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102 gal of oil for 161 days of hot water. Good? Bad?

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by Ansky, Oct 7, 2013.

  1. Ansky

    Ansky Member

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    I just topped off my oil tank and it took 102 gal. My last fillup was end of April and I never touched the heat once, in fact, the thermostats were all turned off at that point,so the only thing the furnace was heating, was hot water.

    Now I know that oil in not an efficient way to heat hot water, and I'm considering going with an electric hot water heater. But I also want to figure out my breakeven point. Heating the HW with oil cost me .63 gal of oil per day. At $3.85/gal of oil, that's $2.43 a day to heat hot water. Is that bad?

    I'm curious if any one on here has done the math and knows what the breakdown is for heating HW with electricity.

    The tricky part is, that in the winter months, I'll be supplimenting my wood stove with oil heat. So, if the oil burner will be running anyway to heat the house at times, then I might as well also use it for the water as well. If not, I'll be running the oil burner for heat, and spending money on electricity to heat the water.

    What a dilemma. Any suggestions?

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  2. Nofossil

    Nofossil Moderator Emeritus

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    I have an indirect DHW tank run as a zone off my boiler. When we heated with oil, we used almost exactly the same as you for a family of five (with a teenaged daughter). Seems about right.

    The on-demand propane heaters are much more efficient, especially for intermittent use. They have almost no thermal mass so they can come up to heat instantly. There are other options as well.
  3. kopeck

    kopeck Minister of Fire

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    I was using more then that with my oil boiler and my indirect, I can't quite recall but for that time span I'm thinking double your number.

    I do have a family of 4, 2 of which are toddlers so we do more then out share of laundry, baths etc.

    I added a heat pump to the mix this summer and pretty much used zero oil. I went from $700 bucks to heat water in the late spring/summer/early fall to around $100/$150. I have to use the oil boiler now though as my heat load is to much for the heat pump and I haven't started the Tarm yet.

    K
  4. maple1

    maple1 Minister of Fire

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    So how much would the oil burner be used for heat during the winter?

    I yanked my oil all out a year ago. Put in a new 80 gallon electric hot water heater. It runs about $1/day for a family of 5 ($30/mo @ 0.16 kwh). Before that my tankless coil oil/wood boiler would use about 3/4 of a 200 gal. tank of oil for our non-heating-season DHW needs.

    Installed an electric boiler for rare heat backup

    Check out the recent 'oil backup' thread - but I would get rid of oil all together.

    (Think I'm getting kinda repetitive with that song & dance :) ).
    GS7 and STIHLY DAN like this.
  5. muncybob

    muncybob Minister of Fire

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    Of course, gonna depend on your electric costs in your area.....but I look forward to firing up my wood boiler to heat DHW as I typically see my monthly electric bill drop a min. of $30/mo. $70+/mo. just to heat water seems high to me.
    We are only a 2 person household but based on how often the washing machine runs I swear my wife is washing for all the neighbors too!
  6. kopeck

    kopeck Minister of Fire

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    I'm sure you are talking to Ansky, but in my case, while hard to prove, I think I used a lot less oil during the heating season to provide DHW. 100,000 BTUs to just heat my 30 gallon indirect or 100,000 BTUs for the indirect and everything else...

    Oil stinks for DHW, I not sure if you could find a worse way to do it.

    K
  7. maple1

    maple1 Minister of Fire

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    Yes it absolutely stinks for DHW - and it stinks about just as bad for backup heat too.
  8. Robert C.

    Robert C. New Member

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    $30 sounds just about right. I was in the same situation. First step was getting a tankless water heater in February, because it made no sense to me to pay for oil to heat water inefficiently during the summer. My bill went up like $30/month. That's the equivalent of less than 10 gallons per month. I seriously doubt I'd be using less than 10 gallons of oil to heat my water off season. No idea what my payback time will be, but I don't really care. The second step of getting off oil was to buy a woodstove of course. I plan to use no oil this winter. I have the Blaze King Princess insert. Fingers crossed!!

