Friday, September 22, 2006

How to heat your house with cats.


My apologies for my tardiness. This is a big topic and I finally realized it’s just impossible to give it proper treatment in one column. So we will attack it piecewise.

How to heat your house with cats, or, in our case, a rabbit.

Most folks have noticed that energy has gotten expensive lately. This is true for gasoline, propane, natural gas, home heating oil and so on. It is also true that most folks do not expect this trend to be reversed any time soon, if ever. This issue has been in the media a lot lately in the form of Peak Oil theory, as originally described by King Hubbard. He was a brilliant petroleum geologist and geophysicist. For those who are curious, here’s a nice summary that avoids most of the hysteria associated with this idea:

http://en.wikipedia.org/wiki/Hubbert_peak

Some of the more extreme believers in this theory think that this phenomenon will cause 90% of the people on the planet to die in the next 20 years. Famines, wars, the whole end-of-the-world-as-we-know-it idea. Others believe in the “soft landing” theory, which suggests that this will just require some modest economic and lifestyle adjustments while we make the transition into renewable energy.

At this point, I have not entirely made up my mind which camp I am in, and for our immediate purposes, it doesn’t matter. The key issue is that energy is exquisitely unlikely to get cheap again. That doesn’t mean prices can’t wiggle up and down, but it will never go down very far for very long.

So, what shall we do about all this? I’m glad you asked because there’s a lot we can, should and must do. Today, we will learn about superinsulation techniques and someday, you will have the opportunity to put them into practice. Be warned, there will be resistance. But we will be prepared for it.

The people who build houses for a living are a pretty conservative lot. They like doing it the same way they have done it for decades. This will cause problems for you. Chances are pretty good that you will buy or build a house in the next ten years. Chances are also pretty good you will do some kind of remodeling on this house and/or the next. If you go along with the conservative building trades and the advice from the big box lumber store, this will cost you potentially many thousands of dollars in extra heating and cooling costs, and more importantly, you will waste irreplaceable energy resources.

Back in the day when coal was seven dollars a ton and home heating oil was ten cents a gallon, it just didn’t make economic sense to insulate your house. You would practically never recover your initial investment. Shoot, before the Second World War, residential insulation as we know it barely existed. Why would you bother when you could just put in a big ol’ furnace and shovel a little bit more coal. Everybody did it, and it was less work. Nobody really thought about the long term consequences. That was an unfortunate mistake caused by a short term and very narrow economic view of the situation.

Today, we just don’t have the luxury of being wasteful with non-renewable resources. Plus, I’m frugal. I am bothered by waste and I think it’s wrong, sinful even. I believe in stewardship. As a Christian, that means the resources aren’t really mine to waste anyway. God owns all the coal, all the oil, all the trees of the field, all the uranium and all my money to boot.

He loans all these resources to me and then tells me to do a first class job of taking care of his planet. Leave some for the next guy. Leave some for your great grandkids. Love your neighbor. Even love your enemy. He’s very clear on that. So that’s the motivation to conserve energy and resources. Now let’s talk about how to accomplish this.

Insulation is God’s gift to stewards like you and me. To get the basic idea about insulation, we have to talk about r-values. They are an objective measure of the ability of any particular insulation product to slow heat loss. The bigger the r-value, the better. We’ll deal with all the math and the subtleties in a subsequent column, but the short version says that if you double the r-values in a house, it suddenly takes half the energy to heat it.

This is where you will butt heads with your contractor. The vast majority of house builders only build two kinds of wall systems. For anything except the rich people who demand those new “energy efficient” houses, they build the walls using a single layer of 2x4’s. This is a very bad idea, because it physically limits the amount of insulation you can cram in there. For fiberglass, the most commonly used insulation, that means you theoretically get r-13. And the so called energy efficient model would use a 2x6 stud wall rather than the 2x4. That allows for a modest increase to approx r-20.

