7.10 Comparing Hot Water Heaters
7.10 Comparing Hot Water HeatersLet’s use the Energy Guide to perform a life-cycle analysis to help choose a water heater. Different models of water heaters with roughly the same capacity can vary dramatically in the amount of energy they use.
Instructions: Look at the Energy Guides for these three different water heaters and answer the questions below.
The prices of the water heaters are not included on the Energy Guide labels, so I've listed them for you.
- Electric Water Heater (Tank) $549
- Natural Gas Water Heater (Tank) $689
- On Demand Electric Water Heater $459
Text description of each Energy Guide Label.
First EnergyGuide Label for a $549 46 gallon tank electric water heater:
U.S. Government Federal law prohibits removal of this label before consumer purchase
ENERGYGUIDE
WATER HEATER--ELECTRIC TANK SIZE (STORAGE CAPACITY): 46 GALLONS
A. O. SMITH CORPORATION MODEL(S) E6-50H45D 130
Estimated Yearly Energy Cost $494
Cost Range of Similar Models. $154 to $630
First Hour Rating (How much hot water you get in the first hour of use)
very small | low | medium (62 Gallons) | high
Your cost will depend on your utility rates and use.
Cost range based only on models fueled by ELECTRIC with a medium first hour rating (51-75 gallons).
Estimated energy cost based on a national average ELECTRIC cost of 0.1400 per kWH.
Estimated yearly energy use: 3,531 kWH.
ftc.gov/energy
Second EnergyGuide Label for a $689 48 gallon tank natural gas water heater:
U.S. Government Federal law prohibits removal of this label before consumer purchase.
ENERGYGUIDE
WATER HEATER--GAS NATURAL TANK SIZE (STORAGE CAPACITY): 48 GALLONS
A. O. SMITH CORPORATION MODEL(S) G6N-T5040NVR 400
Estimated Yearly Energy Cost $330
Cost Range of Similar Models. $227 to $336
First Hour Rating (How much hot water you get in the first hour of use)
very small | low | medium | high (81 Gallons)
- Your cost will depend on your utility rates and use.
- Cost range based only on models fueled by GAS NATURAL with a high first hour rating (+75 gallons).
- Estimated energy cost based on a national average GAS NATURAL cost of 1.2100 per THM.
- Estimated yearly energy use: 273 THM.
ftc.gov/energy
Third EnergyGuide Label for a $459 on demand electric water heater:
U.S. Government Federal law prohibits removal of this label before consumer purchase.
ENERGYGUIDE
Instantaneous Water Heater - ELECTRIC
A. O. Smith Corporation Model(s) R2VR-180E 100
Estimated Yearly Energy Cost $98
THE ESTIMATED ANNUAL ENERGY COST OF THIS MODEL WAS NOT AVAILABLE AT THE TIME THE RANGE WAS PUBLISHED.
Cost Range of Similar Models. $82 to $90
Maximum Gallons Per Minute of Hot Water (GPM Rating)
very small (1.6 GPM) | low | medium | high
- Your cost will depend on your utility rates and use.
- Cost range based only on models fueled by ELECTRIC with a very small GPM rating (0-1.6 GPM).
- Estimated energy cost based on a national average ELECTRIC cost of 0.1400 per kWH.
- Estimated yearly energy use: 703 kWH.
ftc.gov/energy
Quiz Yourself
After looking through the information on the three Energy Guide labels, see if you can answer the following questions.
Still trying to figure out the payback period between the two tank heaters? The price difference between the two models was $140, with the electric water heater being cheaper to buy, and your annual savings for operating the water heater were $164, with the gas water heater being cheaper to operate. So after one year, you got back $164 out of the $140 extra you spent on the superior model. It took you less than a year to pay back the extra money you spent on the more expensive model.
Obviously, over time, it pays to buy an energy-efficient water heater. It also helps the environment by not using as much energy and thereby not emitting as much CO2, NOx, SO2, CO and particulate matter into the environment.