Vented or Ventless Chimney Damper

[Pirateghost]

I am thinking of yanking out the over-kill wood insert and going with ventless logs. I want to use ventless so I can use them to heat the bulk of the home when the power is out, not often.

When using the logs just for looks, I would prefer to vent the exhaust up the chimney.

Was looking at top mounted dampers and saw some notes that they are not allowed with gas. Is that for vented logs only?

Any problems venting ventless logs when the heat build up is not desired?

Thanks.