High efficiency systems run a lot different. The exhaust doesn’t get even remotely hot enough to melt them. Similar, there are gas fired water heaters that exhaust through PVC as well. Newer houses don’t even have a metal B-vents/chimneys anymore since everything just vents out the side of the house on their own.
I have a tankless which is supposed to be super efficient but I don’t remember what it’s exhaust piping is. I know the stuff coming out of the house is plastic as well, but I don’t recall what the piping coming out of the unit is.
High efficiency systems run a lot different. The exhaust doesn’t get even remotely hot enough to melt them. Similar, there are gas fired water heaters that exhaust through PVC as well. Newer houses don’t even have a metal B-vents/chimneys anymore since everything just vents out the side of the house on their own.
I have a tankless which is supposed to be super efficient but I don’t remember what it’s exhaust piping is. I know the stuff coming out of the house is plastic as well, but I don’t recall what the piping coming out of the unit is.