Saturday, September 30, 2006

So you want to heat your house with a's how.

As a young teen, I became obsessed with solar power and energy efficiency in general. My mom was the librarian at school, and one of the consequences was that I learned how to find information pretty efficiently. So over the years, I have seen or read about practically every trick in the book to heat a house inexpensively and efficiently. Here's a partial list of topics that I researched over the years.

Geodesic domes, These are visually fascinating, "modern", with all the pizzaz of Buckminster Fuller. They also generally leak and finishing all those funny angles is challenging to say the least. Geometrically speaking, domes present 1/3 less surface area per cubic foot of living space enclosed when compared with more conventional square/rectangular/cubic construction. So, all things being equal, they can be energy efficient if you are willing to put up with a few leaks. The average building inspector, along with his whole department, will likely give you trouble. For a brief time I worshipped in a church like this in Caldwell Texas that had the most amazing acoustics for singing.

Monolithic domes, Made out of cement or Gunnite or Shotcrete and reinforced with steel, cool or weird depending on how I feel that day. They can attain very high levels of thermal efficiency because they minimize surface area and they use a kind of foam insulation that may attain r-6 to r-7 per inch, which is twice what you get with fiberglass. As far as real world performance, we are probably talking quadruple the real world insulating power of fiberglass batts in a conventional building. They are also tornado proof. makes for interesting reading.

Tire houses, This is where you stack a tire, ram full of dirt, repeat 2,000 times. Lots of code issues and not that great for insulation. Poor control of moisture. Vast enormous quantities of labor required.

Adobe houses, Omit the tires, just use the dirt. Lousy insulation, but tremendous thermal mass. They work great in sunny, cool, dry or sunny, hot, dry climates, and just about nowhere else. Vast enormous quantity of labor required again.

Bale houses, or strawbale construction, This is where you stack bales of straw rather like Lincoln Logs or giant bricks. Construction itself goes pretty fast and is forgiving of beginners if the design is good. The have pretty good insulation values, which, coming from me is very high praise indeed. Conceptually, I want to take this to its logical extreme and build a house out of big round or big square bales with wall thickness of four feet or more. In many places, straw is considered a waste product that is difficult to dispose of, so this kills two birds with one stone. Some code problems in some places. I am still very tempted...

Log home construction, Romantic, pretty, but real world r-values are not that great and they require considerable special skills to construct. Finding good logs of the needed size is not a trivial task in most places and it's an inefficient way to use the lumber. You could take it apart and build two really efficient houses with that much wood.

Underground houses, These offer almost mythical energy savings, in the sense that real data that proves their claims is as rare as pixies and fairies. Devotees often exhibit religious zeal for this idea. Building a house underground does lower the Delta-T (the difference between inside and outside temperature) but they are still problematic on several levels. You can get equivalent or better energy efficiency in ways that are cheaper and easier to attain. There is a book called "The Fifty Dollar and Up Underground House Book" that is a cult classic. I was almost a hippy back then.

Berm houses, These are sort of underground and are neither fish nor fowl. Ultimately, there are easier and less expensive ways to achieve energy efficiency.

Cobb houses, The English are crazy about cob, it's the English version of adobe more or less, with somewhat better insulating capacity. In both relative and absolute terms, r-values are not that great.

Stackwall, This has had a big revival in the last 20 years or so. You basically buy a load of firewood logs, cut them into pieces all the same length and lay the logs up like bricks to make a wall 18-24 inches thick. r-Values OK but not great. A million cracks to caulk after the logs shrink. They are both pretty and distinctive. Here's a blog by a guy who did a double wall stackwall house that came out very good on the thermal envelope. He's the exception though and it involved massive labor inputs.

Double Envelope homes, They didn't really save a lot of energy, and if they did, it wasn't because they were double envelope. They were a short lived fad.

Vacuum panel insulation, These are small panels that are almost absolutely airtight and can be installed as insulation They are very much like a thermos bottle. A perfect vacuum doesn't lose any heat by conduction or convection, only radiant losses, which can be controlled. Unfortunately, they are expensive, delicate, and have questionable lifespan. They are not ready for prime time yet.

Active solar heating, tends to be fabulously expensive to provide 100% of the heat for you rhouse unless you cut your heat needs dramatically by superinsulation techniques. Spectacularly unsuccessful in cloudy climates like mine.

Drum wall, Make your south wall essentially all glass. Build a heavy frame to support 55 gal drums of water behind the wall. Build an insulating cover for that south wall that you can open and close so that it doubles as a reflector during the day. These work fairly well if you have a sunny climate and you insulate well. They look funny and it is not a trivial task to build an insulated door for the south wall of your house. Completely unsuitable for remodels.

