Waterheatertimer.org
is a self-help site

2012

All Costs are energy, so total energy-cost equals purchase-price of water heater, plus installation, plus expected maintenance, repairs-and-parts, plus water softener-and-filter, plus disposal-recycling cost, divided by years of tank life. These numbers are added to monthly energy consumption to measure true cost of a water heater.

Industry efficiency numbers consider only energy cost per gallon of heated water for brand new tank under ideal conditions. And do not consider drop in efficiency over time, or costs listed above.

How much does it cost to run electric water heater

3 hours is approximate daily run-time for water heater [depending on usage and temperature of incoming water etc]
Bath uses 12-15 Gallons hot water <> shower uses 5-9 Gallons hot water > Hot water use chart

Example
5500 Watts x 3 hours = 16,500 watt-hours or 16.5 Kwh per day
For a full 30-day month <=> 30 days x 16.5 Kwh per day = 495 Kwh per month for water heater electricity
Calculate cost <=> 495 Kwh x $.10 per Kwh = $49.50 + add tax

3 hours per day

5500 Watt = 495 Kwh per month
4500 Watt = 405 Kwh per month
3500 Watt = 315 Kwh per month
1500 Watt = 135 Kwh per month
Watts appear on water heater label

3 hours a day @ 10¢ per Kwh
5500 Watt tank = $49.50 per month
4500 Watt tank = $40.50 per month
3500 Watt tank = $31.50 per month
1500 Watt tank = $13.50 per month
+ add tax

3 hours a day @ 12¢ per Kwh
5500 Watt tank = $59.40 per month
4500 Watt tank = $48.60 per month
3500 Watt tank = $37.80 per month
1500 Watt tank = $16.20 per month

3 hours a day @ 14¢ per Kwh
5500 Watt tank = $69.30 per month
4500 Watt tank = $56.70 per month
3500 Watt tank = $44.10 per month
1500 Watt tank = $18.90 per month

3 hours a day @ $.16 per Kwh
5500 Watt tank = $79.20 per month + tax
4500 Watt tank = $64.80 per month
3500 Watt tank = $50.40 per month
1500 Watt tank = $21.60 per month

3 hours a day @ $.20 per Kwh
5500 Watt tank = $99.00 per month + tax
4500 Watt tank = $81.00 per month
3500 Watt tank = $63.00 per month
1500 Watt tank = $27.00 per month

Average electric price by state

Avg state price chart in pdf

Electric water heater and energy factor
EF Energy factor	Gallons	Typical yearly cost	EF or energy factor for electric water heater is higher than gas water heater since element is immersed in water and full heating goes into water. No waste goes up flue stack as in gas water heater. However gas delivers more BTUs faster than electic.
.95	40-50	$492
.93	40-50	$503
.90	40-50	$520
.88	60	$531

How to install electric meter on 240Volt water heater
Forget the guesswork. Put a meter on it.

Two methods:
1) Install electric meter on line going to water heater
2) Install Hour meter on each water heater element

Family Chart for setting water heater timer

Tank wattage:
Figure volts amps watts for water heater
1. Find label on side of water heater
2. -or- Google brand and model number of heater to find .pdf of manual
3. Voltage & wattage also written on end of each element see example

See label image

Look for watts on label
1. Watt rating of element(s) is usually 1500, 3500, 4500, or 5500 Watts
2. Element wattage ranges from 600 to 6000
3. Water heater wattage is same as element wattage, since both elements are not turned ON at same time.

Larger image

Read: Heat pump connected to refrigerator heat

Cost performance of electric water heaters.
Numbers are for comparison only. Maintenance is not considered.
Cheaper water heaters have lower EF, are cheaper to maintain.
More expensive water heaters generally have higher EF, are more expensive to maintain. You probably cannot fix heat-pump water heater yourself.
All costs are energy and more expensive heaters cost more to install and cost more to maintain, so the payback period shown is probably not accurate.

