Water heater electricity usage?

My husband and I just bought a house and it has two 50 gal. Electric water heaters. One water heater runs the washer (but I always wash with cold), the downstairs bathroom (it never gets used), and the kitchen sink and the dishwasher. The second water heater runs the two upstairs bathrooms. There are two adults and a baby in the house. My question is how much energy am I wasting by having two? Does the fact that each one runs separate things cancel out the fact that I have two? Or would it be more beneficial for us and save us money on our electric bill to run everything to work off just one? We live in a 2-story, 2600 sq ft house and our electric bill is creeping up and I am trying to figure out how to decrease our kwh/day. The month of June we used right under 1500kwh for the month, but July we used 2017kwh making our bill jump up $60.

9 Answers

  • 8 years ago
    Favorite Answer

    Okay, let's look at what you have and how to use it efficiently.

    First, the problem with electric water heaters is that even if you don't use water, the thermostat in the heater will trip on to heat the water, which cools due to heat loss from the tank. This is wasted energy and this is what you have now.

    Electric tankless heaters are expensive and are power hogs. They require a dedicated, 220 volt, 60 amp circuit to operate, versus a 220 volt, 30 amp circuit for each of the water heaters you have now.

    If I was in your position, this is what I would do.

    First, I would pick the most centrally located water heater as the main heater. I would reroute my hot water supply so that all my hot water comes from that heater.

    Second, I would re-plumb the second water heater so that the hot water from it, feeds the cold supply of your main water heater.

    I would leave the second water heater off, unless I had a situation that required huge quantities of hot water, such as guest showering, and doing laundry and dishes at the same time.

    This would leave you with only one, normally operating water heater, but you would have a second heater in reserve if you needed it.

    When I re-plumbed my home, I built a system similar to what I described. It works like a dream and our additional electrical cost for heating water is never more than 30% more than with just one water heater.

    The initial cost for plumbing may be high, but you'll make it up in the long run in electrical utility savings.

    Source(s): Experience
  • Dan B
    Lv 7
    8 years ago

    Without really knowing the layout of the plumbing it sounds like you could have two separate hot water systems. Tying the two systems together may or may not be feasible. How far apart are the water heaters located? If in the same location or close, bypassing one of the water heaters (and removing it) would be easy. A plumbing contractor will have to evaluate that option.

    It takes power just to maintain the water temperature in the water heater even if no water is used. So, with two heaters, you're using 2x as much power to maintain that temperature. Water heaters are poorly insulated, maybe an R-value of 5. Adding an external insulation blanket will help a little more.

    Hot water use habits will go a long way to save money on heating that water. Don't turn on the hot water tap if you don't plan on using any hot water. Sounds dumb, but sometimes people will turn on the hot water for a short duration, but not long enough to get hot water out of the tap. But when that happen, cold water enters the bottom of the water heater, lowering the temperature of the water and maybe causing the heating element to heat the water.

    Set the thermostats on the water heater to 120 deg. That's hot enough and saves electricity. There's a slight increased risk of Legionaire's disease, but not much. If you are concerned, go to 125 deg. My water heater has letters, not actual numbers for temperature control. Even with numbers, they are not that accurate. Use a thermometer at the tap to see what your actual temperature is. Several adjustments over several hours may be necessary to get it right.

    Timers may help save if the home is empty during the day (both of you work). With a baby, you're going to use a lot more hot water than normal.

    If you go on vacation, turn off the power to the water heater. It takes about 30 minutes for the water to heat back up. Don't forget to reset the timer if you had one installed.

  • 8 years ago

    Our utility says an electric tank costs $75/month to operate - - - - think that is way high as our total electric bill is seldom over $100.

    SInce your hot water is already "zoned" sounds like you're a candidate for tankless water heater(s) - I'd probably replace the first one immediately and wait for the second one to go bad.

    In the meantime, make sure the temps aren't set too high: our 55 gal. electric came from the factory set at 165. . . . . . no need for it to be more than 130. On ours, you turn-off the power, remove two side panels and a bit of insulation beneath to find the heating elements and thermostats: set both to the same temp. Note: bacteria can grow in the heater - 130 or above kills it - we used a cooking thermometer to check our settings - tank is set at 125 but water at tap is 130. This is another reason not to use a timer: the warm water - but less than 130 when timer is Off - provides a perfect environment for bacteria.

  • 4 years ago

    The reason it shot up is considering that you turned it off for 2 days. Whilst you became the breaker on it went to work and started heating the cold water that had gone into it over the two days it was off. You have got to recognize that the water coming into the water heater is normally beneath 40 levels at this time of the year. In the summertime the water is most commonly 80 degrees. There may be nothing improper with the water heater. Now, how are you retaining your residence heat? Electric or fuel? Have you ever factored that in?

  • How do you think about the answers? You can sign in to vote the answer.
  • Steven
    Lv 6
    8 years ago

    One suggestion is that you can put one or both on timers and switch it off at night. I don't know the amount of electricity they use but it is significant. Another solution is to replace them with a on demand water heaters. They are Tank-less water heaters. You just make sure you get one big enough. They only come on when you use the water and then the shut off. The only thing is the water will take a little longer to heat up. Also keep in mind that most of the kind big enough for that are going to be 220 and will require a 220 volt service there. If you have gas in your house consider getting a gas on demand heater.

    I went through this on the kitchen water heater. I ended up using a timer as it would have required additional wiring etc to run an on demand heater. No gas line available either.

    Hope this helps

    Source(s): Do most of my own plumbing and electrical. I just don't crawl under house or in attics. I'm old but I know stuff. LOL
  • 8 years ago

    Get rid of one. And timers don't save any money as you have to bring the temp up so much when it has cooled all night. Once up to temp, it may only cycle a couple times through the night. And on demand water heaters are a losing game. They cost too much to begin with.

    Source(s): I am a plumber that knows the reality of things.
  • 5 years ago

    I prefer to recommend you to change the solar water heater, and the electricity should be the affiliate energy, first, it will use solar energy only, less energy consumotion. On the other hand, it is much more safe than electricity. anything is possible, danger surrounding all the time. Hope you will like.

  • Athena
    Lv 5
    8 years ago

    Its hard to tell without more info than this. If you want to save energy then install a device to Generate Energy from Home and use it for the water heaters.

  • 8 years ago

    If they are in the same room com you could certainly re-pipe them, using one will use less electricity to maintain temperature when not using water, the main threat would be running out of hot water, but one 50 gallon tank should work just fine for two adults.

    You could pipe them in series like shown on page two of this RHEMM technical bulletin, you could leave the first off to see if you have enough capacity, then tun it on if you have guests and need more capacity. http://www.google.com/url?sa=t&rct=j&q=&esrc=s&sou...

Still have questions? Get your answers by asking now.