The hitch is, even this “energy efficient” model is not that well insulated when you consider the whole wall. Those r-values refer only to the insulating power of the material itself, not the whole wall as a finished product. The primary problem is that wood is not that great an insulator (r-1 per inch). With studs every 16” which is the standard, plus all the extra framing that is needed around corners, doors and windows, wood actually makes up 15-20% of the area of the wall. So effective insulation levels are right back to the underwhelming range of r-16. We need at least r-30.

To properly conserve our energy resources (which is a mandate from Almighty God don’t forget…) we want to install vast amounts of insulation into our walls. Almost magic things happen when you achieve r-30 to r-40 levels of insulation. Annual heat bills can be about the same size as monthly heat bills in a conventionally built house. Some heat their entire house using a largish water heater as a boiler for radiant floor heating or hot water baseboards. Conventional furnaces are often three times too big/powerful.

The tiniest EPA rated wood stove you can buy can successfully heat a 3,000 sq. ft. house with modest amounts of wood. Attaining this level of energy performance will require different kinds of insulation, or different kinds of wall framing systems, or both. Since it takes so little heat to keep the house comfortable, heat sources that we don’t ordinarily consider suddenly make a real difference.

Things like refrigerators, humans, light bulbs and cats all produce heat as a byproduct. Even the sunlight coming through the east, south and west windows can now make a significant contribution to making you comfortable in the winter. Taken together, these ambient or bonus heat sources may provide all the heat you need in the spring and fall. Who knew that you could make a passively solar heated house just by strapping enough insulation on there?

Your average general contractor will be resistant to most or all of these ideas. They will claim that nobody does it that way. They will say that it is very expensive. I had more than one contractor tell me it was outright stupid and that this was a big waste of time and money, and that ultimately it wouldn’t even work. They were all very wrong.

I would argue that all the opposites are true. Lots of people are building superinsulated houses. A Google search for “superinsulation” produced 38,000 hits, so somebody must be doing it. They are not that expensive initially and they are overwhelmingly less expensive in the long run. It’s true that you will spend more for framing and insulation, but you will need a much smaller furnace and probably no central air at all which offsets much of the cost.


As an example, I built a superinsulated house in the late 80's in Canada (pictured at top). The walls were 16 inches thick. We heated with propane (plus all the bonus heat!). When I first got the propane tank delivered, the propane company wanted to put me on automatic monthly fill ups during the winter to be sure I didn't run out. I commented that it was unlikely that I would use up even a single tank over the winter and they all laughed. It turned out to be true though, using approximately 1/3 of the propane used in a similar sized "energy efficient" house, and a tiny fraction of the propane needed by an old drafty farmhouse of similar size.

As a rule, these houses are highly successful and very comfortable to live in. It would almost be worth the extra cost and effort just for the amazing quiet that comes from thick well insulated walls. This concept is definitely worth pursuing since this strategy will save staggering amounts of energy over the lifespan of the house, and likely save you a pile of money as well. We will go into considerable detail over the next few entries about how to do this.

Most importantly, God will smile approvingly at your efforts to take care of His creation.

Finest regards,

troy and christina

4 comments:

PeakEngineer said...

Good post, neat site. I like your perspective on passive heating from what's already running in the house -- with good enough insulation, it all stays in.

entirelysimulated said...

I'd never seen your Canada house. Looks great. Good lesson, professor!

superclosetnerd said...

Not sure if I want to user blogger or not, i like the way your site looks and it is free. I want a blog for my site but just can't decide. My site if ya wanna look... chimney

Elliott Russell said...

Great Post! I have often been thinking of such things, and frankly i have no idea what camp i fall into (end of the world, or difficult transition with energy) but i am concerned concidering where i am in life (still a student at university)

All that said and done, it is always a pleasure reading another believers blog, who also thinks of stewardship on a global scale :)

God Bless
Elliott
PS i dont use Blogger :S so if you care to toss your feedback my way please do www.elliottrussell.ca

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