http://www.ho****er.com/products/residential/gas.html-

The more hot water you need, the more you need a Vertex water heater.
Through an inspired blend of innovation, efficiency and years of
industry expertise, A. O. Smith has created a family of state-of-the-
art products that provide a long-lasting supply of hot water during
those times when everyone in your home needs it most. Vertex™ power-
vent and power direct-vent gas water heaters take high-demand homes to
the pinnacle of hot water availability. Vertex offers up to 96%
thermal efficiency with performance that rivals much larger water
heaters. With its fully-condensing design, Vertex delivers “continuous
hot water” — shower after shower, hour after hour. Yet it’s easy to
install, with dimensions and installation requirements comparable to
standard power-vent and power direct-vent units.

and ransley you claim having a tankless but now claim you have vertex
high BTU unit. which if either do you really have?