Ten Woodstoves Have Made The Grade

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Perhaps most significant, for the sake of experimental consistency the stoves were all tested with air-dried, dimensional Douglas fir lumber loaded at a density of about seven pounds per cubic foot of firebox. All of the stoves would have much longer burn times if they were loaded with densely packed hardwood. To use Woodcutter's huge Blaze King King as an example, if the firebox were only halfway filled with air-dried red oak firewood, the fuel load would weigh over 80 pounds, not the 29.2 pounds used in the tests. (Paul Tiegs hopes to offer more useful information to consumers by adding an optional third phase of testing for manufacturers—one that would examine heat outputs and burn times using loads of cordwood instead of lumber.)

For the moment, then, use the burn times and heat outputs that are listed only to make comparisons between stoves. If you're burning wood now, examine your present needs. Keep in mind that in some cases, designers have limited the minimum firing rate by putting a stop on the draft control to prevent the very dirty low burns . . . or limited air intake to avoid running into safety problems associated with overheating.

The final figures we've provided are Omni Environmental's figures for maximum and minimum draft one foot up the pipe from the stove. If you have problems with low chimney draft—back puffing and hard starting, for example—you're very likely to have more trouble with a high-efficiency stove. Because chimney draft is strongly influenced by flue-gas temperature, and because high heattransfer efficiency demands low flue-gas temperature, high-tech wood burners are inherently more troublesome when it comes to draft. There's no way to say what's enough draft without knowing the particular situation, but you can see that there are significant differences between the heaters. With the lower-draft models, you may find that you'll have to extend your chimney to provide adequate draw.

COME CLEAN

Woodstove efciency figures are inevitably likened to EPA fuel mileage ratings for cars. The lessons are much the same: Though these numbers are for comparison purposes only—your actual efficiency and emissions "may vary," as they say—we can just about guarantee that the performance of any of these stoves will be significantly better than that of the one you have now.

If you're burning four cords of $100-per-cord wood each year (and be realistic about what it costs—in time as well as expenses—even if you cut it yourself), stepping up from a 50% efcient black box to a 75% high-tech stove will save you 1-3/10 cords—or $130—in firewood alone in the first year. Add to that the cost (or aggravation) of chimney cleaning that you can save, and you've got a pretty convincing economic argument for buying a new stove. The health argument is even stronger: Using one of these stoves can be a "Clean Air Act" of your own.

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