[Mule98]

My son in law has an AO Smith heater in his basement with combustion air and exhaust ducted to the outside via a power vent. I have a heater that has exhaust ducted to outside but combustion air is drawn in thru the power vent from the basement air. Is one better than the other?

 

[roughneck]

Sealed combustion can cause less infiltration into the home as the mechanical area isn't being put under a negative pressure from the equipment.