| There are a lot of tankless water heater | | | | 3.Daily power needed to heat the water to 110F is: |
| manufactures claiming a wide range of savings on | | | | 1.5 hours x 6.2 kW = 9.3 kWh |
| your next water heating bill. A quick search on the | | | | 4.Annual costs to heat water using a tankless water |
| web will show you a percent reduction of up 80%. | | | | heater is: 9.5 kWh/ day x 335 days/ year x $0.11 |
| However the question still exists: how much would | | | | kWh = $343 |
| you really save on your water heating bill using a | | | | 5.Average annual idle cost for a tankless water |
| tankless water heater? | | | | heater: $17 |
| Most importantly what is the payback or ROI of the | | | | So the total cost of heating water using a tankless |
| average tankless water heater and how does it | | | | water heater is $343 + $17 or $360. |
| compare to a traditional tank hot water system? Let | | | | What do these numbers mean? |
| us try to answer these questions. | | | | 1.The percent annual savings using a tankless water |
| Annual costs associated with water heaters of any | | | | heater over a traditional tank system is 50% or $375 |
| type are divided into 3 categories: | | | | C |
| 1.Energy costs to heat the water from its incoming | | | | 2.This amount ($375) is equal to the cost of an |
| temperature to the desired temperature. | | | | average mid-size tankless water heater. Please note: |
| 2.Standby energy costs: in the case of traditional | | | | Installation costs were found to be comparable for |
| tank heaters, standby cost is the cost of the energy | | | | both tank and tankless systems, ~$150. |
| to keep the water hot in the tank all day. For a | | | | 3.In addition there is the potential for tax credits for |
| tankless water heater standby cost is the cost of | | | | any tankless water heater. (Please visit for more |
| energy when the tankless water heater is running idle | | | | information ) |
| (minimal). | | | | 4.Given the longer life of a tankless water heater at |
| 3.Installation costs: This is the cost to install the | | | | 22 years versus a tank system 10 years there is the |
| heater and all its piping system | | | | potential of saving over $4,000 over the long term. |
| So let us examine these costs for both traditional | | | | Notes: |
| tank heaters and tankless water heaters in detail. | | | | 1.The incoming water temperature from which the |
| Average Annual Traditional Tank Heater Costs | | | | department of energy (DOE) calculations are made, |
| 1.Annual hot water demand: 87 gallons / day x 335 | | | | has been established at 57F. In many parts of the |
| days / year = 29,145 gallons/ year. | | | | U.S. one does not normally experience inlet |
| 2.Power to heat up 1 gallon of water from 57 oF to | | | | temperatures this cost year round however, we |
| 110 oF according to the multi-housing laundry | | | | used 57F as our inlet temperature. 110 oF is the |
| association is 0.2 kWh | | | | average household hot water operating temperature. |
| 3.The annual power requirement of heating the water | | | | This translates to 53 degrees of temperature rise for |
| from 57 oF to 110 oF for an American household is: | | | | both tank and tankless water heating systems |
| 29,145 gallons/ year x 0.2 kWh/ gallon = 5,900 kWh/ | | | | 2.According to the U.S. department of energy (July |
| year | | | | 2006) the average American household consumes 87 |
| 4.The cost of 5,900 kWh: 5,900 kWh/ year x $0.11/ | | | | gallons of hot water per day |
| kWh = $649/ year | | | | 3.Average cost of electricity for the United States at |
| 5.The cost to keep one gallon of water hot is $0.003 | | | | the time of writing, is $0.11 kWh, as per the DOE. |
| So, the cost to keep 21,145 gallons of water hot | | | | Disclaimer: The information on the system, product or |
| (standby): 21,945 gallons/ year x $0.003/ gallon = $87 | | | | material presented herein is provided for informational |
| So the total annual cost of heating water using a | | | | purposes only. Please ensure that you consult a |
| traditional tank system is $649 + $85 or $736. | | | | qualified technician prior to installing a tankless water |
| Average annual tankless water heater costs | | | | heater or any suggestions put forward by e-Smart |
| 1.Average energy to heat water to 110 oF is 6.2 kW | | | | Living. |
| 2.Average daily usage is 1.5 hours | | | | |