No, my house is not heated with propane. The sealed sump pump has been vented to the outside of the house. The corner of the house where the sump pump resides is a walkout. This was done when the sump was sealed to help vent the pump and also take care of any radon. The sump pump is actually enclosed in a closet and you do not smell anything around the pump which leads me to believe the smell is not originating from the pump. Thanks for your comments. Any other suggestions?