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DHW -- Oil vs Electric, getting closer to real numbers.

Post in 'DIY and General non-hearth advice' started by BradH70, Nov 20, 2012.

  1. BradH70

    BradH70 Feeling the Heat

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    Ok, so I have just about run this topic dry (no pun intended), but......

    I am starting to come up with some real figures for electric vs oil to generate DHW. I have been trying to schedule my oil deliveries when the oil tank gauge is between the E and 1/4 lines and I get only the minimum delivery of 125 gallons. That way I can pretty accurately tell how long it takes to use up the 125 gallons to heat the water.

    In the house are me, my wife a 3 year old and a 4 month old.

    So I had another delivery yesterday of 125 gallons. Based on the delivery history on the slip, over the past 20 months (actually 19 months and 28 days) I have used 500 gallons of oil (and no, I did not include this most recent 125 gallons in that figure) to generate our hot water.

    So that means we are using 25 gallons a month and at the current rate of $3.69 / gallon that is $92.25 per month to heat the water.

    This is starting to make feel even more inclined to switch over to an electric hot water tank. Considering that my system is in the range of 55-65% efficient for making DHW, that works out to be in the range of $50 - $60 dollars for electric. PSNH claims $68 a month for a family of four, but I bet this is on the high end.

    So using my numbers, that is a saving of $32 per month. I'm thinking of hiring a plumber to install the new electric tank so I'm guessing that the install will probably run in the range of $750 - $1,000 with the cost of the tank included in that. Worst case is a 2 1/2 year payback. I could probably make this better by adding a timer to the water heater so that it is not heating water during the night.

    Now, what is the best electric water heater for the money? I don't want and on demand system, I want a storage tank. Are the $350 HD specials as good as the new fancy fiberglass ones? The spec sheets all seem to show the same performance, no matter the type of tank.

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  2. bbfarm

    bbfarm Minister of Fire

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    We bought a cheap $300 hot water heater with an 8 year warranty on it. It is 16 years later and still working. It is starting to leak a bit, but we got our money's worth out of it.

    If you have soft water they will last longer
  3. ScotL

    ScotL Feeling the Heat

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    If you have hot water baseboard heat installed in your house, I'd look into a Kedel. I've been pretty impressed with them. But, it would take a lot more research to determine the cost of using pellets for your DHW. It's also a much larger investment.
    I've been heating my DHW with my Harman boiler for the last 3 years, but I may be a little wierd that way.
  4. BradH70

    BradH70 Feeling the Heat

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    Wow, that looks very nice, and expensive. I already have two pellet stoves that heat the house quite nicely. My oil furnace is only 9 year old so ripping it out would be silly, plus, having the oil furnace as a backup is a good idea.

    I'm just looking to cut back on oil usage as much as possible and the DHW is were it is at right now.
  5. velvetfoot

    velvetfoot Minister of Fire

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    I flogged this topic to death as well here and other places:
    http://www.hearth.com/talk/threads/comparison-of-dhw-oil-indirect-vs-electric-tank.89754/ .

    I wound up putting in a 40 gallon (there are only 2 of us) cheap model from HD, and put some more insulation on it. I also set it on a 2" thick piece of foam. I installed it myself in parallel with the indirect so that the indirect could be used, say, in the event of a prolonged power outage.

    My reading disuaded me from using a timer for the electric. They don't lose that much heat overnight.

    For two months, I've used 59 and 41 kwh more than last year. I don't think the 41 kwh is representative since we were traveling. So, assuming, like, 60 kwh a month more electricity, times about $.10/kwh incremental, it's 6 bucks more a month. I figured I used, maybe 3/4 of a gallon of oil a day for heating dhw, so even if that was 1/2 gallon a day it comes to around $50 bucks a month, a savings of $44 per month. So even conservatively, for what I recall to be a $300 water heater, it's like an 8 month payback for me.

    I considered a heat pump water heater, but I'm in the northeast, and they seem best suited for warm climates. My basement is already cold enough in winter and I insulated the walls. Plus they make noise and have more moving parts to break, and they're not cheap, even with a rebate.
  6. velvetfoot

    velvetfoot Minister of Fire

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    Thanks for the kedel link. Pretty nice.
  7. BradH70

    BradH70 Feeling the Heat

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    Sounds pretty convincing, especially reading through the linked thread that you supplied. I think I might give some local plumbers a call and see what their opinion is.
  8. saladdin

    saladdin Feeling the Heat

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    Stay away from heat pump where you are unless the technology has really changed in the past few years. I live in TN with our winters being mild. Anything below 40 and the heat pump would struggle.
  9. saladdin

    saladdin Feeling the Heat

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    What's your cost per KWH?
  10. BradH70

    BradH70 Feeling the Heat

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    sladdin, nope, I was not thinking of doing a heat pump. My basement stays in the 50-55* range year around, which is right at the lower limit for a hybrid water heater. I'm thinking of getting a 40 gallon tank with a 9 year warranty. They are around $350 + install. I've never really done any plumping, so I may high someone to install it.
  11. BradH70

