watt density

Why? 3 reasons:
1) 'Alterations' that exceed operating parameters of the heater are not covered by any warranty, such as installing commercial 180°F thermostats instead of the residential 150-160°F thermostats, or rewiring ordinary non-simultaneous residential tank for simultaneous operation. How to wire thermostats
2) Safe electric practice requires 30 amp breaker and 10 gauge wire to supply power for ordinary 240 volt 4500 watt non-simultaneous residential water heater ... 10 gauge wire has safe maximum of 80% of rated value or 24 amps.... but manufactures install the smaller 12 gauge wire for internal wiring from top of tank to upper and lower thermostats and elements ... 12 gauge wire is rated maximum 20 amps, with safe maximum of 80% or 16 amps. The higher wattage 5000-6000 watt elements draw 20-23 amps, so the manufacturer-installed 12 gauge wires inside tank will run hotter, and possibly melt. Figure volts amps and watts for water heater
3) 5000 and 6000 watt elements will reheat water inside tank faster than 4500 watt ... the added power will cause more moisture, more expansion and contraction of steel tank, and shorten life of product.

Watt rating of element divided by square inch of surface = watt density -The difference between 4500 watt high density and 4500 watt low density element is the length and surface area of element. Applies to single-phase residential and commercial 3-phase water heaters. Read about 3-phase water heaters The longer the element length, the more square inches of heating surface, and the lower the density. The 'foldback' element has more length than straight element, so the foldback element yields lower watt density. Foldback design is to keep element short enough to fit inside tank diameter. Performance-wise: -4500w high density and 4500w low density take the same amount of time and energy consumption to heat water. Why? Because the power output of element (measured in wattage or kilowatt or Kw) is same with both elements. Assumes other factors ... such as thermostat setting, incoming cold water temperatures, tank condition, scale build-up on elements etc ... are same. Resource: read about recovery Longer life for low density -Lower watt density elements can last longer in some conditions of hard or heavily mineralized water. Why? Because low watt density element has same heating potential as high density, except spread across more surface area. "The watt-density of an element is basically the amount of heat concentrated on any point on the surface of the element." So each square centimeter of lower density element is slightly cooler, and less reactive with water. Resource: see hard water map Higher temperature settings on water heater (especially above 140°F) will cause more particulate and scale etc to percolate out of the water. Higher temperatures can yield increased first hour delivery (more hot water from one continuous draw), but also causes risks ... scalds from hot water, more moisture to rust tank, more expansion-contraction of tank resulting in shorter tank life, more pressure inside tank that increases strain on tank and plumbing pipes, shorter life of elements, thermostats, greater standby loss, higher power consumption, etc.
If elements burn out frequently .... If elements burn out frequently, then install low density element if area has hard water see map ... and/or .... reduce element wattage from 4500 watts to 3500 watt ... or 2500 watt. Lower wattage element will still heat tank fully ... but more slowly ... so lower wattage elements reduce the amount of usable hot water from a single continuous draw (first hour delivery is less), and cause delay in reheating tank (recovery takes longer). Read about recovery You can also lower thermostat setting to 110-115°F so less particulate distills out of water, and elements run less frequently and last longer. This likewise reduces first hour delivery. Simply installing low density element with same wattage as original will not change performance of heater ... so first hour delivery and recovery are same as original. Resource: How to clean sediment out of electric water heater All water heater manufacturers install high density elements because they are cheapest Customer can replace factory elements on a 240 volt 4500 watt water heater with low density 4500 and 3500 watt elements. Product warranty will not be voided ... unless higher wattage element is installed. So typical 4500 watt tank warranty will cover 4500 watt and 3500 watt replacement, but not cover tank if 5000-6000 watt elements are installed. Why? 3 reasons: 1) 'Alterations' that exceed operating parameters of the heater are not covered by any warranty, such as installing commercial 180°F thermostats instead of the residential 150-160°F thermostats, or rewiring ordinary non-simultaneous residential tank for simultaneous operation. How to wire thermostats 2) Safe electric practice requires 30 amp breaker and 10 gauge wire to supply power for ordinary 240 volt 4500 watt non-simultaneous residential water heater ... 10 gauge wire has safe maximum of 80% of rated value or 24 amps.... but manufactures install the smaller 12 gauge wire for internal wiring from top of tank to upper and lower thermostats and elements ... 12 gauge wire is rated maximum 20 amps, with safe maximum of 80% or 16 amps. The higher wattage 5000-6000 watt elements draw 20-23 amps, so the manufacturer-installed 12 gauge wires inside tank will run hotter, and possibly melt. Figure volts amps and watts for water heater 3) 5000 and 6000 watt elements will reheat water inside tank faster than 4500 watt ... the added power will cause more moisture, more expansion and contraction of steel tank, and shorten life of product. Voltage must match The voltage on new element, no matter if low density or high density, must match incoming voltage. So if water heater is connected to 240 volt, then new low density element must be 240 volt to avoid element burning out. If 120 volt element is connected to 240 volt, then element will burn out immediately when power is applied. Resources: How to replace elements How to increase amount of hot water
$25 - $47 5 year warranty Ultra Low Watt Density/ ripple Hard water element Resists high mineral count Minimum 15" diameter tank Buy 240 volt: 4500 watt 4500 watt 13" diameter 5500 watt Ripple elements Camco elements Lifetime warranty 4500 watt +limited lifetime element Reliance / no extended warranty Low density/ ripple Min 13" tank Buy 240 Volt Reliance 5500 watt ripple Reliance elements	$13 - $26 5 year warranty Ultra Low Watt Density/ foldback Hard water element Resists high mineral count Check minimum tank diameter Fits any tank above minimum dia Buy 120 volt 1500 watt 120 volt 8" minimum Buy 240 volt: 2500 watt 3500 watt 4500 watt / best value 5500 watt Warranties do not cover dry fire (electricity ON before tank is full of water). Resource: Read about dry fire/ pdf page 2	$10 - $16 Camco/ no extended warranty Low Watt Density/ foldback Check minimum tank diameter Fits any tank above minimum dia Buy 240 volt: 2500 watt 3500 watt 4500 watt 4500 watt 12 pack 5500 watt for faster heating 6000 watt / 17" minimum tank (6000 watts requires 8 gauge wire) Elements on this webpage are rated for AC voltages. AC elements with work with DC But Thermostats will melt with DC

