Maintain your water heater
is a self-help site
| How to install point of use water heater |  |
| How to install and troubleshoot garbage disposal |  |
| How to install recirculation system |  |
How to maintain water heater
|
Home
Search waterheatertimer.org / all results Search using
  
Follow newest ideas on Pinterest |
How much hot water does bath or shower use? |
 Take showers instead of bath. Does not include maintenance, installation, purchase, repair, replacement of water heater... which can substantially add cost to final energy numbers. All costs and decisions are energy. |
Regular bath uses 15+ gallons
hot water Princeton 60" x 30" x 14" insulated bathtub Filled to overflow, the tub holds 42 gallons according to American Standard. Note: 60" x 30" x 14" is rough-in dimension of bathtub... and not interior space filled by water. Note that many bathtubs are larger, such as 60" x 32' x 16" and these tubs hold proportionally more water. Body displaces water, so bathtub is not filled to overflow when taking bath. >Moderately large person sitting in tub displaces about 20 gallons, so if tub holds 42 gallons, then amount of water used for bath is roughly 20+ gallons of water. Summary: 20 to fill tub + 20 for displacement = 40 gallons which rises almost to overflow when person sits in 60" x 30" x 14" bathtub. Water level where person sits is 8-1/2" deep; measured next to hip of person sitting in tub when water level reaches overflow. Water level measured at tub drain is 1" deeper, or 9-1/2". Typical water temperature of bath or shower is 103-105°F. Typical water heater thermostat is 120-125°F. Typical incoming cold water temperature might be 50-60°F. If 5 gallons of 50°F water are added to 15 gallons 120°F water, it yields 20 gallons 102°F water. So the hot cold ratio can be approximated: 75-80% hot to 20-25% cold Resources: Compare gas and electric water heater timers Off peak water heater options Set timer chart for electric water heater 9 ways to save with water heater How to increase amount of hot water Buy: Bathtubs and shower stalls at Amazon |
|
| Electric water heater rated 240 Volt 4500 watt will
heat 21 gallons of water per hour based on 60 degree rise in
temperature/ 240 Volt 3500 watt will heat 16 gallons per hour. Gas water heater will typically heat 41 gallons per hour based on 60 degree rise in temperature. For example if water inside tank is 60 degrees F at start time, and you want 120 degree water, this would be a rise in temperature of 60 degrees. |
The
20 gallon shown above was measured after a normal bath. Measuring
technique: using small bucket to fill 5 gallon buckets (to within 3/4"
from top rim of bucket same amount when you open 5 gallon paint). Measurement shows 20 gallons of water is used for each bath.... .... estimate 15 gallons of hot and 5 gallons of cold. The hot-cold estimate 75% based on 105° bath and based on position of handle when filling tub. Temperature of incoming cold water is colder in winter and warmer in summer. Amount of cold water added to hot also varies winter-summer. Plus water heater energy-consumption varies winter-summer as more energy is needed to heat colder water. To average the variables, I estimate an 'average' year-round cold water temperature of 60 degrees. See groundwater temperature map Hot water consumption of 15 gallons for each bath is estimated based on 120 degree thermostat setting. If water is hotter than 120 degree, then less hot and more cold would be used... but the energy and cost to heat water would be comparable when baths are same temperature, with slight energy savings per bath if thermostat is set lower. Also using mixing valve located at water heater can reduce energy consumption. |
|
| Formula for
heating water inside tank: Gallon Per Hour (Electric) = (KW x 3413) divided by (temp. rise x 8.25) or (KW x 414) divided by (temp rise.) Let's say you have 5500 watt elements. let's say incoming water temperature is 65°F and you want to heat tank to 105°, or 40° rise in temperature. 5500 watt or 5.5Kw elements x 3413 = 18771.5 40 degree temperature rise x 8.25 = 330 So in this specific situation, the element would heat 56.88 gallons per hour This number is for EACH element, but does NOT consider heat loss from tank, room temperature, or thickness of insulation etc. Remember, with residential simultaneous tank, only ONE element is ON at one time. Upper element is ON, or lower element is ON, or BOTH elements are off. At no time are both elements on. |
