Green Collar Careers - Water
About half of the water heaters in America are electric. That
tends to skew the numbers a bit from
Chart 202 as
the report was generated using all forms of water heating. In
effect homes with electric water heat, the proportion of electricity
used is doubled. Another way to put it is if the home has
electric water heat it will be closer to 18% of the power bill.
Typically natural gas will cost less then half of what electricity
costs to heat water. Propane cost is dependent on volatile oil prices
and may not offer any advantages. Solar water heating has the lowest
operating cost with the highest new system cost.
When a builder installs a water heater in a new home they will choose
the least expensive model unless the buyer has specified a particular
model. Most homeowners will wait until a water heater fails or worse
until they begin to leak before replacing them. Chances are the
homeowner will not be willing to upgrade the water heater but in case
they are the best option for electric is to select a tankless
Most homeowners never bother to adjust the water temperature on their
water heaters and builders will typically set the temperature to about
160°. Every 10° reduction will save about 4% energy cost on a tank
type water heater. The only thing in most households that needs water
to be above 120° is a dishwasher that unusually operates at about
135°. Most dishwashers have pre-heaters so 120° is really an ideal
setting. Resetting the water heater to 120° (usually about mid way on
the thermostat) can reduce power required by the water heater by 16%.
From chart 1 above we see that water heating accounts for an average
of 9% of the average total consumption, and recall that only half the
water heaters are electric.
For a home with electric water heat double the 9%. Multiply 18% *
16% for a net of about 3% savings on electricity.
Copper is a great
heat conductor and most homes are plumbed with copper. Be sure
the exposed hot water pipes are wrapped with an insulating jacket.
Its not a major savings but enough that an 8 foot jacket section will
pay for itself over just a few months.
Water Tank insulation
blankets are helpful but often take a year or more to pay for
Homes that have long runs from the hot water tank to the kitchen
sink may benefit from an under-sink tankless water heater. Every
second it takes to deliver hot water to a tap with a typical 2 gallon
per minute wastes about 6 Watt Hours of electricity. Say it
takes 60 seconds to get hot water and hot water is drawn 3 times a
(6Wh * 60 seconds * 3 times per day * 365 days per year) / 1000
= 394 kWh
At 12¢ a kWh, that costs $47 a year. An under-sink
mini tankless water heater system (plug in 110 VAC) runs about $200 so
the payback is about 5 years.
To learn more about reducing
electricity consumption with electric water heaters use the search
tool below to look up efficient water