Case Study – Lake Hope State Park, Vinton County, Ohio

By Jens Bolleyer


Lake Hope State Park a natural paradise lies within 26,000-acres of the Zaleski State Forest in Southeast Ohio.  Lake Hope has 69 cottages that are rented out year round with most rentals occurring in the spring, summer, and fall.


Lake Hope State Park conducted in-house guest surveys in which guests stated that they run out of hot water frequently. Darryl Trigg, Park Engineer, contributed to this case study in conjunction with Southeastern Ohio Power for Rod Garey, Park Manager, Lake Hope State Park.  In order to obtain accurate information, Lake Hope installed water and electric meters in each cabin to monitor hot water consumption. They were able to obtain accurate measurements of the number of kilowatts needed to heat a gallon of water with a storage tank water heater vs. an Eemax Electric Tankless Water Heater.


At Lake Hope State Park a test was conducted comparing two cottages – one with a conventional tank water heater and one with an Eemax EX190TC Series Two Electric Tankless Water Heater.  Here are the results:

Lake Hope has 69 cottages. Each one is rented an average of 182 nights per year, which means for all 69 cabins, the average occupancy is 12,558 nights rented per year.  Multiply that by 25 which is the average amount of gallons of hot water used per cabin per night, and you have the total number of gallons used in one year.

Here is a breakdown of calculations:

12,558 x 25 = 313,950 gallons of hot water per year
313,950 x .032 = $10,046.40 (cost per year with a conventional tank-style water heater)
313,950 x .023 = $7,220.85 (cost per year with an Electric Tankless Water Heater)

$10,046.40 (cost per year for Tank system)
– $7,220.85 (cost per year for tankless system)



Electric Tankless Water Heaters use energy only when water is being drawn from the hot water tap at the fixture.  Conventional storage tank type heaters keep large amounts of water constantly heated to a high temperature of 140ºF, waiting for possible use, as a result tank water heaters are subject to “stand-by-heat-loss”.  They are also prone to leak and require by code a temperature and pressure relief valve, drain pan and thermal expansion tank which by code are not required for tankless heaters.


•    Hot water arrives instantly with point-of-use installation. No wasted water down the drain.
•    No stand-by heat loss since there’s no large storage tank to keep heated 24/7.
•    Up to 90% space saving compared to large tank heaters.
•    Continuous hot water flow, guests never run out of hot water.
•    No heating of water when cabins are not occupied means lower utility cost.
•    When cabins are occupied, rental fees pay for water use.
•    Easy maintenance and reduced downtime  improves customer service, with  no tank to drain before changing elements.
•    Saving energy means you are reducing your carbon footprint which is good for our planet.


Space-saving tankless heaters allow Lake Hope to keep water hot when and if their guests need it. They are saving nearly $3,000 a year with their new Tankless system from Eemax. This study proves that on-demand tankless water heating is one of the most effective ways to conserve energy, water, space, and money.

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