||
| Cost
of 1 bath: 60x30x14 insulated bathtub Assumes Temperature rise 60° Incoming water temp 60°, raise to 120° hot water inside tank Assumes 15 gallon of hot water needed for regular bathtub Total 42 gallon bathtub to overflow Displacement 20 gallon for person Total water consumption 20 gallon Hot water 75% to 80% with thermostat set at 120° Total hot water consumption for this bath is 15 gallons These estimates are conservative, based on fairly large person in tub, and tub not filled to overflow Also this is the small bathtub with outside dimensions 15x30x60 |
Cost
of hot water for 1 bath/ Tank Electric water heater It takes .146666 Kwh to raise 1 gallon 60° .146666 Kwh x 15 gallon = 2.19 Kwh per bath Divide 2.19 Kwh by efficiency rating of water heater, then multiply by cost per Kwh hour you pay. *For example, typical pre-2015 electric water heater efficiency is 96%: So 2.16 Kwh ÷ .96 = 2.25 Kwh x 15¢ per Kwh = cost 34¢ per bath *For example, typical 2015 electric water heater efficiency is 99%: So 2.16 Kwh ÷ .99 = 2.18 Kwh x 15¢ per Kwh = cost 33¢ per bath |
Cost
of hot water for 1 bath/ Tank gas water heater 1 therm = 100,000 BTU Cost per therm .42-1.10 1 BTU to raise 1 lb of water 1°F 15 gallons of water = 125 lbs Raise 125 lbs water 1° = 125 BTU Raise 125 lbs 60°F = 125 BTU x 60 = 7500 BTU 1 BTU = .00001 therm *For example, typical pre-2015 gas water heater efficiency .61 So 7500 BTU ÷ .61 efficiency = 12295 BTU for 1 bath 12295 BTU x.00001 therm = .12295 therms per bath Cost 05¢ to 14¢ per bath *For example: typical 2015 water heater So 7500 BTU ÷ .675 efficiency = 11111 BTU for 1 bath 11111 BTU x .00001 therm = .11111 therms Cost 05¢ to 10¢ per bath depending on cost of therms |
| A water heater holds
20/ 30 / 40 / 50 / 60 / 80 gallons of hot water depending on size of
tank. Fully heated 40 gallon tank gives you 2 baths and a shower at one time. |
 Use safety grab bar on bathtub Buy: Safety grab bar at Amazon Bathtub safety grab bars Bolt on safety grab bar Shower rods Amazon |
|
 Energy cost of 1 bath using 45 gallon hot water: (10 gallons cold) Cost to raise 45 gallons of cold water from 60 degrees to 120 degrees inside a water heater tank: Typical electric water heater 96% efficiency pre April 2015= 6.88 Kwh per bath Typical gas water heater pre April 2015 Typical electric water heater 99% efficiency post April 2015= 6.66 Kwh per bath Typical gas water heater post April 2015 None of these costs factor maintenance, installation, purchase, repair, replacement of water heater... which can substantially add cost to final energy numbers. All costs and decisions are energy. |
Typical walk in tub uses up to 55 gallon hot water There are different size walk-in bathtubs Example American Standard fill height of water is 4" lower than deck of tub Seat height from floor 17" From seat to fill height is 12.5" (you sit in 12.5" water vrs 8.5" in regular tub). From textured floor to fill height is 29" My estimate is 80+% Hot to Cold ratio/ higher ratio for large tubs that take longer to fill. Filled to overflow: 60 L x 37 W = 80 gallons...25 displacement for person = 55 gal final fill/ 45 gal Hot 60 L x 32 W = 70 gallons...25 displacement for person = 45 gal final fill/ 35 gal Hot 50 L x 30 W = 60 gallons...25 displacement for person = 35 galfinal fill/ 28 gal Hot 48 L x 28 W = 45 gallons...25 displacement for person = 20 gal final fill/ 16 gal Hot Displacement for regular bathtub is 20 gallon for moderately large person. Displacement for walk-in tub is 25 gallons, or 5 gallons more than regular tub, because about 5" more of person's torso sits inside the water. You might need larger water heater, or 2 water heaters to supply enough hot water Resources: New DOE standards April 2015 Maintain your water heater 9 ways to save Two water heaters |
|
| Typical faucet delivers 2
gallons per minute. Test your water flow using 1 gallon or 5 gallon bucket, and stop watch on cell phone. |
In regular tub, person can lean back at 26 degree
angle -or- displace more water by sliding torso deeper into water by
