Thom and Diana Krytofiak with the backyard solar collector that Thom built himself.
I built a super-sized solar hot water system from scratch in the spring of 2010. “From scratch” means with copper pipe, aluminum flashing, wood, insulation, and greenhouse glazing—and no major commercial components.
Why pursue such a crazy idea? The last straw was a local solar expert who warned me in a knowing, parental way that building my own system would be a “gigantic mistake.” “Oh yeah?” said my rebellious and confident inner child, and I never looked back. Here’s how it all unfolded.
Ready-made Systems are Pricey
My wife Diana works in the Sustainable Living department at Maharishi University of Management (MUM), promoting all things green, and she wants us to walk our talk. Although she already has a four-season greenhouse and a Prius, and we have reduced our electricity use about 35 percent by various means, we lacked an alternative energy system for the house.
So I looked into buying a solar hot water system. The price tag was surprising—about $7,000 installed for a system sized to handle just our modest domestic hot water (DHW) needs. With tax credits, the net cost was $5,500.
Then came the breakthrough. I discovered a goldmine online: builditsolar.com, with endless streams of free information on building solar systems. I found that for less money than I’d spend on the commercial system I was looking at, I could build a system with three times the collection and storage capacity.
Because our home is heated with hot water via radiant floors, I liked the idea of a lot of capacity. I wanted to see how much of the sun’s energy we could harness for winter heating, in addition to our DHW. It would take a system much larger than we could afford to heat the house completely, but I was hoping for a decent contribution.
The total outlay for my system, including an occasional hired helper, came to about $6,000. A commercial system of this size would cost upwards of $16,000 after tax breaks. So the upfront savings was a cool ten grand. My labor, of course, was “free.”
Coming Up with the Design
The system I built owes a lot to other people’s designs, although it is different in some respects from anything I had seen. There were no actual plans available online, just detailed descriptions of other people’s systems, illustrated with photos and diagrams. I was familiar enough with basic construction techniques, and confident enough in my ability to learn the rest, that I was sure I could fill in the blanks.
Crowd-sourcing made all the difference. Joining a couple of Yahoo Groups (SimplySolar and SolarHeat—active communities of people engaged in do-it-yourself solar energy), I collaborated with solar experimenters and professionals from all over the country, none of whom I ever met, providing detailed advice of a kind I could not get locally. Just as I owe the inspiration for the system to my wife, I owe the success of its implementation to these dedicated and remarkably generous souls.
Construction
MUM student Sherry Bolden signed up to help me as an intern. She had soldered copper in the past, and in the end we did not have a single leak in over 200 soldered joints. I had a full-time job, and she was in class all day, but we managed to spend an hour or two together most afternoons assembling six 4-by-8-foot solar collector panels. We had some aerobic workouts, hammering grooves into 120 aluminum sheets to fit tightly over the copper pipes. We cut and caulked and routed and stapled, and in the end were glad that there were only six panels to build.
Then the battlefront shifted to our backyard. With cardboard gauges and string, I did a solar site survey to find the best year-round sunny spot in the yard. A farmer friend came by to drill 14 holes. Posts were set in concrete and the support structure built. Insulation sheets recycled from a commercial roof came next, and the six collector panels were popped into place. A trip to Farmtek in Dyersville supplied the greenhouse panels, and pretty soon I had a great-looking wood-trimmed 24-by-8-foot solar sculpture gracing the backyard.
I still had to get the heat into the house. Mine is a “drainback” system, where the water drains back to a storage tank by gravity whenever the pump is off. In climates like Iowa’s, you either have to pump glycol or ensure that no water remains outside when the collector temperatures fall below freezing. Digging a 50-foot trench from the collector to the basement on a raging Iowa summer day left my construction helper and me more or less delirious. That is my excuse—a fried brain—for why, at the end of that day, I wrote on the back of the collector some crucially wrong information, reversing which was the supply line and which the return. That little mistake cost a week of head-scratching when I turned the system on.
Drilling through the concrete foundation was easier than I expected with the right rented tool (and good macho fun). In the basement I had built a rectangular tank out of plywood and 2x4s, lined with heavy pond liner (EPDM) and insulated with 4 inches of foam, holding about 300 gallons. Inside the tank are two concentric coils of pipe. The larger coil holds enough pre-heated water in the pipe itself to handle a long hot shower, so cold city water never hits our propane water heater from spring through fall. The inner coil is copper for faster heat transfer, and supplies heat to the radiant floor in winter.
After wiring the controls and finishing the inside plumbing, it was time to throw the switch. Over the next few days, 300 gallons of cold city water rose to 160 degrees (the maximum I allow), and we were in business. Quietly and automatically, the sun was heating our water.
Challenges and Results
I cannot tell a lie. There were some glitches. The project took longer than expected, and cost more than my original optimistic estimate. But I enjoyed it, I learned a lot, I got the satisfaction of doing it myself, I am passing my experience on to others, and the economics still look like they make very good sense. A “gigantic mistake”? No—so far it has been a gigantic hoot and a very gratifying success. It has run smoothly even through the coldest days of winter.
Seven months of the year or more, the system will supply virtually all the hot water we use for showers, dishwashing, and clothes washing. In the winter, when we get good sun, it contributes nicely to heating the house, while still pre-heating the DHW. I won’t have solid savings figures until a year passes (we went online in August), but so far it looks like a winner, financially as well as environmentally.
You can find all the details of Thom’s solar project at www.krystofiak.com/solar.
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