Efficiency vs emissions? i'm confused

[garybeck]

i'm shopping for a used wood stove and looking at specs a lot

how can a stove have very high efficiency (80+%), but poor emissions (>3gr/hr)
then i see other stoves that have lower efficiency (78%) but much better emissions (<1gr/hr)

i would think that efficiency and emissions are directly related... ?

 

[Highbeam]

Nope. Not directly related. You’ll need to look for one of the stoves that does well in both of those independent ratings. Then , consider cost, aesthetics, durability, clearances, etc.

 

[billb3]

i'm shopping for a used wood stove and looking at specs a lot

how can a stove have very high efficiency (80+%), but poor emissions (>3gr/hr)
then i see other stoves that have lower efficiency (78%) but much better emissions (<1gr/hr)

i would think that efficiency and emissions are directly related... ?

Kinda obvious they're not, no ?
Are you even comparing identical technologies ? Tubes/catalysts/hybrids ?
Or even identical testing methodologies ?

 

[bholler]

Kinda obvious they're not, no ?
Are you even comparing identical technologies ? Tubes/catalysts/hybrids ?
Or even identical testing methodologies ?

No need to compare identical tech. Just the same testing which we now have finally

 

[Highbeam]

No need to compare identical tech. Just the same testing which we now have finally

We were told by one manufacturer with actual experience in the epa certification process that the testing process is entirely different for cribwood vs. cordwood so you need to pay attention that you’re only comparing earned epa ratings from stoves tested using the same fuel type. I think this is bogus and that the epa should only allow one or the other so that test results are comparable.

Also, the test methods fir the 2020 certifications are not the same as previous test methods so I can’t compare my pre2020 ratings to 2020 ratings.

but heck, I do think we’re on the right path.

 

[bholler]

We were told by one manufacturer with actual experience in the epa certification process that the testing process is entirely different for cribwood vs. cordwood so you need to pay attention that you’re only comparing earned epa ratings from stoves tested using the same fuel type. I think this is bogus and that the epa should only allow one or the other so that test results are comparable.

Also, the test methods fir the 2020 certifications are not the same as previous test methods so I can’t compare my pre2020 ratings to 2020 ratings.

but heck, I do think we’re on the right path.

Yes 2020 standards are finally getting more standardized

 

[spudman99]

Emissions are the particulate matter that is measured at the flue.
Efficiency is the amount of heat emitted from the front.

Depending on the scrubbing technology the emissions can be higher with equal heat.