The smaller Marathon units will cost approximately 2 to 3 times more than a basic steel water heater of the same size. That is not a real comparison though, as you are comparing a lifetime warranty product that is super insulated, against a 5 or 6-year warranty product with minimal insulation. Remember that the Marathon tank will not leak or rust; while your steel tank will eventually fail and you will be installing another tank soon....it's just a matter of time. The Installation process for the Marathon is no more and sometimes less than for steel units.
Larger units such as the 85 and 105-gallon models are typically the same cost or less than short-lived steel units of the same size. Our manufacturing process is technologically advanced and very efficient so our incremental cost between our smaller tanks and our larger ones is much smaller than that of steel tanks. We are currently offering a $200 rebate on Marathon the 50-gallon and 85-gallon water heaters for Columbia Rural Electric Association members, when installed at a location we serve.