what does the installation manual say ....it should give you that answer...ben srI am installing a Rinnai RL75iN Natural Gas Tankless Water Heater and have a question about the ventilation installation. I live in Illinois and am curious how high above the ground level I need the direct vent termination to be on the outside wall? It appears that 12" may be the answer but I'm concerned about meeting code where snow may change the requirements. Any definitive answers here? Thanks in advance!