Choose catalytic if you want long, even burns at low output and don't mind operating a bypass damper and replacing the catalyst every several seasons. Choose non-catalytic for simpler operation and fewer parts to maintain; most stoves sold are this type.
Two routes to the same limit
Every new wood stove has to meet EPA's 2.0 grams-per-hour limit. EPA describes two general approaches. A non-catalytic stove creates conditions for complete combustion inside the firebox: insulation that keeps it hot, a large baffle that gives the gases a longer, hotter path, and pre-heated secondary air fed through small holes above the fuel. A catalytic stove routes the smoke through a ceramic or metal honeycomb coated with a catalyst, which lets the gases burn at a lower temperature than they otherwise would.
EPA notes that both approaches have proved effective but perform differently, and that most stoves on the market are non-catalytic while some of the more popular high-end stoves are catalytic.
How each one behaves day to day
| Catalytic | Non-catalytic | |
|---|---|---|
| How it burns smoke | Catalyst lets smoke burn at a lower temperature | Hot insulated firebox, baffle and secondary air |
| Extra control | Bypass damper, opened for starting and reloading | None beyond the air control |
| Burn style it suits | Long, steady, low-output burns | Livelier fires; output rises and falls with each load |
| Wearing parts | Catalyst degrades and must be replaced | Baffle and some internal parts need replacing over time |
| Sensitivity to fuel | Over-firing, trash and treated wood shorten catalyst life | Wet wood hurts performance as with any stove |
EPA says the catalyst can last more than six seasons if the stove is used properly, and that because catalytic stoves are slightly more complicated to operate, they suit people who like to get the most out of their equipment. Non-catalytic stoves ask less of the owner: load, set the air, close the door.
Which suits your heating pattern
If the stove is your main heat and burns all day through winter, a catalytic design's long, even burn at low output is its main advantage: fewer reloads at a gentle setting. If you light the stove in the evening and let it die out overnight, or you like to watch a lively fire, a non-catalytic stove fits better and leaves you one less component to look after.
Either way, fuel matters more than design. A catalytic stove fed wet wood will clog its catalyst and a non-catalytic stove fed wet wood will smoke; EPA's guidance to burn wood under 20 percent moisture applies to both.
Reading listings
Listings for catalytic stoves usually say so in the title or bullets and often state a longer burn time. Non-catalytic stoves rarely name their design; if a listing mentions secondary air tubes, a baffle and no catalyst or bypass damper, it is non-catalytic. Compare grams per hour and the maker's burn time when both are stated.
Catalytic stoves in our catalog: few catalytic models are sold through the retailers we track; most listings are non-catalytic designs..
Maintenance in practice
- Catalytic: open the bypass to start and reload, close it once the stove is hot, and plan for a replacement catalyst; check the manual for its operating temperature.
- Non-catalytic: inspect the baffle and secondary air tubes when you clean the stove, and replace warped or cracked parts with the maker's parts.
- Both: have the chimney inspected and cleaned each year before the season, as NFPA advises.