White Mountain Hearth Logs

It is Empire's hearth product brand, so a White Mountain Hearth log set is an Empire product. If you have been comparing the two names, they are the same manufacturer rather than competitors.

Where the exhaust goes, and it decides which fireplace the set can go into. A vent free set burns cleanly enough to need no flue and puts its heat into the room. A vented set needs a working chimney with the damper open, and gives you a taller, more realistic flame in exchange for most of the heat going up the flue.

No, and this is the question worth getting right. The set has to match the firebox it is going into: vent free sets need a firebox rated for them, vented sets need a working flue. A sealed direct vent fireplace takes neither, because it is a closed appliance.

Not everywhere. Vent free gas appliances are prohibited or restricted in some states and cities, California and parts of Massachusetts among them, and some codes bar them from bedrooms. Check local code before ordering.

Only the ones listed for outdoor use, which are built in stainless steel for weather exposure. An indoor set moved outside will corrode. Check the listing on the specific product rather than assuming from the photograph.

Up to 50,000 BTU on the outdoor stainless set. On a vent free set most of that heat stays in the room; on a vented set most of it goes up the chimney, which is the trade you make for the better flame.