Q. Dear Umbra,

My husband and I just bought a house that has an older (at least 10 years old) hot-water boiler that uses oil. We were thinking of buying a new boiler and converting to natural gas because we thought it would be more efficient and a cleaner fuel source. However, we’re wondering if it would be just as efficient and “clean” to continue to use oil in a new very high-efficiency boiler. What are the pros and cons? Is heating oil really as bad as I think in terms of emissions?

Caroline L.
Arlington, Mass.

A. Dearest Caroline,

Congratulations! As you are discovering, one of the joys of home-moanership is endlessly mulling the pros and cons of various improvement options. I’m only too happy to add a bit more ambiguity to your life.

But first, for those scratching their heads and saying “a hot-water what?” (aka those who live in newer homes or homes not located in the North), a quick primer. A hot-water boiler is the key component of a forced hot-water heating system. This system also has a fancy name, hydronic. The boiler is a friendly, basement-dwelling machine that heats water and pumps it into radiators or baseboard heaters or sometimes tootsie-warming radiant floors. Anyone who has lived with such a system knows it is brilliant but often delicate, requiring adjustments and kind words to prevent clanging, banging, freezing, leaking, and other side effects. Not to frighten you, Caroline; I’m sure your system will behave just fine.

Can you cause it to behave even better? I never did get that pesky plumber’s license, so after you absorb my wisdom please do consult an actual professional or two.

First of all, it’s possible that your boiler has a few good years left in it. The Energy Star program recommends replacing a boiler if it’s more than 15 years old, an advanced age yours might not yet have reached. It’s also possible to retrofit a boiler, say our friends at the Department of Energy. It might be worth investigating this option further, if only for the chance to read about “modulating aquastats” (as it happens, an excellent potential band name).

Whether now or in a couple of years, an upgrade does seem to be in the cards for you. But DOE and your old friend Umbra recommend improving your home’s energy efficiency first — as we know, insulationness is next to godliness — which could mean you end up needing a smaller boiler. Savings all around!

As for fuel, it appears from my research that people do tend to be more satisfied with gas than oil. For one thing, it’s less expensive. (Oil prices have come down a lot lately, but not enough: the U.S. Energy Information Administration estimates average heating costs this winter of $578 for natural gas versus $1,392 for oil.) Gas boilers also require less maintenance, another cost savings. And your general hunch that oil is no friend to the atmosphere is correct. One study I consulted said oil not only emits higher levels of carbon dioxide than natural gas, it also emits 130 times more particulate matter — think soot, smoke, and the like. Yuck.

But natural gas, as Grandmother Fisk used to say, ain’t no picnic. Sure, it might be cleaner-burning than oil, but guess where much of our natural gas comes from these days? Fracking, which has been linked to groundwater contamination, earthquake activity, and the release of methane, a greenhouse gas far more potent than carbon dioxide.

I started to get excited thinking about how you could really go wild and install a geothermal or solar heating system, but I’m not sure that’s so practical in the Northeast. (Dearest readers in other regions should seriously consider this investment. We have got to kick this fossil-fuel habit.) You could see if any local oil company offers a biodiesel blend for your boiler, which would burn slightly cleaner but brings its own environmental issues. How about profligate use of down comforters? Slankets? Is moving to Hawaii in the cards? I suppose not, what with the recent home purchase and all.

Though it pains me to say it, I think natural gas does have the edge over oil, if those are the only two reasonable choices in your current situation. If you haven’t expended your what-should-we-do-about-the-boiler energy, I encourage you to read this super-helpful advice from the DOE. Spend the next few months insulating your attic, sealing drafts, and taking other measures to use less energy. And if you do upgrade, be sure to check into potential rebates.

Whatever happens, let’s hope the winter there in Arlington doesn’t hold a candle to last year. I hear that was wicked brutal.

Chilly,
Umbra