Can $1,000 Solar Greenhouses Heat Our Houses? Can They Save Northern Countries From Peak Oil?

Ok, the short answer is no, because solar greenhouses are not going to be powering someone’s commute anytime soon. However, they could just be a big part of the solution to heating homes, which makes up a very large part of total energy use and will take an increasing chunk of the family budget as oil prices increase. To those who say they will be unaffected because they don’t heat with fossil fuels, think again. Solar greenhouses could also be used to grow food, another major chunk of the family budget and also highly susceptible to oil prices.

In this solar greenhouse (not pictured), the homeowners spent $1,000 and their labour to create a simple but very effective solar greenhouse that reduced their heating consumption – for a 100-year-old, 1,800 square-foot* house in Wisconsin! – “…to less than one cord of firewood and about $50 worth of natural gas.” That is remarkable. If it can work there, it can just about anywhere.

This was no high-tech greenhouse, as you may have gathered by the cost, yet it was still highly effective:

All windows were single-glazed, and some of the recycled storm windows we used for glazing were cracked, yet we were able to maintain “frost hardy” vegetables, even with outdoor temperatures in the minus 30’s.

We were able to “harvest” heat from our greenhouse every day that it wasn’t actually snowing, as long as I kept snow from accumulating on the glazed portion of the roof.

With good circulation, the volume of air in a 9 x 30 foot greenhouse is great enough to keep an 1800 square foot house warm as long as the sun shines.

This, by-the-way, was in a house in the city.

Growing bananas in the Rockies

If we got serious about solar greenhouses, the heat return to the house could be increased and so could the varieties of vegetables – and fruits – grown. My personal goal is to have a solar greenhouse capable of growing avocados, as my wife and family are Colombian and love them. Of course, as avocados must be flown in they are expensive, contribute to climate change, and will likely be unavailable as oil prices rise significantly. I have the advantage of living in Victoria, Canada, so should be able to do so easily.

However, even people living in much colder areas of the country can grow tropical fruits in a solar greenhouse. The bananas in this photo are grown in Amory Lovins’ solar greenhouse in Colorado, which he describes as

…the “furnace” for the building. This 900-square-foot space, plus the heat gain from the other windows, lights, appliances, and people, provides all the heat that’s needed for the entire building most of the year.

The heat is stored in the masonry, the floor, the water, and the earth under the house. Because of the building’s huge thermal capacity, heat is stored for months, not just hours.

Heat captured in September may be used in December.

That is remarkable. The Lovins’ building is a much higher-tech solution than the Wisconsin $1,000 solar greenhouse, and has correspondingly greater capabilities. I hope we start investing in this kind of tech soon, or peak oil may leave us only with the low-tech, low productivity option; better than nothing by far, but no bananas.

All heating costs are tied to oil prices

I should close by addressing those who don’t heat with oil or natural gas (also in decline), and may believe their heating bill will be unaffected by rising oil prices. You will. As oil (and natural gas) prices increase, there will be a switch to electricity for everything from heat to cars, driving the price of electric heat up.

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* Note: I believe there is an error in the article when it states that the house contains nine bedrooms. I suspect this should be nine rooms, not nine bedrooms, as it is 1,800 square feet. However, it is possible.

Suggested books if you want to learn more

The books below discuss in much more detail some of the ideas mentioned in this post.

The first book (from left-to-right) is Plenty: Eating Locally on the 100-Mile Diet – something the authors found a tremendous challenge. And they live in Vancouver, where far more can be grown than anywhere else in Canada. They found certain foods were simply no longer available, something that will also happen as oil prices rise. Here’s a telling quote from the book:

Call me naive, but I never knew that flour would be struck from our 100-Mile Diet. Wheat products are just so ubiquitous, “the staff of life,” that I had hazily imagined the stuff must be grown everywhere. But of course: I had never seen a field of wheat anywhere close to Vancouver, and my mental images of late-afternoon light falling on golden fields of grain were all from my childhood on the Canadian prairies. What I was able to find was Anita’s Organic Grain & Flour Mill, about 60 miles up the Fraser River valley. I called, and learned that Anita’s nearest grain suppliers were at least 800 miles away by road. She sounded sorry for me. Would it be a year until I tasted a pie?

The next book is James Howard Kunstler’s The Long Emergency: Surviving the End of Oil, Climate Change, and Other Converging Catastrophes of the Twenty-First Century. Kunstler explains why peak oil is imminent and a problem.

The next two books discuss growing your own vegetables year-round in a solar greenhouse. The second also is recommended by the builder of the $1,000 greenhouse, and has instructions for building a solar greenhouse. It is out-of-print, but you can buy it used or borrow it from the library.