Trombe Wall solar heating, This is another big bank of south facing glass. But now you build a cement wall about one foot behind it to soak up the heat during the day and release that heat at night when you need it more. It sounds great, but without nighttime insulation over the glass it is terribly inefficient because that hot cement wall radiates and convects that heat very efficiently right back out the window. It's also, ummmm, ugly. Take a big huge window and build a black wall right next to it so you can't see out or in through the "window". It is still widely promoted by the way. If you can insulate the cold glass from the hot thermal mass at night and on cloudy days, then they work fairly well, but then it's not really a Trombe wall either.

Passive solar heating, This can range from extremely successful to wildly impractical and expensive, mostly depending on how much they implement superinsulation techniques.

Ground source heat pumps, They are expensive, complex and have a history of durability problems. Durability has gotten better lately they say. They run on electricity, which often comes from coal or nuclear, so those are not huge enviro winners. 2/3 of all the heat from the original fuel gets wasted at the power plant before it ever arrives at your house, so system wide efficiency suddenly doesn't look so great. If you absolutely have to heat with electricity, this is how you should do it. You need a big lot and the backhoe will dig huge trenches everywhere. Superinsulation techniques would allow you to cut the size of the unit by half or more.

Air to air heat pumps, These are only efficient in milder climates. At temps below freezing, they become very inefficient because they have to use electric resistance heat to prevent frost build up. They are also expensive and complex to maintain, and run on electricity.

Ground water heat pumps, Also expensive, complex and requires at least two wells on the property, often against zoning regs to pump water back into the aquifer.

Outdoor wood furnaces, These have hideously poor efficiency, often less than 25%. The manufacturers often imply good efficiency, but you will universally find that they are short on indepent test data. They virtually all smoke (aka pollution) when operated as suggested in the ads. This is deforestation and pollution right in your own back yard.

Superinsulation. This is the best, period. I'm not biased or anything. Really.

So that's a thumbnail sketch of what is available, what works and what doesn't. I will support my wild claims for superinsulation in subsequent columns.

As far as actual progress on the actual house, nothing. Still fixing up the city house. Got about half of my cogenerator transfer switch unwired from the regular breaker box and will finish that tonight.

Finest regards,


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:

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

Tuesday, September 05, 2006

Flirting with burnout?

On the surface, it really seems like I’ve been flirting with burnout. The Critical ToDo list only seems to get longer. Both my wife and I knew moving into this house was going to involve some serious time commitments. Here’s my current work list for the farmhouse:

-Build new exterior walls, just inside present walls
-New gutters and downspouts, along with drainage system
-All new wiring, including 2nd breaker panel and transfer switch
-Install Co-generation system, which I have to custom build
-Build and install insulated 5,000 gallon water tank in basement to store heat as part of co-gen system
-Install wood stove and insulated chimney, which goes through the first floor ceiling, the second floor ceiling and the roof
-Add fill dirt and re-grade around house to provide positive drainage away from house
-Plaster fieldstone basement walls with high strength, latex modified, fiber reinforced cement
-Cut, split, and stack firewood for this winter (very soon, has to properly season)
-Fix garage doors so we can actually park something in there
-Build some sort of temporary or permanent outbuilding to shelter the tractor and “new” Mercedes this winter
-Install 2 new exterior doors
-Fix and/or replace the present propane boiler so we don’t freeze to death this winter
-Winterize tractor, Chinese antifreeze not so reliable and looks nasty
-Add block heater to tractor so I can actually push snow with it this winter
-All new supply plumbing and all new plumbing fixtures
-Add insulation to new exterior stud walls
-Drywall everything
-Make floors level
-Install radiant floor heating system and tear out old baseboard radiators
-And some other stuff, some of which I’m not even aware of yet.

Much of this stuff is time/weather sensitive, so I have been busy like crazy. Several 14 hour days in a row are not uncommon. There are times when I am tempted to think I have bitten off more than I can chew. My regular job consumes 50 hours per week. I’m still remodeling the previous house so we can sell it and not run into cash flow problems. I still pick up used fryer oil from two restaurants that I use for my biodiesel.

I should be biting my fingernails right off. I should be sleeping poorly, I should be very highly stressed right now, what ever that means. Something...

I’m not.

This house feels right. That’s sort of a secular way of saying we believe we are being obedient to the will of God in making this move. Divining the will of God in a specific/personal way is a delicate business, but we think we are on the right track. If God wants me to do this, and I hold up my (almost insignificant) end of the deal, He will give me whatever resources, whatever time, whatever energy, whatever strength, whatever anything is necessary to get the job done. If God is for us, who can be against us?

Git 'er done.


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