You can't just go to your local wholesale warehouse store and pick one up. That's because Marathon Water Heaters are only available through utilities like AEC. But that's not the only thing that makes them different. they're also one of the most durable, reliable and efficient water heaters on the market today. Manufactured by Rheem, the Marathon is designed to last and is constructed to provide maximum efficiency. Since water heating accounts for about 20% of the average residential energy bill, upgrading to the superior thermal storage provided by a Marathon will result in energy savings.