Last fall, when we had our boiler tuned up for winter, the repairman confirmed what we had long know was coming: our ancient boiler, probably installed when the house was built over 40 years ago, was slowly rusting to pieces. Rather than try to replace it in a hurry before the weather got too cold, we resolved to nurse the old one through one last winter and replace it at our leisure in the spring. So now that the weather has finally (finally) warmed up, I've lined up a series of appointments to get quotes on a new unit. In fact, the first contractor, who showed up today, gave us quotes on two: their standard gas boiler and their super-efficient condensing model. And, no surprise, there's a big difference in cost between the two. If we go with the plain old 83 percent efficient boiler, it costs us $3600; for the super-duper 93 percent efficient boiler, it's a whopping $7600. (We can get back $300 of that as a rebate from the state's Clean Energy Program, but unlike some other utilities, PSE&G doesn't give us anything extra on top of that, the cheapskates.)
Now, the contractor thought the more efficient boiler would pay for itself if we intended to be in this house long-term, which we do. However, based on my calculations, we're talking really long-term. I punched in the numbers on the manufacturer's energy calculator (which I had to use in Firefox, because it doesn't work in Chrome), and it thinks that the more efficient boiler would cost about $208 a year to run, while the moderately efficient one would cost $231 a year. So, if we're saving $23 a year, it would take about 160 years to pay for the $3700 difference between the two. Moreover, even these numbers may be highballing it, since their calculator shows us using 370 therms of gas each winter with our current boiler. Based on my back-of-the-Excel-spreadsheet calculations from our utility bills, our actual energy use is somewhere between 227 and 349 therms per winter.
So the bottom line is that, based solely on dollar considerations, we can't justify buying the more expensive boiler. Which brings me to the dilemma: is it worth spending an extra $4000 (well, $3700 after rebate) just for the sake of doing everything we can to curb global warming?
To make this decision intelligently, I had to ask myself just how big an impact the more efficient boiler would really have on our carbon footprint. Considering how little it saves us in dollar terms, I kind of suspected that it wouldn't be that much. So I found a greenhouse gas emissions calculator and punched in the 30 therms of natural gas that, according to the Weil-McLain site, is the amount we'd save per winter with the high-efficiency boiler. Burning that amount of gas, I found, would produce 351 pounds of atmospheric carbon. Then I calculated our household's current total carbon emissions using this other EPA calculator and found that they come to 13,575 pounds per year. So buying the more efficient boiler would reduce our footprint by an extra 2.5 percent. But given that we already buy carbon offsets every year to make up for the fossil fuels we burn, couldn't we just spend...lemme see here...an extra $1.64 per year on those to make up for that extra 30 therms of energy? I could pay that amount every year for more than two thousand years before it would add up to the extra $3,700 we'd pay for the pricier boiler.
But then, on the other hand, we'll probably have this boiler for at least 20 years. Indeed, if it lasts as long as our current dinosaur of a boiler has, we may never replace it again. And while the 93-percent-efficient boiler may be the top of the line right now, it's quite possible (likely, I would hope) that some time in the next 20 to 40 years, boilers that efficient will become the standard. So does it make sense to get the most efficient one that's available now, rather than risk ending up behind the curve in the future? Then, too, natural gas presumably isn't getting any more plentiful. People don't tend to talk about peak natural gas the way they do about peak oil, but it stands to reason we've got to hit it some time, and at that point, the price of natural gas could increase pretty steeply. So the $23 that the more efficient boiler would save us next winter might end up being more like $50 or $100 or $200 by the time this thing sees its twentieth winter.
But on the other hand (hey, where'd that extra hand come from?), using fossil fuels of any kind isn't really sustainable in the long term. This report from the unapologetically left-wing Center for American Progress concludes that "In the near term, natural gas presents opportunities to reduce carbon pollution" as a replacement for coal, but after that, "there needs to be a swift transition from natural gas to zero-carbon energy." Their definition of "near-term" is no later than 2030, well within the expected lifetime of our new boiler, whichever model we get. So does it perhaps make more sense to save those extra dollars now so that we'll have them to invest in a "zero-carbon energy" method of heating our home down the line, whenever such a method becomes available? (I'm not sure what such a future method might turn out to be—solar? geothermal?—but then, that's why they call it the future.)
I don't know yet what the answer is, and there's probably no point in jumping to conclusions until I've at least seen the quotes from the other contractors. Maybe one of them will turn out to have a high-efficiency boiler that's much less expensive, and the point will become moot. But thinking about it, I can't help feeling like we've made this same decision several times already: with our water heater, with our car, and even with our choice to continue using CFL bulbs until the price of LED bulbs drops. In every case, we ended up opting for the less efficient product because, as Brian put it, we don't want to "pay through the nose for immature technology." Why pay a huge markup for the best that's available right now, when the best that's available ten years from now is almost guaranteed to be a whole lot better—and possibly a whole lot cheaper to boot?