Read PDF
Attend the Hot Water Forum
9 ways to save with water heater

How much does it cost to run GAS water heater

See pdf with more details

AO Smith gas
Larger image

Size 40-50 gallon

Energy factor

Natural Gas year 2010

LP Gas

.56

$315-320

$530

Typical gas: .58 to .62

.60

$300-315

$500

.67

$272-280

$475

.82

$225

$380

Water heaters with higher recovery and first-hour delivery may not have EF rating.
High-recovery heaters are for high-demand, and consume more BTU per gallon of hot water to keep up with demand.
Tankless water heaters also consume more BTUs per gallon of hot water since water is heated quickly as it passes in a pipe. High consumption heaters have larger gas lines and vent pipes.

Numbers apply to new water heaters

EF energy efficiency factor explained
First hour rating explained

Larger image

Cost performance of gas water heaters.
Numbers are for comparison only. Maintenance is not considered.
Cheaper water heaters have lower EF, cheaper to maintain.
More expensive water heaters generally have higher EF.
Payback period is very large, and exceeds likely lifespan of each product.
All costs are energy and more expensive heaters cost more to maintain.

I question that tankless payback is correct since tankless manufacturers market themselves as 'endless' hot water, implying more gallons of usage. Moreover tankless numbers are based on factory temperature setting 120 degrees F, which could be lower than most people set temperature.

Read PDF
Attend the Hot Water Forum
How to install typical gas water heater

Example Energy Factor Charts for gas water heater Energy factor between gas and electric cannot be compared Each company makes many different models of water heater Each model has chart showing specs including tank size, model number, recovery, BTU input, Energy Factor, etc Water heater manufacturers
	EXAMPLE typical gas water heater EF American energy factor .58 to .62 Larger image
	EXAMPLE typical gas water heater EF AO Smith energy factor .58 to .62 Larger image
	EXAMPLE typical gas water heater EF Rheem energy factor .58 to .62 Larger image
	EXAMPLE 2010 chart showing typical Lowes Whirlpool water heaters EF .58 to .62 Larger image

Compare equipment using EnergyGuide Label. Label shows what it costs to operate each unit on an annual basis, using national average energy prices. EnergyGuide shows how a particular model compares with other similar models. Be sure to compare water heater models with the same first-hour recovery rating when using the EnergyGuides. Higher first-hour deliver, and higher recovery models will cost more to operate per year since they consume more fuel per minute of operation. All figures are approximate*
Figure annual expense using local costs of energy. Residential gas prices are usually calculated in units called therms. (A therm is equal to 100,000 Btu.) (100 cu feet gas = 100,000 Btu) Locate per/therm cost on gas bill, or call gas company. Use chart below to estimate yearly energy costs.
Larger image All figures are approximate.	Use chart to compare gas water heaters at time of purchase Call gas supplier to get therm value of your gas If your gas bill shows 60 cents per therm, then look at water heater energy factor to estimate yearly cost. For example: Cost per therm of gas is 60 cents. Difference between EF.51 and EF.63 is $33 per year Life of appliance is 10 years = $330 over 10 years Be careful to compare water heaters with same recovery and first hour delivery. Higher recovery and first-hour water heaters consume more fuel and cost more per year to operate. 13.446 lbs CO2 per therm
All figures are approximate* Figures are for NEW water heater set at 120 degrees Figures are for optimal conditions: Burner is clean, combustion transfer surface is not covered with sediment, etc Temperature setting affects cost: higher thermostat setting costs more Incoming water temperature affects cost: colder water costs more to heat All costs are energy: Lower consumption and turn down thermostat to save money. Maintain water heater so water heater is not replaced frequently. Read more Gas water heater efficiency with water softener Read Efficiency is not same as energy savings/ all costs are energy.
1 gallon water = 8.34 lbs. / It takes 1 BTU to raise 1 lb of water 1° F so it takes 8.34 BTUs to raise 1 lb of water 1° F