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The 4 Donkey Method of BioClimatic Design

... or how to build a passive solar home, and do it really green!
by Ron Swenson

Here it is: The secret to bioclimatic design.

The four donkeys are Glass Grass Gas and Mass.

Some call it Passive Solar. That's 5 donkeys, just one too many for me. I get too confused. (I use my thumb for other things besides counting. Hitch-hiking, for example.)

Pay attention to these 4 donkeys and you can't go wrong. With them you can create a building that will survive without the heroic effort of our ancient and feeble fossil fuels. They are getting reeeeealllly old and tired, so you just feed these donkeys on carbohydrates (not hydrocarbons) and you will be able to perform wonders.

Even the ancients figured it out -- in Mesa Verde, an early passive solar community.


Everyone knows how comfortable it can be to sit in the sun behind a window on a cold winter day. So all you gotta do is put in enough of them (not too many either) and put 'em in the right place.

Well, I know if you live in Saudi Arabia or someplace, it can be hell to sit in front of that window. So you gotta have a shade. But where do you put the shade? On the outside, folks.

Think about it. Drapes are wonderful to keep the neighbors from watching you. But they don't do much for you, either to keep the heat in at night when you need it or to keep the heat out in the day when you're trying to get rid of it. Just because you can't find an outdoor shade on the market is no excuse. Build one. You can figure it out. Maybe you can use some grass. Like put up some grass mats.

Ah, but I'm getting ahead of myself. We have other important things to do with Grass, but first...

Getting down to specifics (it's sooooo simple),
  • Windows South
  • Cowpath: Sometimes highways get built following old cowpaths, even though cars may not have quite the same requirements as cows. Same is true for buildings. If buildings are oriented to streets, things will often get out of hand.
  • Oh, and if you happen to be in a big building and can't get light from the south, you can check out some clerestory window and skylight options.
To the extent that you have east-west exposure, there are remedies of course. The first order of business is to minimize those sides. Then, keep the windows small, use low solar heat gain glass, and put up some form of external shading.


The Strawbale Folks have it right. Surround your place with a foot of grass. If you're not sure your neighbors will put up with it, well, okay, then stuff your walls with fiberglas. Nasty stuff -- not the kinda Glass I'm talkin' about here. Or, you can surround your place with foam. Foam, grass -- it's all the same to me.

Let's go over this again. Where do you put the grass? On the outside, folks. Like, the grass is greener on the other side. You know that. Now just apply what you know.

For example,


You probably think I'm promoting natural gas. Well, sorta. The gas I'm talking about is very natural.

Now here's the Philosophy 1A question for you: What is the most important thing in life? You've got it,...


Yep, the very best and your favorite gas is air! Trust me. Even the Breatharians agree: Air makes for a Really Light Lunch.

That's cheating!
So if you're going to spend time inside a building, you will want to be thinking about having a goodly supply of this gas formulated and set aside just for you: 80% nitrogen, 20% oxygen, a few other exotic and rare gases mixed in. (Check with your local chemist if you have any questions about the percentages to use.) Poke a hole or put in a vent someplace. Better yet, do a systematic job of ventilating, using natural convection. (Coming right up. See below.)

So where do you put the gas? On the inside, folks. It helps your breathing. Then, like I mentioned, poke a hole in the wall so you can pull in some fresh every day.

Now one more thing: Hot air rises. (Remember?!) Watch what we can do with that!

Trombe wall circulation Getting down to the nitty-gritty,


This is the one that tricks people. Everyone knows that adobe houses are really cool. They forget that they can be really cool in the winter too. That's not the idea. The idea is to put the mass where it belongs.

Sunday Mass
Not that kind of Mass, silly!
But where do you put the mass? On the inside, folks.

Keep your cool in the summer, not in the winter.

Some like it hot. Especially in the winter. So how do you do this? But where do you put the mass? On the inside, folks.

Now, this is like rubbing your tummy and patting your head at the same time: You gotta combine the Grass part and the Mass part together into one comprehensive cohesive whole. So you bought this beautiful old brick house, right? AND the neighbors all have brick houses too, right? You put the Grass on the outside and the Mass on the inside.

"So you're going to cover this beautiful old-fashioned historic building façade on the outside with what?!"

Okay, I admit this 4 donkey stuff isn't for everyone. Just if you want to be comfortable.

I hate forced air heating. It stirs up dust, makes a lotta noise and takes a lot of energy. So, tell you what: If you treat your farm animals right, you get to put a layer of that phoney brick stuff outside the grass on the outside. But remember, I didn't recommend it. You didn't hear it from me. I recommended a thin layer of something like plaster covering your protection from the world outside.

Okay, now let's go over this again: Glass Grass Gas and Mass. Where do they go?

Glass On the South Side. (Almost tricked you there, didn't I?!)
Grass On the OutSide. (Even if you use it to cover your Glass)
Gas On the InSide and on the OutSide. (In with the good air; out with the bad air.)
Mass On the InSide. (No fair swallowing your ski parka!)

See how easy?! All you have to do is consult the 4 donkeys the next time you build or fix-er-up: Glass Grass Gas and Mass.

Weaving it all together, here are some examples of all the pieces assembled in one place ...

Oh, one more thing: if you want to impress somebody and use bigger words, here you go: Fenestration (that's from the French, you know, fenestre means window) Insulation Ventilation and Massification. (That last one's a stretch, but anyway, what can you do? It's just one of the limitations of language.)

This is the start of a very scientific article by Ron Swenson

updated 2005 September 6