lifting knees, and the water level can rise above overflow. Walk-in tub the person can lean back at 26 degree angle -or- displace more water by leaning forward to immerse torso into water which can raise water level above overflow. It is important to calculate heat loss when filling large tub. Cup of coffee cools fast. If faucet flow is 3-4 gallons per minute, then fill time takes 4-18 minutes depending on tub. Anticipate using more hot water vrs cold water when filling walk-in tub because it takes longer to fill tub, so more heat is lost while waiting for tub to fill. Offsetting heat loss during fill, is insulation value of walk-in tub vrs inexpensive steel tub, and deeper water in walk-in will hold temperature longer, and less overall surface area of walk-in will lose heat more slowly. Bubbler will cool water more quickly. Energy cost of running 1 Hp blower motor, and heat loss when using blower are not calculated, nor energy cost of any blower heater. Floor loading 725 lbs for smallest size to 877 lbs for largest size. Subfloor reinforcement recommended and not included in energy calculations. All costs are energy. |
|
| Cost
of 1 bath: Large walk-in bathtub Assumes Temperature rise 60° Incoming water temp 60°, raise to 120° hot water inside tank Assumes 45 gallon of hot water needed for walk-in bathtub Total water consumption 55 gallon Total Hot consumption 45 gallons |
Cost
of hot water for 1 bath/ Tank Electric water heater It takes .146666 Kwh to raise 1 gallon 60° .146666 Kwh x 45 gallon = 6.6 Kwh per bath Divide 6.6 Kwh by efficiency rating of water heater, then multiply by cost per Kwh hour you pay. *For example, typical pre-2015 electric water heater efficiency is 96%: So 6.6 Kwh ÷ .96 = 6.875 Kwh x 15¢ per Kwh = cost $1.03 per bath *For example, typical 2015 electric water heater efficiency is 99%: So 6.6 Kwh ÷ .99 = 6.66 Kwh x 15¢ per Kwh = cost $1.00 per bath |
Cost
of hot water for 1 bath/ Tank gas water heater 1 therm = 100,000 BTU Cost per therm .42-1.10 1 BTU to raise 1 lb of water 1°F 45 gallons of water = 375 lbs Raise 375 lbs water 1° = 375 BTU Raise 375 lbs 60°F = 375 BTU x 60 = 22500 BTU 1 BTU = .00001 therm *For example, typical pre-2015 gas water heater efficiency .61 So 22500 BTU ÷ .61 efficiency = 36885 BTU for 1 bath 36885 BTU x.00001 therm = .36885 therms per bath Cost 16¢ to 40¢ per bath *For example: typical 2015 water heater So 22500 BTU ÷ .675 efficiency = 33333 BTU for 1 bath 33333 BTU x .00001 therm = ..33333 therms Cost 14¢ to 37¢ per bath depending on cost of therms |
 |
Shower
uses
6 - 8
gallons of hot water (10 gal water total) To check amount of hot water used during a shower taken in bathtub, stop the drain and then take shower. After shower, measure the amount of water in tub, or roughly compare with the 20 gallon depth of water needed to take bath. To check hot water usage when shower is taken in a shower stall, put stopper over drain, seal with duct tape. Tape will hold stopper in place when pouring water into shower. Add water to shower. Use measured amount of water to fill bottom of shower. Do not flood water over the top. This will give a baseline amount of water. Then remove taped stopper. Use stopper again during regular shower. No need to tape the stopper when taking a shower since water will be dropping from above and will not move the stopper. When water reaches same point as the measured test, remove stopper and release water. Estimate if you are half-way through shower, and then estimate how much water the total shower would use. If temperature of water heater is set at 120 degrees, you can probably estimate 75% how and 25% cold. But more accurate way is to look at position of shower valve and see what percentage of cold water is being added to hot to temper the shower. Set water heater timer for 20-30 minutes for hot shower Resource: Family chart for setting timer Buy: Shower stalls at Amazon Home energy savings books at Amazon |
|
Shower
head flow rate
Typical bath or shower is 105° F |
||
 Shower shut off |
Product
that can save
money: use shower shut off Save 20¢ per month Stop drips. If shower drips when valve is off, and valve is off in center position, or if double handle faucet leaks on hot side, then hot water is leaving tank and new cold water is entering tank. Reduce flow. Reduce consumption. If shower head is turned off between lather and rinse, this action will save water and save hot water Remove shower head. Apply teflon tape to threads. Install shut off. Apply teflon tape to shut off threads. Re-install shower head. Buy: Shower shut off at Amazon Resources: Water-loss-with-one-drip/ pdf |
|
 |
Clean
shower and doors with White
vinegar or CLR calcium and rust remover Buy: CLR shower cleaner Amazon Shower stalls at Amazon |
|
 |
Pour
