What is cat/non-cat?

"Cat" here means "catalytic converter," a device that causes a chemical reaction to proceed at much lower temperature than in its absence.

Practically, it's a ceramic or metallic honeycomb with a trace of palladium or platinum on the surface, that can be placed in the exhaust path from the main firebox, such that secondary air and smoke can be gotten to burn at much lower temp than otherwise. This especially comes into play for low-rate burn. Cat can be bypassed for startup and high-rate burn.

For EPA-compliant non-cat stoves, the engineering goes into pre-heating and flow-control of secondary air, so that what would otherwise be smoke and creosote deposits is burnt.

In either case, efficiency is boosted, and carcinogen release is greatly reduced.

Some reading for you:
http://www.woodheat.org/index.php?option=com_content&view=article&id=8&Itemid=29

Paint kills one but not the other.

Glad you like your stove!

New wood stoves must meet EPA requirements for the maximum amount of particulates they can put out. Pollutants are reduced by burning them, and there are two ways to burn them. One is to have a catalytic burner like somebody described above. The exhaust air is routed through the 'cat' and smoke and flammable gases are burned inside the cat. The cat allows the burn to ignite at a lower temperature than without a cat, so the stove can keep burning pollutants and producing heat from the burn despite a smoky or smouldering 'primary' fire in the firebox. The other system, usually called 'non-cat' stoves, is to insulate the firebox and introduce hot fresh air at the top of the firebox. The insulation raises the temperature, so when smoke and gases rise from the burning wood they can ignite with the secondary air. The secondary air usually comes from perforated tubes at the top of the firebox, which in most stoves are plainly visible, and secondary flames are also plainly visible in the firebox with non-cat stoves.

Franks said:

Paint kills one but not the other.

Glad you like your stove!

Click to expand...

You know.. I see this on here from time to time, and while I in no way mean to put anyone down about the statement, the best cat I ever knew walked through some "Kilz" primer, and it then licked it's paws clean before we knew.. it died. :-S

I was really upset for a long time, because before that cat (and marriage to it's owner) I never cared one way or another about cats. Never had another as neat as that one. We don't have one now, after about 6 of them after him, I lost the desire to put up with them full time if I couldn't find one like him..