Todd said:
Yes, the EPA rates all non cats at 63%, but they also list cat stoves at 72%. Seems to me cats are a little more efficient according to their test. I know there are other test labs out there, but they are bias to the manufactures to make their numbers more attractive to the buyer. They are both sweet looking stoves and I'm sure either will do the job.
The EPA DOES NOT test efficiency. As you rightly noted, they do IMPLY cat technology is more efficient - from the best I can gather, this is based on OLD non-cat to cat model comparisons? Maybe someone else knows more? The generalization may actually still be true based on a survey of all EPA approved stoves, I have absolutely no idea, but the generalization does more harm than good - each stove needs to be evaluated on its own. Again, those default ratings are completely meaningless.
If someone has a link to actual lab tested efficiency ratings - I would be VERY interested in seeing the data. I don't know why the EPA doesn't do it themselves as I don't think it would be a huge amount of additional work for them as they are already testing every model in other ways. All I've found so far is a comment on the
chimneysweep site saying "The fact is, there is much laboratory evidence [showing not-cat technology can be as efficient or moreso than cat technology]. Woodstove efficiency testing reveals the exact amount of heat a given stove delivers for a given quantity of wood burned, and independent laboratory test results document that EPA approved non-catalytic woodstoves are just as fuel efficient as catalytics. This means catalytic stoves won't burn any less wood than non-cats to heat the same area."
But getting back to the ATTEMPT at an apples to apples comparison, I will redo it with extra large cat compared to large non-cat.
NOTE: The extra large cat model takes 25 inch logs, has an 8" flue, and is AT LEAST 70 lbs. heavier (134 lbs heavier based on the owners manual!) - so this is NOT really "apples to apples" when compared to the non-cat model which takes 22-24 inch logs, has a 6" flue, and is significantly lighter.
Dutchwest EXTRA Large Catalytic Model specs:
EPA Emissions Rating 1.3 (grams/hr)
Btu/h (Max.) 55000 Btu
Btu/hr Range EPA Test Method 10,500 to 27,700 Btu/hr
Burn Time (Max.) up to 12 hours
Heating Area (Max) 2400 sq. ft.
Weight 550 lbs. (but the
owners manual says its 634 lbs!)
Unit Depth 18 in.
Unit Height 33 in.
Unit Width 28 in.
Dutchwest Large NON-Cat specs:
EPA Emissions Rating 1.31 (grams/hr)
Btu/h (Max.) 55000 Btu
Btu/hr Range EPA Test Method 11,300 to 26,500 Btu/hr
Burn Time (Max.) up to 14 hours
Heating Area (Max) 2400 sq. ft.
[from
owners manual]
Weight 480 lbs.
Unit Depth 19 in.
Unit Height 32.5 in.
Unit Width 29.75 in.
So the non-cat large model has basically the same EPA emissions as the extra large catalytic model, a similar (slightly tighter) BTU/hr range on EPA test method, the same max BTU, the same recommended heating area, and a better max burn time by two hours. So the specs are about the same. Without further information you have to assume the efficiency ratings are almost identical considering the similar EPA emmissions and BTU specs. The non-cat might be slightly more efficient given the longer listed max burn time, or the cat might be slightly more efficient given the slightly higher max BTU/hr range on EPA test.
Bottom line - for very similar specs, if you go the catalytic route you have a substantially heavier stove with a catalytic converter that has to be replaced every few years (or performance will fall off a cliff) , a 3 year warrantee, and the requirement of an expensive 8 inch flue. Compare that to the non-cat which has a longer max burn time, no cat to replace, has a 6 inch flue, and a lifetime warrantee.