    BradH70 Feeling the Heat

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    My electric rates here in NH are 14.89 cents per KWH.
  12. Wachusett

    Wachusett Feeling the Heat

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    I have been considering the same thing (propane vs. electric). Spoke to a plumber and electrician, both said propane will recover faster. However the PHW is barely 60% efficient. Considering a Marathon brand fibergalss tank (electric) it's pricey, but has extra insulation and is less effected by hard water. Haven't had much luck finding a detailed cost comparison calculation that takes into account efficiency, recovery and stand by heat losses.
  13. velvetfoot

    velvetfoot Minister of Fire

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    There are those yellow stickers attached to the units. You should be able to find them on line.
  14. BradH70

    BradH70 Feeling the Heat

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    I think I may have given the incorrect electric rate for PSNH --- it appears that it may be lower then I had stated, but the rate are changing to 8.97 cents per KWH January 1st.

    this is the chart that I went by to figure the electric rate:
    Rate R, Residential Service
    Available to customers living in individual residences
    and apartments.
    Customer Charge $11.96 Per Month
    KWH Distribution Charge 3.905 Cents per KWH
    KWH Transmission Charge 1.480 Cents per KWH
    KWH Stranded Cost
    Recovery Charge 1.999 Cents per KWH
    System Benefits Charge 0.330 Cents per KWH
    Electricity Consumption Tax 0.055 Cents per KWH
    Energy Charge 7.11 Cents per KWH





    Also, I just called a local plumber and talked to the receptionist. She mentioned that they deal primarily with oil/gas boiler systems but would be willing to give me a quote since they have done some work for me when I need an additional zone connected to the furnace. She also told me that an electric water heat is going to be substantially more expensive then the BoilerMate system that I currently have. I'm am now very anxious to speak with the owner of the company about the switch and see what he thinks.
  15. saladdin

    saladdin Feeling the Heat

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    I've considered the hydrid water heater. The ones I eyed needed their own room (very few basements in the south) and were around 1k.

    Don't short yourself. Check out some youtube plumbing videos. I bet you could do it. I've had electrick water heaters my whole life and have installed before. Not that big of a bear.
  16. saladdin

    saladdin Feeling the Heat

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    Jesus H Christ! Sitting at around 9 cents here.
  17. BradH70

    BradH70 Feeling the Heat

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    See my next post after that. I did the math wrong, the rates now are 7.11 cent but going to 8.97 cents January 1st.
  18. SmokeyTheBear

    SmokeyTheBear Minister of Fire

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    Does that include the delivery fee?
  19. saladdin

    saladdin Feeling the Heat

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    I'm lost as to why an electric set up would be so expensive. They quoting you running the wire from the box and plumbing? If you have decent access to both you could do this.

    Wait a sec... You already have the plumbing from the existing unit right? It not plug n play with the electric unit?

    That just leaves the electricity.
  20. saladdin

    saladdin Feeling the Heat

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    This is my entire rate schedule.

    RESIDENTIAL RATES - SCHEDULE RS
    Customer Charge
    Per Delivery Point Per Month $19.46
    Energy Charge Cents Per Kwh 9.122¢
  21. saladdin

    saladdin Feeling the Heat

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    Damn that's cheap. I've never used oil, granted, but I don't see how electric wouldn't be a crap load cheaper.
  22. BradH70

    BradH70 Feeling the Heat

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    Here is the summary of rates as PSNH gives them. Maybe someone can help me decipher/calculate them. I was looking on another (new) electrical provider for NH and they show PSNH as 7.11 cents per KWH and this just happens to be the last line of.......

    Rate R, Residential Service
    Available to customers living in individual residences and apartments.


    Customer Charge $11.96 Per Month
    KWH Distribution Charge 3.905 Cents per KWH
    KWH Transmission Charge 1.480 Cents per KWH
    KWH Stranded Cost Cents per KWH
    Recovery Charge 1.999 Cents per KWH
    System Benefits 0.330 Cents per KWH
    Electricity Consumption Tax 0.055 Cents per KWH
    Energy Charge 7.110 Cents per KWH
  23. maple1

    maple1 Minister of Fire

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    I think the receptionist is mis-informed.
  24. SmokeyTheBear

    SmokeyTheBear Minister of Fire

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    Brads actual per kilowatt charges are 14.879 cents to which is added a $11.96 per month account fee.
    Your per kilowatt charge is 9.122 cents to which is added $19.46 per month account fee.

    My per kilowatt charge is 16.8538 cents for up to 100 KWh and then it drops to 14.0211 cents per KWh

    Just a few differences.
  25. BradH70

    BradH70 Feeling the Heat

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    Ok, so my brain finally woke up and I decided to go PSNH and look at my latest statement.

    There are two portions of the bill
    PSNH Delivery Services:
    KWH Distribution Chrg = 0.039050 cents
    Transmission Chrg = 0.014800 cents
    Strnded Cst Recovery Chrg = 0.019990 cents
    System Benefits Chrg = 0.003300 cents

    Electricity Supply:
    Energy Chrg - Rate R = 0.071100 cents

    Add these all up and you get 14.824 cents per KWH

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