I have a power vented water heater. The PVC exhaust pipe runs up in to the ceiling then horizontally outside my house. This was installed by professionals, not DIY. The outlet at the back is perpendicular to the wall - in other words the "mouth" of the PVC pipe open directly to the wind. If I stand in my utility room and place my hand over the back of the power vent intake when the unit isn't running, I can feel a decent cold draft. The floor above where this exhaust piping goes is very cold too.
Am I right to suspect that the installers should have added an elbow and made the mouth of the exhaust pipe "point down"?
Would a further step be add some sort of device on the end to only open when there's exhaust pressure?