Ventless will add a lot of moisture to the space.
I think you meant to say CO2 (carbon dioxide) not CO (carbon monoxide). Carbon monoxide is lethal and ventless heaters have several safety mechanisms built in to prevent CO production. Carbon dioxide is, indeed, produced by ventless heaters (along with water vapor). This can give you headaches if the concentration rises above about 4%.Un-vented heaters aren't magic, they still produce CO, they just dump it directly into the heated space along with all that moisture.
Most gas burners even when properly tuned make a little bit of co. It may not take much to cause health problems when the exposure is long enough.I think you meant to say CO2 (carbon dioxide) not CO (carbon monoxide). Carbon monoxide is lethal and ventless heaters have several safety mechanisms built in to prevent CO production. Carbon dioxide is, indeed, produced by ventless heaters (along with water vapor). This can give you headaches if the concentration rises above about 4%.
Ventless heaters aren't intended to be a primary (or continuous) heat source but they have their uses when installed and used as intended.
Maybe in a perfect world. And if you install a nice shiny new unit that has all those safety measures in place. There's millions of old units floating around that don't have any of that. Unfortunately most of them get installed and forgotten about anyway. Few will ever even get cleaned let alone properly serviced or tuned, especially in a garage setting.I think you meant to say CO2 (carbon dioxide) not CO (carbon monoxide). Carbon monoxide is lethal and ventless heaters have several safety mechanisms built in to prevent CO production. Carbon dioxide is, indeed, produced by ventless heaters (along with water vapor). This can give you headaches if the concentration rises above about 4%.
Ventless heaters aren't intended to be a primary (or continuous) heat source but they have their uses when installed and used as intended.
Back to the OP.
About your shop.
Is this a home owner / hobbyists shop or an area where you work 8 hours a day?
By now you have read all of the cautions and advice.
If you can crack a window open when using the ventless or you have enough air infiltration it will be fine. But regardless of your situation there will be moisture.
As you use the heater it will produce gasses. It also burns the air in your rooms which magnifies the problem. It is actually taking air away from your living space, shop space in your situation. High efficiency furnaces have a system that is a flue pipe and a fresh air pipe. That supplies air for the burner.
Have you mentioned how big your shop is? Insulated? Any other issues?