Question: Hi- we are considering installing a fireplace insert (either wood or pellet-burning). We are concerned about exposing our 3 parrots to toxic gases such as carbon monoxide and other nasty things. Birds are very sensitive to low levels of these gases, and we are wondering if these stoves would harm them? Also- of the 2 types of inserts, which one would burn cleaner? Answer: Neither unit, with proper installation and use, will produce CO in any measurable quantity INSIDE THE HOME. When a wood or pellet stove is correctly installed, the chimney will serve as the venting for all the products of combustion. CO is more of a potential with Coal or even gas, both of which can produce the gas without a tell-tale smell. With wood or pellets, you'd smell smoke long before there was a CO problem.