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What is the cost to run Rheem water heater for a month?

Rheem has been one of leading companies in hot water heating since their start in 1930's. They have products for both RESIDENTIAL as well as COMMERCIAL use. From instant hot water heaters (tankless water heaters) to storage hot water heaters, they have products that work with propane gas, electric water heaters, liquid propane water heaters and so on. On top of that, Rheem also provides with energy star rated products which save you energy bills as well. Getting an yearly cost on all water heaters provided by rheem would be very difficult. But the information below will give you an idea of how much a rheem water heater costs to run for a month.

Test #1 , between the traditional electric and gas tank water heaters, showed natural gas water heating operating costs to be 35% less than the electric water heating system operating costs. This was based on typical usage of an average four-person household.
Test #2 measured delivery (how much hot water can you get from the tank before you run out). The natural gas tank delivered 36% more hot water than the electric unit. That’s an extra 33.2 gallons of hot water for bathing, washing clothes and dishes.
Test #3 measured recovery (how much time does it take for the water heater to heat the incoming water to the desired temperature). The natural gas tank recovered 64% faster than the electric tank.

This values are based on an average usage and it does not reflect what each water heater would cost. This is just to get an idea of the cost of running a rheem water heater and it should be taken as the approximate or actual cost of running the water heater.

Summary of Results

Water Heating System


Monthly Operational Costs


Hot Water Delivery(gallons)


Recovery Time (min:sec)

Natural Gas Water Heater(Rheem Model21V40-38)




Electric Water Heater (Rheem Model 81V40D)