Eco, or no?

If you’re craving a good, long soak in a hot tub but don’t want the guilt from using an energy-sucking machine, look into a manufacturer called Snorkel.

The Seattle-based stove company makes red-cedar spas heated by an underwater stove. This may sound kind of odd, but the wood-burning insert works just like a fireplace: wad up paper, add kindling and wood, then light it up.

Snorkel’s Web site (www.snorkel.com) says virtually any wood can be used, including branches and lumber scraps. The site mentions that even coal can be used, but Tom Slater, the company’s president, says that reference simply illustrates the range of fuels the stoves can handle—“we don’t suggest or recommend that people use it.”

Particulate matter is of particular concern in the North State, and wood stoves have come under scrutiny. “To the extent that is a critical issue in your area, it wouldn’t be advisable to use them,” Slater replied by e-mail. “In general, they are probably best suited for less dense areas such as outlying suburban to semi-rural”—provided they’re not “certain mountain valleys where air can get trapped.”

On the plus side, Slater wrote, “our stoves are typically operated at a hotter, high rate of burn to heat the tub up as quickly as possible. A fire that is burning hotter usually burns cleaner than a slower-burning fire.” Plus, people use hot tubs less frequently and for less time than room-heating wood stoves.