GREENer HOUSE

The July issue of Real Simple magazine is now off the newsstand. So in case you missed it, I am reprinting my article about green renovations. The editors asked that the information be presented  as a series of questions for the various contractors that might work on a home renovation. I couldn’t really do justice to any of the subjects covered in that format and the space allowed, so I will try to expand upon some of them in future posts.

Crumbling house prices and economic jitters have convinced many homeowners that it’s safer to adapt what they have to what they need, rather than jump into a shaky housing market. But can a renovation help your house adapt to the planet as well?

Throwing a few photovoltaic solar panels on the roof won’t make your home green. And environmentally sensitive architects have moved beyond the singular obsession with energy efficiency. The catchphrase of green building in the 21^st century is “embodied energy.” How much fossil fuel went into the bricks, cement, steel and glass that make up your house? What quantity of greenhouse gases is your home responsible for even before you switch on the first light? For some houses, the embodied energy of day one will exceed the sum of a few decades worth of electricity and gas bills.

Building in harmony with nature means working with the local climate, local suppliers, and even local soil. There is no one-size-fits-all solution. Instead of waiting for easy answers, start with the right questions. And if a contractor stares blankly at the ceiling in response to your queries, you may want to look for someone with greener credentials.

Architect:

How earthy can our house be? Green architects agree that adobe, cob and rammed earth are wall materials of first choice for low embodied energy. An architect who has worked with them will know whether they suit your project. The biggest concern: banks will not approve a bond for new structures supported by such raw materials. A home renovation, however, may be able to get financing.

Can we aggressively pursue passive solar? The right combination of windows, walls and floors can supply most of your heating needs in sunny South Africa. But a large roof overhang is vital to keep the high summer sun out. If your architect cannot calculate the ideal overhang based on your latitude, orientation, roof pitch and height, find another architect.

Can we build around a wood stove? If you have a local source of sustainable wood, such as suburban tree fellers, a closed-combustion wood stove is the greenest way to heat. But with all of your warmth concentrated in one spot, careful designing is needed to help the heat reach colder parts of the house. Keeping the stove central to an open plan but away from any double-volume ceilings is a good start.

How can our home use nature’s air conditioning? Your architect should know how to take advantage of prevailing winds. Low windows on the cooler, south side of the house can draw breezes to force out summer heat from high windows on the north side. Drain the pool of heat on your ceiling with small, high windows that you can leave open all night without worrying about cats or cat-burglars. Transom windows aid the flow between rooms. Trees or shutters can shield western surfaces from the afternoon sun. Don’t let some sweet-talking salesman convince you into electric air-conditioning until you’ve given nature a chance.

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Since the issue of Maverick containing my Solar Photovoltaics vs. Diesel Generators article is off the newsstands, I can now publish the article in full on Greenerhouse. Enjoy:

Bringing Back the Light:

Diesel vs. Photovoltaic

It began with an email. My brother-in-law asked me, the family’s resident green guru, to weigh up the relative merits of diesel generators vs. solar power.

Load shedding is clearly driving him to distraction. Computers are crashing in his home office, and he has scrambled to reschedule meetings of 30 and 40 people to stay out of the dark. He wants to know that the power will be there where he needs it, when he needs it. “I’m looking for a complete solution, and I don’t want hassles,” he told me, admitting that he was close to choosing the diesel route.

But he also knows that his green credentials need some buffing since he traded in his Honda Jazz for a Land Rover Discovery last year. Is solar electricity an affordable alternative?

Until the beginning of this year, the answer to his question would have been simple: In South Africa, solar cells may be virtuous, but they don’t pay for themselves. (Solar hot-water panels do pay for themselves, but you can’t run your PC on hot water.) Even the national sales manager for Sanyo photovoltaic panels in South Africa, Win Kurzyca, says, “it doesn’t pay me to put 10 of these on my roof—even at staff price—instead of paying 32 cents a kilowatt hour for electricity.”

But suddenly everything has changed. In fact, the question has changed. My swaer is not asking whether photovoltaic panels pay for themselves; he wants to know whether solar electricity is competitive with diesel-generated electricity.

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I cannot yet reprint my article on solar photovoltaics vs. diesel generators from Maverick magazine as long as the issue remains on the newsstand. But I can share a  few thoughts from what I have learned while reporting the article:

Prepare Ye the Way of the Panel. For years we’ve been promised that photovoltaic panels will come down in price as volumes increase. Well, volumes increased, but prices went up. Demand rocketed in Germany, Spain and elsewhere as governments made solar attractive financially. Solar-cell factories couldn’t be built fast enough to accommodate the new buyers, so the law of supply and demand took over. This is a temporary situation. As new factories are commissioned, prices will fall to not-yet-seen lows. If you’re feeling flush with cash and impatient, go ahead. Early adopters play a great role in advancing the acceptance of any new technology. But for most of us, it makes sense to wait, especially if the S.A. government implements a feed in tariff—like the one in Germany or Spain—which pays households for surplus solar electricity they feed into the grid.