bath water into rain barrel Use 5 gallon bucket to empty tub and pour into rain barrel Cut off top of 55 gallon drum and leave lip around edge for screen Cover top with hardware cloth and then window screen to keep out mosquitoes Add 2 pints Hydrogen peroxide occasionally to disinfect/ deodorize Buy: Order 1" bulkhead fitting, and drill 2" hole, uses 1" IP Bulkhead fitting at Amazon 55 gallon barrel Amazon Rain barrels Amazon |
|
 |
What
is water worth? If you had to carry each gallon from the river up to your 2nd floor bathtub, when would you start to conserve? Average home uses 1/2 acre-foot water per year. 135,000 gallons = 27,000 5-gallon buckets Read about growth and electric consumption |
 Larger image |
Set rain barrel
higher than 550 gallon tank Use bulkhead fitting to tap into rain barrel Use 1-1/4" PVC water line to connect rain barrel to tank Tank must be on flat concrete pad. Cover top of rain barrel with hardware cloth to protect animals from falling into tank. Use gutter to channel water to rain barrel. Pour bath water into 55 gallon barrel using 5-gallon buckets Low pressure water timer |
 See example chart |
Old sizing chart Post 2015 heaters require high tech for sizes over 50 gallon Take showers instead of bath. Save 10 gallons hot water each time. To achieve same hot water consumption as previous heater withut buying more expensive heater install 2 water heaters, cut consumption, maintain heater, turn up thermostat temperature Two water heaters 9 ways to save with water heater Maintain water heater How to adjust themostat Ways to increase hot water Calculate first hour delivery |
 For large bathtub, use 80 gallon first hour |
What size
water heater? Size chart shows First Hour delivery rating First hour is capacity of tank at peak-usage times. For example at night when everybody is taking a shower or bath Increase amount of hot water with changes and maintenance How to adjust temperature How to increase amount of hot water How to maintain water heater Homes with garden tub, whirlpool bath, or oversized tub = first hour 80 gallon |
 Avoid oversized bathtubs. It's not cheap to heat all that hot water. Buy a spa. Drive to ocean and support tourism. |
What size
water heater for oversize bathtub? Large bathtub / whirlpool tub Recommend 80 gallon first hour delivery Electric: minimum 60-to-80 gallon size just for that one tub Gas: minimum 50 gallon size just for that one tub Electric heat pump water heaters generally cannot produce enough hot water. Tankless promise unlimited hot water, but temperature of water is 120 F and water in tub may be cool by time tub fills. Cost of maintenance and repairs never pay back. All costs are energy. Troubleshoot Rheem tankless |
 Safety resources How to adjust temperature on water heaters 180° scald is potential fatal injury  |
|
 |
How to install gas water heater How to install electric water heater Troubleshoot gas water heater Troubleshoot electric water heater |
 |
Support
the economy: Buy water heaters from my associate links: 50 gallon Gas water heaters at Amazon 40 gallon gas water heaters at Amazon 50 gallon Electric water heaters at Amazon 40 gallon electric water heaters at Amazon Hybrid / heat pump/ water heaters at Amazon Resources: How to install gas water heater How to install electric water heater Troubleshoot gas water heater Troubleshoot electric water heater Point of use water heaters |
|
|
|
||||||
 Contactors/ relays |
|
|
||||||
|
|
|
 |
Buy Electronic parts Industrial supplies Tools and home improvement Home and garden Hayward pool Pentair pool Southwire electric |
 |
Buy
Tools DEWALT Black and Decker Stanley SKIL Makita Porter-Cable Bosch Irwin Hand tools Klein hand tools Fluke electrical testing Dremel hobby tools Campbell Hausfeld air powered Tekton automotive Powerbuilt automotive Saws and saw blades |
 |
Resource: Compare box timers DPDT timers Intermatic Control water heater w/ Z-wave |
 |
Resource: Intermatic control centers: and parts Digital control centers and parts Tork control centers and parts Subpanels All control centers and parts Enclosures |
 |
Resource: Programmable timers Countdown timers Off delay timers On delay timers Timer modules Din rail Twin & one-shot Woods Intermatic Tork |
 |
Recirculation systems |
 | Buy
from my affiliate links every time/ thanks: Amazon As an Amazon Associate I earn from qualifying purchases Enter Amazon from any link on my site, fill cart with any item ... purchases pay small commission E-mail: geno03245w@gmail.com My response might end up in spam folder, check email folders Waterheatertimer on Twitter Message thru facebook |
