Vent free fireplaces are designed to create almost 100% complete combustion. This essentially means that the exhaust is going to consist almost entirely of water vapor and carbon dioxide, not the dangerous gases such as carbon monoxide.
Nevertheless, the water vapor and carbon dioxide can be bothersome to those with respiratory issues such as asthma or sinus problems. To those with a keen sense of smell, the odor could also be a nuisance. In any event, we recommend installation of a carbon monoxide monitor in areas where a vent free appliance is used.
on December 24, 2012