Designing houses to fit the future
June 9, 2009 · 10:59 AM
by Robert Graef
Housing starts are down. Real Estate sales are flat. It might be a good time to sit back and think about how changing conditions could affect home designs in the next building-boom. Things won’t be the same. Like the auto industry, the home-construction industry faces issues that may very well alter the products they’ll be marketing to my children or grandchildren.
So how might a next-generation home be different from what we live in now? For one thing, we may have reached the limit of big-ness. When comparing how much a family actually needs with what homeowners yen for, the difference may be measured in thousands of square feet. Grandpa and Grandma raised our parents in little 2-bedroom cottages, thanks to mortgages backed by WWII’s GI-Bill. Most didn’t exceed 1,200 square feet but they worked just fine. One bathroom and a single garage. You can spot them by their squareness and lack of eaves.
But that’s looking backward. Today’s challenge is to look forward, seizing opportunities that are just unfolding. Denmark’s Samso Island did that, taking advantage of constant wind to make the islanders not only independent of fossil fuels but able to sell surplus energy from their wind turbines. Marysville and Arlington might not be as windy as Samso but there are steps that every climate and latitude might employ to make better energy-misers of the next generation of houses.
We need to look up, right through the clouds to find the solution to our energy needs. The sun is there and ready to deliver energy whether the sky is clear or cloudy. As a George Harrison song lyric said,
“Here comes the sun
Here comes the sun
It is the brightest light of them all,
Here comes the sun.”
Is solar power reliable? You can’t turn it off! As to intensity, Marysville gets 70% as much solar energy as San Diego, plenty for meeting a host of energy needs. Solar installations aren’t cheap but after penciling in all the costs associated with processing, transporting, burning and cleaning up after fossil fuels, solar turns out to be about a wash. With solar electricity there’s no air pollution, no oil spills, no greenhouse gases and no running up the national debt from purchasing foreign oil.
Now, what does this have to do with new homes? Technology allows us to build homes that grab solar energy when needed or reject it to keep a home cool. Or both. Solar technology enables us to think differently about roofs. Until now, roofs were designed to keep rain out and heat in. Before solar (BF) roof segments could be angled every which way — which seems to be the current fad.
Solar roof construction calls for simplicity of design and sameness of orientation. One needs a broad roof surface oriented and angled to maximize solar harvest. Like the entrances to Hopi hogans that face east, solar homes should face the sun, regardless of which direction streets run or how the terrain lays. Freedom of architectural expression takes a back seat when highest priority is given to harvesting solar energy. Imagine a neighborhood where every roof-slope facing the sun had the required perfect pitch and orientation. Architects say, Booo-ring.
While other parts of the roof might be of traditional construction, the sun-facing panel needs special treatment. Like skylights and chimneys that are notorious for leak-inviting joints, roof-mounted solar paraphernalia has to be installed with an extra measure of care. And roofs should be stout enough to bear the extra weight of wind-resistant solar apparatus plus whoever akes care of periodic cleaning.
The simplest solar gadget is a water pre-heating reservoir tucked into an attic chamber under a heat-trapping skylight. Cold water at ground temperature flows into the reservoir where it absorbs enough heat to minimize work left to be done by a conventional water heater.
A more efficient system requires roof-mounted panels plumbed with tubing containing propylene glycol, a form of antifreeze that is nearly as good as water for absorbing heat. After absorbing heat, the propylene glycol moves through a heat-exchanger that passes the heat to household water. A typical installation in the Marysville-Arlington area would cut the cost of hot water by more than 50 percent.
A more costly but still more efficient option involves a few evacuated tubes the size of bed-posts. Rather than covering a big patch of roof, it takes only a half dozen tubes on a 4x6-foot mount to heat water for a small family. Though solar hot water gives the biggest bang for the installation buck, solar electricity will likely match it for popularity.
While a quarter of a roof surface might suffice for solar hot water, it takes a carport-sized area to generate enough energy for a day’s driving in an electric car. It is like having a gas pump on your roof. Even without the clean-environment issue, electric cars are the future because the cost per mile of PUD electrical energy is only one-fourth that of gasoline. If the energy comes from the sun then you have only the cost of a solar collector to factor in.
Will home owners be willing to trade architectural features for solar efficiency? In other words, is the world ripe for this idea or will it have to wait until energy costs and air pollution reach deeper crisis points?.
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