In the meantime, there is plenty of work to do while getting your home ready for cheaper solar. Photovoltaics produce less electricity than you would expect. They belong in houses that already have low electricity consumption. Replace that old fridge. Install compact fluorescent light bulbs. Invest in a gas stove. Install a solar hot water panels, perhaps with gas back-up instead of electrical back-up for cloudy days. Consider space heating with gas or wood. And if you are doing any remodeling, plan a space in advance for batteries and an inverter. They need protection from the elements and ventilation, preferably in a location close to your circuit board.

It’s Your Health, Too. Burning more diesel is not just bad for the planet, it’s bad for you. Diesel fumes are known cancer-causing agents. Would you want your neighbour to idle his 1979 diesel Land Rover Defender in your driveway for several hours a day, spewing carcinogenic fumes toward your family? Running a diesel generator is no different.

You Get What You Pay For. People are always telling me that generators are cheap. And to look at the advertising inserts from D.I.Y. stores, you would think so. But some of these generators do not even have voltage regulators, leading to blown TVs. Even better generators with voltage regulators can create brief surges that are harmful to sensitive equipment. Seamus Finnegan of Northern Technologies SA recommends two layers of surge protection to protect against electrical current spikes as well as an uninterruptible power supply to keep computers operating during the lag between the beginning of load shedding and the start-up of the generator. “We see a lot of damage done by generators,” say Finnegan.

Heads Solar Wins, Tails Diesel Loses. Okay, maybe I’m biased, but diesel has problems under both scenarios facing South Africans. If load shedding becomes a serious regular occurrence, then the fuel expense begins to eclipse the upfront capital expense, and solar becomes more attractive financially. If Eskom gets its act together and load shedding ends, anyone who opted for solar still has a source of free, green energy. Those who bought a diesel generator are stuck with a rusting eye-sore.

The latest issue of Maverick magazine, which is arriving on newsstands this week, includes an article I wrote comparing diesel generators with solar photovoltaic panels. The point is that solar cells are normally considered pricey, with little hope of paying for themselves in the near term and maybe not even in the long run. Load shedding changed all that, however, because many South Africans are now shelling out tens and even hundreds of thousands of dollars for diesel generators to make themselves Eskom-proof. In my article I compare what happens if that money is instead put into generating solar electricity on the roof. I use actual quotes for systems for one house and then run the numbers to see how the two options compare over time.

When this issue of Maverick comes off the newsstand, I will post the article in-full on GreenerHouse. In the meantime, I will share a few insights from my reporting here in the next few days.

Spring, summer and fall, I take pride in keeping the electricity to my geysers off. The water is heated purely by the sun. With a little bit of luck I can even make it through one overcast, rainy day with the hot water stored in my tanks.

But when we were hit this weekend by three successive gloomy, soggy days, I threw in the towel. With the electricity flowing, I sensed an opportunity, however. I had always wondered how much I was saving with my solar hot-water panels. When I installed them, I was making a hundred other changes to my house. Simply comparing my electricity consumption before and after the solar panels won’t answer that question.

So yesterday morning, I decided to experiment. Assured of no sun, I switched off the pump to the panels and recorded my municipal electricity meter reading. [Switching off the pump was essential because even in cloudy weather, solar panels will warm up enough to heat water to a small degree. Waiting for a cloudy day was essential to avoid overheating the fluid in the panels that was not circulating.]

This morning, I ended my experiment and checked the meter again. My household had used 45 kilowatt hours of electricity in 24 hours, compared to 26 kilowatt hours on a normal weekday in recent months. (I monitor the meter rather obsessively.) This means the solar panels are cutting my electricity consumption by approximately 42 percent.

If we have 300 days a year of decent sun, the panels are saving about 5,700 kWh a year. That translates into sparing the atmosphere 5.7 tons of carbon dioxide annually. My financial savings are not quite as dramatic—and not as important in my mind—but still worth noting. At the current Johannesburg charge of 31.18 cents per kilowatt hour, I am saving R1 777 per year. At this rate it will take me at least 20 years to pay back my large and complicated solar hot water system. Simpler systems cost less than half as much and will pay for themselves much more quickly.

Is my 42% saving typical? Dylan Tudor Jones of Solar Heat Exchangers, the company that installed my system, tells customers that they may save up to 50 percent on their electricity bill. Given that my house used to have two electric geysers, I may have cut back that much. I doubt, however, that most people can slice their electricity consumption in half with solar panels. I have a larger-than-average system—3 panels and 600 litres of storage—and my vigilance against wasting power throughout the house means that geysers were using a disproportionate share of the total. But whether a solar hot-water system saves 20, 30 or 40 percent, it is the smartest step a South African can take toward creating a greener house.