Tuesday, January 29, 2008


Anyone interested in passive solar design has to read up on windows. Most modern windows focus on energy efficiency in terms of heat retention. You can buy an energy star rated window for a northern climate like mine; but, mysteriously, the window performs poorly in terms of solar gain because the coating blocks much the of transmission of energy through the glass. So when it's sunny and 10 degrees in the middle of January, you'd have plenty of light but little in the way of solar gain. When designing a house that takes advantage of heat gained from south facing windows, it would be absolutely foolish to install a standard low-e window. On the other hand, double pane windows without a coating perform very well in terms of solar gain but don't do well with heat retention when the sun goes down. Thermotech Windows' web site is a good source of information on passive solar glazing. (Their triple paned windows sound top notch for a passive solar house.)
There are other glazing options out there. You just have to ask the manufacturer what's available. Marvin, for example, offers a glazing by Cardinal Glass called Low-e 178 that would work well with passive solar design, but it's not listed in their catalog and the local dealer in Blue Hill, Maine, had never heard of it. Andersen, however, does not have a glazing that fits passive solar requirements. (Unless, you buy standard double paned, uncoated windows and then go through the process of insulating them at night.) Bonneville Windows offers an AFG glazing called Comfort Ti-PS with a suitably high solar heat gain coefficient.
So what you look for in a passive solar window are two factors. The first is U-value which should be around .3 or less; this is the number relating to how well the window performs against heat loss. The lower the number, the better the performance. The second is the solar heat gain coefficient (SHGC) and this should be around .6 or higher. The higher the SHGC the more solar energy is allowed to pass through the glass to heat the space.
At this point we're leaning toward Marvin for our windows, the jury's still out.

Sunday, January 27, 2008


This might be a good time for an overview of the project. We're building a passive solar house with about 1800 sq ft of heated space. It will look like a traditional gable ended Maine barn with a shed addition that wraps around three sides. Simple to design. Simple to build.
In addition to living space, Michelle will have a small office on the second floor, and the kitchen will include a small bakery with a wood fired bread oven for me. If all goes as planned, we'll both be working from home.

The first floor will be a stained concrete slab (haven't decided on color yet) which will serve as a store of solar heat. Whatever the sun doesn't provide will be made up with a wood stove or, if we're ambitious, a masonry heater. A solar hot water system is going on the roof, and we're hoping to incorporate a grid tie-in solar electric system if our money doesn't run out too soon. I'm hoping that the combination of a highly insulated tight building envelope and good passive solar design will allow us to heat the house with about one cord of firewood (about $250 if I don't cut and split it myself).

I hope to start forming the foundation soon. I'll be pouring a frost protected shallow foundation. It's essentially a short frost wall (16" below grade, 8" above) that's frost protected with rigid foam insulation applied to the outside. It works because heat from inside the house works its way through the slab and protects the ground under the frost wall from freezing. This is also commonly referred to as an Alaskan slab. It's less expensive than a full frost wall and the excavation can be done will a plain old shovel or, if I'm feeling lazy, a small rented backhoe. These types of foundations have been in use in Scandinavia for decades with success. The depth of the frost wall (16" max, 12" min) below grade and the placement of the insulation is determined by how cold it gets on average. On the coast of Maine you can get by with a 12" below grade with 1" of rigid insulation applied to the outside.

I'm hoping to use little if any plywood in the construction of the house. Around here locally milled #4 pine 1x12's are less expensive than plywood and do a good job at sheathing when fastened diagonally across the studs. (The frame will be stick built with 2x6's.) Same goes for the subfloor on the second floor. If there's any place I might use plywood, it's to sheath the roof. The exterior of the building with be covered board and batten style with #4 boards as well. Very barnish. A blending of classic lines and modern building technology. To get a basic idea of what the exterior of the building will look like go to http://www.kaplanthompson.com/barndoorsopen.php


Our excavator is getting a letter in the mail tomorrow. Our phone conversations have been less than productive and I keep missing him on the site. It's not that I think he's dishonest or trying to screw me. He just doesn't listen to what I tell him. It's as though he's there putting a road in for himself and takes direction from no one. I understand that what I'm asking him to do is out of the ordinary. His typical customer would not rent a backhoe to run their own underground power. Or spend a few days with a wheel barrow and shovel spreading topsoil when an excavator could do the same work in a couple hours. What he doesn't want to hear is that I need to do some the work myself to save money. I'm not asking him to do the same work for less. I'm asking him to do less.
His quoted prices for jobs are rounded up to the nearest thousand as though he doesn't want to bother himself with details involving numbers with fifties in them. Perhaps I would have been less likely to question the price for the septic system if it had been $9950 instead of a clean $10,000. But having had a septic system installed in the past, I knew that within that 10 grand was perhaps $500 for seeding and mulching-- something I can most certainly do myself. I knew that he would have a significant sum assigned to bringing in roughly 25 cubic yards of topsoil and spreading it over the top of the septic system-- topsoil that we already have on site following the construction of the road. Or perhaps standard procedure here would be to take away my topsoil and then sell it back to me. But details like this would not involve round numbers in the thousands. Maybe, like Bush, he doesn't do nuance.

Thursday, January 24, 2008

Staying awake

Thanks for setting this up for me, Michelle. I very well could become an obsessive blogger if I could manage to stay awake past 8pm. Last night I fell asleep after reading a story to Chloe and Hazel. Probably around 7:30. Woke up at around 11 and then obsessed about the site work in progress at the new place until maybe 3 or 4 in the morning. At one point I thought I should just get up and go to work at the sail loft. Sleep prevailed.
This blog is going to catalog the building of our new house on Sis Porter Rd in Sedgwick, Maine. We're starting from scratch. Some trees have been cut down. The road, all 700' of it, is going in now, and the septic system will follow. Then all we need is some favorable weather beginning some time in March when I quit my job and become a full time home builder.

Michael has a blog!

I'm probably not going to be allowed to add anything to this site after today, so hello and goodbye. Michael could become an obsessive blogger and we'll end up fighting for time on the computer. Only time will tell.