemisphere you’d put those on the south side of the home, away from the sun. It may sound complicated but it’s really quite easy to do and you just think about what rooms you want to have the most heat, and those rooms would be on the north side of the building in a passive solar home in the southern hemisphere.

Matthew Wright:      Are there many people in the US living in actual autonomous houses so that on annual basis there’s no external heating input?

Dan Chiras:      It’s actually really quite difficult to do that. I've lived in an off-grid home in Evergreen, Colorado, at 8000 feet above sea level, for fourteen years. It’s an earth sheltered home, it’s built into the hill side, it’s super insulated, massive levels of insulation, it's passive solar, and we’ve been pretty much able to heat that home for fourteen years with solar energy – passive solar – and a little bit of firewood. We burn a cord of wood a year, and a cord is a four foot by four foot by eight foot pile of wood. So that’s a pretty small amount of wood in a house which is a twenty four hundred square foot home; a lot of people would burn eight or ten cords of wood to make it though that winter.

There’s a lot of people in the United States, and indeed throughout the world, that are working very diligently to create homes that actually produce as much energy as they consume. We call that a net zero energy home.

My educational centre, the Evergreen Institute, has relocated to east central Missouri and we had a tragedy last Sunday. Our home – where we also house other faculty who come to teach, and house students occasionally, and there’s also a kitchen and shower in there for students – unfortunately that burned to the ground on Sunday. We had an electrical fire and the facility burned to the ground. While it's a tragedy, and I’m really quite bummed out by the prospect of having to rebuild, we’re going to make an attempt to build that home to be net zero energy so it basically produces as much energy as it consumes. We’ll do that with a solar system and a wind system and super insulation. We will build very thick walls, we will probably have R-50 or R-60 insulation in the walls and R-100 in the ceilings which is way more than our building codes call for. [Divide these R-values by 5.7 to get the equivalent Australian R-value in SI units.] But it’s the kind of effort that you need to take to create a truly sustainable home that will basically not require a lot of outside energy. We'll be able to heat that home with energy from the sun, and maybe a little bit of electricity which we generate from our solar and wind systems.

Matthew Wright:      That’s obviously very unfortunate but on the other hand possibly an opportunity to also document the build stage, given that there will be a lot of focus on your organisation?

Dan Chiras:      Absolutely. We will probably post that on the blog. We’re still haggling with the insurance companies right now but can probably begin work on it this summer and we’ll keep people posted. And hopefully folks can learn from this. I’m hoping builders will learn from this and realise that with a little bit of extra money you can create a home that’s basically autonomous. Either no energy bill or a very low energy bill. And be quite comfortable too, you don't have to freeze in the dark. You can build an extremely comfortable home as well.

Matthew Wright:      Yes, why would you pay energy bills or bring energy into a site that doesn’t need it when the sun is delivering it most days? Jenny has a question, not around necessarily the site disaster you had there with your institute’s house, but more around those old examples of where solar houses weren’t built properly and what the social effect of that is.

Jenny:      Because you mentioned the things that go wrong, I think that can be exponentially damaging for the whole area of solar and sustainability housing because it’s that ripple effect where a person hears a bad story and so people get doubtful. And there’s a bit of a scare campaign running from, maybe, people whose interests lie in another direction that may not be sustainable. Has that been problematic in America at all?

Dan Chiras:      Absolutely. It seems like there are wolves out there. The minute something green goes wrong, they jump all over it and they make big news of it to try to discredit what we're doing. Here’s a real good example: some friends of mine live in Moab, Utah, and there was a straw home being built and at the same time there was a condominium being built out of wood. It turns out that both buildings caught fire during construction and burned to the ground the same day. Straw-built is typically very fire-safe. This house was under construction so there was a lot of loose straw on the ground, it caught fire and both buildings burned to the ground.  Of course the front page of the Moab newspaper said “Straw bale burned”.

So it’s a real problem we face here in the States, and perhaps elsewhere, that there are folks out there who want to discredit what we're doing. They want to find any anecdotal evidence, anything possible to make it look like what we’re doing isn’t right. And the sad thing about it is that people catch on to that, folks hear that and go, “Gee, I don’t want to do passive solar it doesn’t work”.

Jenny:      They’re just looking at a paper with a fire on the front page so it's understandable.

Dan Chiras:      Precisely. Here’s another example: some people will install wind turbines and put them on too short towers, and the wind turbine doesn’t perform very well when it’s down towards the ground. It does much better on a taller tower. And so that person will say, “Gee, I tried wind and it just doesn’t work”, and that gets spread around and everybody who knows that person tells the story to other people and next thing you know you’ve got hundreds of people thinking, “Gee, wind energy doesn’t make sense”. So it’s a real problem that we have to combat all the time and it also makes us, I think, be very responsible and very careful in how we do things, to make sure that we don’t slip up, that we don’t make a mistake.

Jenny:      Certainly. And so in order to spread out some more information so people can also learn about it themselves and also access the builders who will be using these practices, are you involved with, or do you know of, sustainability advocacy groups around the US?

Dan Chiras:      Well, there are. Our group is a training centre, that’s how we try to get the word out there. We try to train and we focus our attention on architects, builders, carpenters, electricians, plumbers – folks who are out there in the field who have an interest in this. But a lot of them come to our workshops quite dubious about the whole thing. They’re sort of interested but they’re kind of dubious whether this stuff really works. And when they go away, they go away with a good solid understanding that this stuff does work if done right.

There are other groups, I don’t know if there are really any advocacy groups that really just promote this stuff, but there are a lot of educational centres that are in our own way trying to promote it. One group is the Midwest Renewable Energy Association and they’re based in Wisconsin. Every year they have a big energy fair: they bring in folks from all over the country, certainly all over the Midwest, and ten thousand to twelve thousand people, and they have a lot of displays and lectures. I think that if you could consider any action advocacy, that would be one group that does it. And they do it by trying to teach people – let people touch these sorts of technologies if you will, to actually get some first hand experience with them so that they realise this is truly legitimate, that this stuff works. And again – if done right.

Matthew Wright:      Now, from my perspective it seems that with regulation slowly creeping in the direction of passive solar houses, that things are a lot more positive these days than they have been say ten, twenty years ago. And then there’s the added benefit that solar photovoltaic – those rooftop solar cells that are now getting installed everywhere, in fact a massive 18,000MW in Germany now – have come down in price so much. So do you think there is quite a positive signal coming in and the future is looking good?

Dan Chiras:      Absolutely. I think the world’s going solar and wind. To be really honest with you, both solar electricity and wind energy are the fastest growing sources of energy in the world, bar none. And I think that the world has got it. I think the world realises that we really need to make the transition and there are countries that are leading the charge. The United States, not so much through its government until recently, but the United States, Germany, Japan, Spain, Denmark, a number of countries are really leading the charge and I truly think that the world is going to green energy and those of us who will live another twenty years will see a major shift in the way energy is generated.

Matthew Wright:      Fantastic. Look, we’re going to have to go now and I think that it really is exciting and I’ve felt myself in the last two to three years that things have really moved so fast and the fossil fuels are falling by the wayside. Great to speak to you and we hope to get you again on the program soon.

Dan Chiras:      Absolutely, I’d love to and it’s been a real pleasure chatting with you guys.

Matthew Wright:      Thanks very much. We’ve been speaking to Dan Chiras and he is the author of The Natural House and The Solar House so you can check out

Dan Chiras online. Thank you for joining us.

Transcript by Amy