Energy Usage, Conservation and Weather Stripping - water heater timer
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bdonherrin
04-01-09, 08:51 AM
I am looking to install a water heater timer and would like to do it myself and have done some electrical simple work such as installing lights and fans do you have any good advice that would make this a success?
airman.1994
04-01-09, 11:19 AM
Bad idea! Heating and cooling the tank will lead to the liner craking.
resercon
04-01-09, 01:43 PM
It depends where the water heater is located and if freezing temperatures are reached in that area. Thermal shock occurs when there are dramatic temperature swings. One of the factors for heat loss is the temperature difference between the water inside the heater and outside the heater. The larger the temperature diffence the greater the heat loss.
For example, if the temp outside the heater was 32 degrees Fahrenheit and the water inside the heater is at 140 degrees Fahrenheit the rate of heat loss per hour would be significant and the proability that thermal shock would occur to the materials in close proximity of the water is high provided that this occurred on a regular basis. As in the case of using a timer. However, there are several other factors we have to consider. Such as water contained inside a tank has good thermal mass.
For example if you took a hot cup of coffee outside when it freezing outside it wouldn't take long for the coffee to become cold. But if you put the coffee in a thermos the coffee would stay hot for some time. This is the principle behind the use of water heater insulation jackets.
Another factor to consider is the volume of water involved. For example if we take a cup of water out of a pot of hot water and put the cup and the pot on a table the cup will reach room temperature way before the pot will even though the temperature of the water at first were the same temperature. If we applied this to a 40 gallon tank it would take a considerable amount of time for the water in the tank to equalize with the temperature outside the tank. It would even take longer with an insulation jacket.
While there are a lot of factors I did not discuss here, I would like to leave you with this; the average electric water heater operates at 4500 watts. That is equivalent to 45 - 100 watt light bulbs. We have the audacity to tell our children to turn off the lights when they leave the room and we leave the house unoccupied during the day when we go to work and sleep with the water heater on.
Good for you for thinking about installing a timer. Just make sure the electric is turned off when installing it. Four wires that are color coded that correspond to four screws on both sides of the timer that are also color coded. Hope you're not color blind.
For example, if the temp outside the heater was 32 degrees Fahrenheit and the water inside the heater is at 140 degrees Fahrenheit the rate of heat loss per hour would be significant and the proability that thermal shock would occur to the materials in close proximity of the water is high provided that this occurred on a regular basis. As in the case of using a timer. However, there are several other factors we have to consider. Such as water contained inside a tank has good thermal mass.
For example if you took a hot cup of coffee outside when it freezing outside it wouldn't take long for the coffee to become cold. But if you put the coffee in a thermos the coffee would stay hot for some time. This is the principle behind the use of water heater insulation jackets.
Another factor to consider is the volume of water involved. For example if we take a cup of water out of a pot of hot water and put the cup and the pot on a table the cup will reach room temperature way before the pot will even though the temperature of the water at first were the same temperature. If we applied this to a 40 gallon tank it would take a considerable amount of time for the water in the tank to equalize with the temperature outside the tank. It would even take longer with an insulation jacket.
While there are a lot of factors I did not discuss here, I would like to leave you with this; the average electric water heater operates at 4500 watts. That is equivalent to 45 - 100 watt light bulbs. We have the audacity to tell our children to turn off the lights when they leave the room and we leave the house unoccupied during the day when we go to work and sleep with the water heater on.
Good for you for thinking about installing a timer. Just make sure the electric is turned off when installing it. Four wires that are color coded that correspond to four screws on both sides of the timer that are also color coded. Hope you're not color blind.
Gunguy45
04-01-09, 02:00 PM
What is the age of the WH? Newer units probably wouldn't turn on the elements if you were only gone for a normal workday, and if they did, it might take 5 or so minutes to bring the water temp back up to the thermostat setting. Might take a while to recover the cost of the parts for the timer install.
Bud9051
04-01-09, 02:24 PM
I installed one years back that cound be programmed to come on 24/7, so I thought I had it all set. Only problem was the idiots that designed the unit fordot battery backup and every time (frequently) the power went off my unit was out of sync. PIA, make sure yours has a memory.
Bud
Bud
the_tow_guy
04-01-09, 03:00 PM
Frankly, I've never been convinced a WH timer saved a sgificant amount of electricity. Newer units are insulated sufficiently that they can go long stretches before losing enough heat to turn on.
Would make a good Mythbusters experiment.
Resercon, need to check your math, dude. :eek:
Would make a good Mythbusters experiment.
Resercon, need to check your math, dude. :eek:
Beachboy
04-10-09, 12:03 PM
I think timers on electric water heaters became popular when some electric utilities offered lower rates for night time electrical consumption. In fact, I think there was a separate electric meter installed just for the water heater and the timer was used to guarantee the water heater would be on only during off peak hours. However, with regular residential electric service, I agree with Tow Guy and Gun Guy that a timer probably wouldn't pay for itself. I have a gas water heater, so I can hear when it is running, and after 25 years of living in this house, I have NEVER heard the water heater firing during a period of no water usage.