$20 - $30 per element Camco/ 5 year warranty/ bolt-in Low density foldback Hard water element Resists high mineral count Buy 240 Volt 4500 watt 240 volt 5500 watt 240 volt Warranties do not cover dry fire (electricity ON before tank full of water). Resource: Read about dry fire/ pdf page	$15 - $20 per element Camco/ no extended warranty Foldback Minimum Tank diameter varies Buy 240 Volt universal flange 4500 watt 12 pack 4500 watt 240 volt minimum 9" diameter Buy 240 Volt flat flange 4500 watt 240 volt 13" tank	$10 - $20 per element Camco/ no extended warranty High density Minimum Tank diameter varies Buy 120 Volt 6-9" diameter tank 1500 watt 120 volt 9" tank 2000 watt 120 volt 9" tank Buy 240 Volt 1500 watt 240 volt 8" tank 2500 watt 240 volt 10" tank 3000 watt 240 volt 12" tank 3000 watt flat flange 14" tank 3500 watt 240 volt 14" tank 4500 watt 240 volt minimum 13' tank 4500 watt 240 volt 15" tank
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When replacing elements: 1) Look for label located on side of tank. Label will show volts and watts for upper element & lower element & total connected watts (which is max wattage consumption of appliance). Resources: Figure volts amps watts for water heater How electric water heaters work 2) Turn off electric power. Open compartment on side of tank and look at watts and volts printed on end of each element. Volts shown on label should match the volts shown on element. 3) Volts: Replacement element should match volts shown on label on side of water heater. 4) Watts: when selecting element, buy same wattage or less wattage. Some tanks have higher wattage on upper element, and lower wattage on lower element... might save money. 5) Density: All new water heaters come with high density elements. Replace with high or low density as long as watts and volts are same. No loss of efficiency choosing either low or high density. Lower watt density tend to last longer. Lower wattage can also last longer. Foldback elements including Camco 5-year warranty elements (shown above) are for problem water with high mineral content Resource: How to replace element on electric water heater Resources for photovoltaic solar panels: Yes. Ordinary element will work with Solar Panel (DC photovoltaic). Elements work fine, However DC amps melt thermostats Read how to convert AC water heater to DC/ high voltage Convert AC water heater to DC/ low voltage

Recovery is same for high and low density: Recovery is how fast the heater can reheat a tank of water after hit water use. GPH gallon per hour recovery for ELECTRIC water heater = Watts divided by [2.42 x temperature rise in F°] Thermostat set to 125°F: 4500 watt divided by [2.42 x 60° rise in temperature] = 31 GPH recovery in summer Winter: 40° incoming water temperature. Thermostat set to 125°F: 4500 watt divided by [2.42 x 85° rise in temperature] = 21 GPH recovery in winter Recovery calculations for Electric water heater/ summer and winter: A) Typical residential non-simultaneous water heater with 4500 watt elements. Summer: 65° incoming water temperature. Resource: Average temperature shallow ground water B) Residential water heater converted to simultaneous wiring where both elements can heat at same time Install 2 - 5550 watt elements each connected to a separate 30 amp breaker. Resource: How to wire simultaneous water heater Summer: 65° incoming water temperature. Thermostat set to 125°F. Resource: How to adjust water heater temperature 11000 watts divided by [2.42 x 60° rise in temperature] = 75 GPH recovery for simultaneous water heater in summer Winter: 40° incoming water temperature. Thermostat set to 125°F: 11000 watt divided by [2.42 x 85° rise in temperature] = 53 GPH recovery for simultaneous water heater in winter Increase recovery by raising thermostat Raise recovery by changing thermostat setting. Resource: How to adjust water heater temperature Upper and lower thermostat can be set differently. A timer can be used to control temperature differences, and save money by toggling the water heating capacity depending on peak usage times. Resource: Use timer to control thermostats

Watt density

If elements burn out frequently ....