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  1. #1
    Join Date
    Jun 2005
    Posts
    44
    I am needing to replace my hot water heater one way or the other. With everything going on with gas prices I am seriously wondering if I should replace my current natural gas with an electric. Latest gas bill is $1.15 per therm, current electric rate for me in Kansas City per kWh is 7.36 cents four months of the year, 4.30 cents eight months, or 3.39 cents if usage is over 1,000 kWh (these are heat pump rates). There are four people in our family, three girls and me. I've calculated it with 4622 kWh per year with the electric, and 238 therms for the gas. I know we can't predict gas or electrical prices, but electrical has been a lot steadier than natural gas here in the midwest. I have figured that if I go electric, that will push me above the 1,000 kWh per month so my pricing will be the 3.39 cents. That makes it cheaper (although only slightly) than gas to run. The one thing I have not calculated is that the electric should not use as much in the summer time with the incoming water being of higher temperture. I used an average rate of 385 kWh per month.
    Considerations to address---

    1. I could locate the electric to an area better suited for it and free up some space.

    2. Since I have gone with a 92% furnance, my current water heater is now "orphaned" to a 6" B-vent , I've heard conflicting stories as to if this is okay or not.

    3. Electric does not recover as fast, so will sizing to an 80 gallon electric be enough for the family?

    4. Gas heaters have historically been cheaper to operate, so do we ignore the current spike in gas prices and calculate on gas price averages?

    5. Are my calculations correct in that it will be slightly cheaper to run the electric versus the gas.

    6. I'll be doing the install myself, and even though the gas will be easier, gaining the space will offset the difference there.



    I'm confused enough thinking about this that my head is starting to hurt, so please chime in on this so I can put this issue to rest.

  2. #2
    Join Date
    Feb 2003
    Posts
    1,996
    As long as you have the spare power, go for it. Even with 80 gal, don't expect 3 girls (hope they're not teens!) to take 3 showers in a row. I still think your electric will go up if your area does not burn coal. Heck you'll need a new one in 8-10 years, so you can always switch back.

  3. #3
    Join Date
    Jun 2005
    Posts
    44
    Well in our area they mainly burn coal, also I'm pretty sure some of the power comes from Wolf Creek which is nuclear, hence our electric rates. My wife and a 6 and 11 year old, I have already taken some cold showers with a 40 gallon natural gas heater, but not since I installed the Oxygenics shower heads which are amazing! I know it's pretty much a toss up, that's why I'm looking for some votes either way--informed, opinionated, or other.

  4. #4
    Join Date
    Jul 2004
    Location
    Kent, WA
    Posts
    129
    With gas at $1.15/therm, and assuming a 90% efficient gas water heater, your electrical costs need to be about 4.5 cents per KW-Hr to come out ahead.

    To aid in recovery with an electric unit, look at the heating element watts. Usually, they are around 3300, 4500, and 5500 watts. Pick one with 5500 watts for more heat delivery.

    Do you have more gas equipment? Usually, having any utility costs you about $5/month just for the privilege of having a meter that is read. If you can totally eliminate gas, then you can get rid of that wasted cost.

    From what you've said, I can't tell which is better. It may be a wash, or flip back and forth as the price of each utility fluctuates.

  5. #5
    Join Date
    Jun 2005
    Posts
    44
    That's the problem with gas water heaters--61% efficient is the norm unless you look at tankless (which I have, the power vent is the problem as my furnance is using about the only place I can do direct vent). So the costs to operate a gas is about $238.00 a year (238 therms @ $1.00 a therm) The costs for electric breaks down to 385 kWh a month--

    1. 4 months summer rate 7.36 cents a kWh =
    (385 x 4 x .0736 = $113.34)

    2. 8 months winter rate @ 3.39 cents a kWh=

    (385 x 4 x .0339 = $120.12)

    3. total cost per year electric = $233.46

    Again this is assuming 4622 kWh a year divided equally among summer months and winter months

  6. #6
    Join Date
    Feb 2003
    Posts
    1,996
    Well, even if you have 30 or 40 AMPS available in your panel, I don't know if you'll get 4 showers back to back even with an 80 gal. Now a 120 gal tank gets very pricey.
    Before you look at a 90% gas HWH, maybe the new tankless units might be an option. They're great for continuous showers as long as you keep the draw at 2-3 GPM.

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