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Thread: Which Elec HW Heater?

  1. #1

    Default Which Elec HW Heater?

    With all the recent chatter abt electric tanks, I am beginning to reconsider...

    We're going geo with DSH and 40 or 50 gal storage tank to feed the main HW heater. Orig that was to be propane-fired with quick recovery. We already have big propane tank installed, and what it will be connected to is dwindling.

    Now I'm wondering if going electric for the DHW tank would be better--meaning more efficient, less expensive to operate and maintain.

    Can anyone make comparisons between NG sealed combustion and electric -- and if electric, which is the best-made, best-engineered tank to get?

    Thanks for the help! --Mark

  2. #2
    Moderator & Master Plumber hj's Avatar
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    Default heater

    Never heard of an electric heater that was cheaper to operate than gas, unless you are in the TVA with heavily subsidized rates.

  3. #3
    Homeowner Thatguy's Avatar
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    Quote Originally Posted by mark_g View Post
    Can anyone make comparisons between NG sealed combustion and electric -- and if electric, which is the best-made, best-engineered tank to get?
    What is the Heat of Combustion (the Heat Value) for NG, how efficient (80%?) are NG heaters, what do you pay for NG per cubic foot and per therm, how important is recovery time to you (your 'utility' for recovery time)?

    I pay $1.10/therm for NG and with presumed 80% effic. I pay $1.40/therm. A therm is 29.3 kwh and I pay 16cent/kwh so I'd pay $4.60/therm for elec. water heat.

    With two of us, recovery time is not a problem.
    Last edited by Thatguy; 04-24-2009 at 12:01 PM.

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    Master Plumber Redwood's Avatar
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    Efficency?
    Electric water heaters are 100% efficient.

    However,
    The cost of electricity is quite a bit higher than gas...

    Note: They burn Nat. Gas to make electricity!

  5. #5
    Homeowner Thatguy's Avatar
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    Default approximately,

    1 Therm
    = 0.87 gal of fuel oil
    =97 cubic feet of natural gas
    =1.1 gal of propane
    =29 kwh of elec heat
    =8.4 kwh of heat pump heat

  6. #6

    Default

    We have propane, not natural gas. And prices were averaging $2.78/gal until our last fill-up at $3.25/gal.

    Electric has been running Summer $0.125 and Winter $0.110 /kwh.

    We're debating between propane or electric. From your explanations, in real life it sounds as if propane at $3.13/gal wd then equal the cost of electric at 12/kwh for heating water. When propane exceeds that price, it is more expensive per therm.

    Does anyone make a dual fuel domestic tank hw heater? Or better, a triple fuel (elec, propane, wood)?

    Given that the costs are so close, would you heat your water with propane or electricity?

    Thanks for feedback! --Mark

  7. #7
    Homeowner Thatguy's Avatar
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    Quote Originally Posted by mark_g View Post
    We have propane, not natural gas. And prices were averaging $2.78/gal until our last fill-up at $3.25/gal.
    $3.58/therm

    Electric has been running Summer $0.125
    $3.63/th

    and Winter $0.110 /kwh.

    We're debating between propane or electric. From your explanations, in real life it sounds as if propane at $3.13/gal wd then equal the cost of electric at 12/kwh for heating water. When propane exceeds that price, it is more expensive per therm.

    Does anyone make a dual fuel domestic tank hw heater? Or better, a triple fuel (elec, propane, wood)?

    Given that the costs are so close, would you heat your water with propane or electricity?
    Check your propane bill for the actual heat value.

    I guess I'd look at the recent past to try to predict the near future for prices.

    There may be more maintenance issues with propane and its efficiency is less than for elec.

  8. #8

    Default

    I just contacted my energy providers and here is what my calculated cost per therm will run me.
    Electricity, Summer rate $2.97 per therm
    Elcetricity, Winter rate $1.98 per therm
    Propane $2.80 per therm (adjusted for 80% efficency)
    My electric cooperative also has a program that gives me a $4.50 credit during July, August and September if they install a radio controlled switch on my water heater. They would cut power during peak demand periods, excluding week-ends and holidays. Not a huge savings, but it does help offset my cost somewhat during those months when rates are at their highest.
    So, if my calculations are correct, having an electric water heater, especially a higher end unit like my Marathon appears to be not too bad of a choice. Factor in the savings of not installing a flue or having it sucking heat out of the house 24/7 and not having to worry about gas leaks or clogged air filters on the Flame Lock or a tank rusting through then my Marathon looks pretty good. If their fittings leak and they honor the lifetime warranty I'll be happy to swap mine out.

  9. #9
    Homeowner Thatguy's Avatar
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    Another happy forum member!

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