HOME EFFICIENCY | An Affordable High-performance Home: The inner workings

(Left) Paul brushes hoarfrost from the evacuated tubes. Photo: Sandy McNie (Right) Sandy loves her new wood cookstove. Photo: Paul Hearsey

By Paul Hearsey –

A year ago I wrote in TheGreen Gazette about our house-building project here in Horsefly, a project we have spent about six years on. This was meant to take one year, but I’m sure many readers can relate to the fact that day-to-day life can often get in the way of best intentions. We discussed the basic design and construction of this low-budget, high-performance home, so here we will talk about the active solar and water features we installed.

First, just to remind readers, our home is an off-grid passive solar design: that is, very heavy insulation and triple glazed windows allow the sun to contribute to the space heating. A wood cookstove is our sole source of heat beyond the solar component. We reluctantly replaced the beautiful antique we had recently restored with a modern airtight from Italy: a La Nordica Suprema ordered online through Obadiah’s Woodstoves in Montana. This new cookstove is incredibly efficient, using perhaps one third the wood our old stove did. Small, modern, airtight cookstoves for small homes are difficult to find, so we had to look to Europe.

On the south-facing roof are three solar water heating panels, each holding 20 evacuated tubes, which collect the sun’s heat. We run non-toxic propylene glycol in the system so it can operate in sub-zero conditions. The glycol transfers heat to a stainless steel heat exchanger, which transfers heat to the water in our twin 60-gallon water tanks. The tanks are just large enough to carry us through a few cloudy days, and are heated in sequence. Three panels are a lot, where only one would ordinarily do, but we built heated floors in the bathroom and mudroom and they can use a lot of hot water. Everything is housed in a little closet-sized space we jokingly call the boiler room.

None of this was terribly expensive: the solar panels from Seabird Solar in Agassiz costing about $800 each. Affordable heat exchangers, pumps, and miscellaneous hardware were purchased online from all over North America and Asia. We also installed a stainless steel water heating loop in our wood cookstove.

So far, our setup has been working very well. It has been running for five months and produces a great deal of hot water. Of course, to produce adequate hot water in the winter we produce too much in the summer, so an automatic valve diverts hot glycol to a forced-air heat dump when necessary, dumping hot air outside. I plan eventually to build motorized covers over the panels, so we can reduce hot water production simply by shading them. We continue to make significant quantities of hot water at minus 12-15 degrees C (amazing!), and are still experimenting to find at what temperature this system can no longer function. Again, so far so good. We’re very pleased.

The house is wired for 120/240 VAC, plus 24VDC in some key areas. In the late winter we will be setting up our twelve 230-watt Canadian Solar photovoltaic panels on a fixed (non-tracking) ground mount we built some time ago. This will give us 2.75 kilowatts, enough to run our home fairly comfortably. The low voltage outlets are for reading lights and a few essential boiler room components, which means that at night the Magnum four-kilowatt inverter can go into sleep mode, conserving power. A Tri-metric panel and Magnum panel on the living room wall will allow us to monitor the electrical system remotely. And finally, we have a six-kilowatt Kubota diesel generator in a nearby outbuilding; we don’t expect it to get much use. We bought a SunDanzer super-insulated chest freezer from Earthright Solar, which will run directly from our battery bank, again allowing the inverter to sleep. Because solar is getting to be so affordable we bought the most efficient all-fridge we could find at the Williams Lake Sears store, rather than buy a very expensive off-grid fridge. It is twice as efficient as our old fridge in the cabin and our solar is sized to run it quite easily.

Sandy loves her new wood cookstove. Photo: Paul Hearsey

Sandy loves her new wood cookstove. Photo: Paul Hearsey

Managing electrical consumption is important in an off-grid home. We originally outfitted the house with compact fluorescent lamps. Then the price of LED lamps began to fall. We removed our CF lamps and installed LEDs throughout the house. My wife, Sandy, likes to be able to control lighting levels so I put dimmable LED lamps in a few places, like over the dining room table. I began this lighting project by importing lamps directly from a Chinese manufacturer, but prices continued to fall. My favourite LED lamp supplier now: Canadian Tire. Both Rona and Home Hardware have a decent selection, too.

One interesting feature of this home is an ultra-high efficiency Hennessy and Hinchcliffe toilet from Central Builders Supply (Home Hardware).

The Proficiency is a well-secret, it seems, because no one we know has ever heard of it. This is a very good Canadian product that uses only three liters per flush. No big flush, little flush buttons. It was the first three-liter flush toilet in the world when it was first released to the market in 2009. We bought a prototype to try in our cabin back then, and can’t recommend it highly enough.

I checked just recently and it retails locally for $293. By the way, there are now seven models to choose from, some taller, some more stylish. Our well water has a good deal of iron with a touch of arsenic (very common in the Cariboo) so we run it through a treatment system. This means our water has a cost attached to it, so anything we can do to reduce consumption is a no-brainer. The new toilet was a big help.

We looked at ways we could reduce our water usage further. Rainwater was an obvious choice, so we placed a ground gutter around the house to collect water off the roof. This is a gravel-filled trench, a very wide footing drain of sorts, which guides rain and meltwater away from the foundation, then pipes it to a 3200-liter underground tank. This runs the toilet. Once the tank runs dry, in January we expect, the toilet can be switched over temporarily to well water until the spring melt. Since we will not be using rainwater for anything else, we don’t need to sanitize it with an ultraviolet sterilizer—just a simple run through a sediment filter to protect the small Shurflo RV-type pump.

You might wonder if gutters and downpipes wouldn’t have been easier than a labour-intensive underground collection system, but I’ve seen what heavy snow can do to gutters. We decided to go with something far more rugged and permanent.

Everything we built was done with limited funds. Overall, I think we did well. But I can think of a few things I might do differently if I could go back. It would have been smarter to dig a partial basement under the bathroom, where a much larger single hot water tank could have been set up. With enough volume and insulation we could have stored hot water to last a week or more. The solar hot water panels could have been installed vertically, either on a ground mount close by or on the south-facing wall of the house, under the overhang. That would have kept snow off the tubes, and decreased summer over-production. One more thought: if solar photovoltaic panels fall in price far enough it will become more economical one day to heat water with solar-generated electricity. In the meantime, we may add another 1.2kW of photovoltaic panels, for a total of four kilowatts, within a year or two. The prices are attractive and more power generated makes us that much more independent.

 

Paul Hearsey and Sandy McNie live in beautiful, snowy Horsefly. Their interests range from farming and gardening to building design and all things solar. This year they hope to find time to work on their ‘new’ 1951 Massey Harris combine harvester, all the way from Alvena, Saskatchewan (pop.55). They welcome feedback, questions, and visits. Email them at parsleybed@netbistro.com

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