Greenwashing is the practice of describing a product as environmentally friendly when, in reality, it’s “green-ness” is highly debatable. Compact florescent bulbs are one example. Yes, they use much less electricity than incandescent bulbs, but they are made with mercury and must be properly recycled and almost require a hazmat cleanup if broken. Bamboo flooring is another example. Bamboo is a renewable grass that grows quickly vs. local oak and maple trees, but because of its popularity, some Chinese companies are clear-cutting forests to plant it, using child labor to harvest it, and then shipping it via huge container ships thousands of miles across the ocean. Green? Maybe, maybe not, it depends on your definition of green.
Enter solar hot water heating. Way back in 1977, I entered a science fair in Pittsburgh with a model solar house. It was a crude little thing that pumped water up to the roof, dripped it down over black corrugated metal, returned it to a large tank surrounded by rock in the basement, and, if I remember the resulting heat gain, would eventually coddle the home’s occupants. It proved a point, though, that you could indeed get lots of energy from the sun for heating hot water. I won a couple awards, too.
Solar technology has come a long way since then, but it still works on the same basic concept. During the design phase of our house we left open the possibility of adding a solar hot water system to provide our hot water. In North Carolina, with a good southern exposure, solar can easily provide 100% of your hot water needs, even in the winter. The cost for such a system? Our architect has a saying, “How much can you afford to save?” What he means is, how much money are you prepared to spend now to save money in the future? A typical hot water heater, installed, is about $300. The average annual cost to heat water for a two person household is $400. A solar system that would provide 100% of our hot water would cost…$6,500 before tax credits and $3,400 after tax credits. Is it worth it to spend $3,400 now to save $400/year for the next 20 years (the expected life of the system)? Payback would be in 9 years. After that, hot water would be free, essentially saving $400/year. Not bad. If you assume that the cost of energy will continue to rise and/or you believe global warming is real and caused by pumping CO2 into the air then going solar looks even better. I’m not ready to commit, just yet, but it does appear to have potential.
Now, to the greenwashing. When I talked to the solar salesman he said that he would also quote a system that had an extra solar panel, an extra tank, and a “booster coil” that would go in the cold-air return duct of our furnace. In the winter, once our water heater was at the right temp, the excess hot water from the solar panel would be pumped into this “booster coil” to preheat the air and, ultimately, reduce our home heating bill. The theory is, don’t throw away the excess heat; dump it into your house. The cost for these add-ons: $4,000 before tax credits and $2,000 after.
If you’ve read the book Blink: The Power of Thinking Without Thinking you know all about how we make snap judgments. Our brains can work through thousands of criteria and make a decision without us realizing it. Sometimes you just know the answer without knowing how you know the answer. I was dubious that this booster coil thing was the real-deal. It just sounded hokie. So, I asked him, politely, to PROVE IT, send me the calculations that will show how many BTUs this thing would actually put into our house. I figured, hey, you’re selling it, you must know if it works.
A couple days later he emails me a page of calculations and a long disclaimer saying that they had to make lots of assumptions about our hot water usage, daily temperatures, furnace efficiency, etc. Fine, I would think that these should all be pretty well established numbers, but, whatever. So, what was the final answer? Each year the booster coil would save us 421kWh of electricity. Wow! Four hundred twenty one thousand watt hours! That’s a lot of electricity, right? Ah, no, not so much. In North Carolina (and most of the US) the average cost per kilowatt hour is 10 cents. So, the average net savings would be a whopping $42/year. A $2000 investment to save $42/year!? Payback would take over 40 years! To put it in perspective, I ran these numbers: If you replaced just 5 75-watt incandescent bulbs with 23-watt CFLs at 5 hours/day you would reduce your annual energy use by 475kWh. For $20 in bulbs you would save slightly more energy than you would by spending $2000 for this booster coil. And, I’d be willing to bet that there is way more energy spent and carbon emissions produced in its raw materials, manufacturing, transportation, and installation than will ever be saved by its use.
Mr. Solar Salesman and I had a long talk. He’s a very passionate environmentalist. I’m a skeptic. After an hour of discussion we basically agreed to disagree. He did concede that the booster coil might not make sense for us (I can’t figure how it makes sense for anyone) but he feels that we should all be doing whatever we can to save the planet – replace the bulbs and get the booster coil. I think you need to look at the big picture and consider the feasibility and practicality as well as the costs, especially the ROI. Valerie put it more succinctly: “If someone came to you and said they had a small black box that would sit in your back yard and would power, for free, five light bulbs for twenty years, you’d probably be intrigued. If they told you that it costs $4000 ($2000 after tax credits) you’d tell them they were crazy.”
Solar hot water probably meets my bar. A solar booster coil for whole-house heating—that’s Greenwashing!
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