    Off topic, sorry, but for the stove my payoff time is one season. I paid around 4000 last winter for oil. The insert + install was around that.
  9. velvetfoot

    velvetfoot Minister of Fire

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    Here's one of the (stupid?) threads I started on this, for what it's worth:
    http://www.hearth.com/talk/threads/comparison-of-dhw-oil-indirect-vs-electric-tank.89754/

    The yellow tags on the electric heaters tell you how many kw-hrs they typically use, and it seems that the doe test procedure is based on 63.4 gallons (see thread), so I normalized mine down to 30 gals of hot water a day (2 of us, also used water meter on softener). I figured I used between .5 and .75 gal of oil per day. I figured electric was $334 a year and oil was between $701 and $1037 a year.

    Then again, if your (cable, smartphone, satellite, etc) bill is, (100, 150, etc) a month anyway, a hot shower is nice.

    I tried to not burn any oil at all last year, though, and suceeded; not so sure about this year though.
  10. Seasoned Oak

    Seasoned Oak Minister of Fire

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    Your oil HW works out to about $72.90 per Month. I have a family of 5 and our electric HWH uses no ,more than $30 a month in electric. In fact when i turn it on in the summer (once i shut down the solid fuel boiler that also heats the water) I dont even notice any increase in the bill. Im guessing the boiler with its pumps and fans use about as much as the Electric HWH.
  11. Ansky

    Ansky Member

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    Thanks for all the replies. I got my stove last Feb. I have 1 room in my house (bonus room above the garage) that the stove won't reach. So, if I were to convert to an electric water heater, I think I'd have to turn the oil burner on in Mid-Late Nov anyway. It probably won't get shut off until March. So I don't know if it would make sense to pay for electric HW when the burners running anyway. For the summer months, yeah, its a no brainer that electric is the way to go.

    My other concern was shutting off the burner for the summer months. I've read the posts on here that say that's not a good idea due to them leaking when they get cold. So, if I shut it off for the summer and substitue electric HW, am I really just opening a can of worms that will bite me in the butt later due to burner issues. Something to consider.

    I've been keeping track of my oil consumption pre and post stove. It's pretty interesting...

    Pre-Stove:
    From 10/25/12 to 1/25/13, I burned an avg of 3gal/day
    From 1/25 to 2/7 (probably the 14 coldest days of the year), I burned 4.75gal/day. WOW!!!

    Post stove:
    From 2/8 to 4/26 i burned 1.3gal/day (using some supplimental heat and HW)
    From 4/26 to 10/4, i burned .63gal/day (HW only)
  12. Seasoned Oak

    Seasoned Oak Minister of Fire

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    Watch your stove room humidity. If its over 65% you will have problems. I have to run a de-humidifier all summer to keep my basement below that or my boiler will rust.
  13. jeffesonm

    jeffesonm Feeling the Heat

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    Timely thread.

    I am currently heating DHW with a coil in a 1957 oil furnace that used ~150 gallons over the past 6 summer months, or about .83 gallons/day @ $3.59/gallon = $3/day = $90/month. In the winter I used just a tiny bit more as the wood stove provides nearly all the heat. I've only lived here a year and knew this was an inefficient way to heat water, but now that I'm doing the math, it's looking downright awful. ,

    Based on all the info in this thread, I should look into a separate hot water heater, maybe 50 or 80 gallons. It's only me and the missus and we're pretty frugal in our hot water usage. Just upgraded from an insert to a freestanding stove so I hope to heat exclusively with wood this year. No natural gas here, and I plan to do a gasifier setup in the next 3-5 years as part of a more major house renovation.

    Any recommendations on electric vs propane for the hot water heater? Anything else I should consider before pulling the trigger and hopefully turning off this oil boiler for good?
    Last edited: Oct 7, 2013
  14. avc8130

    avc8130 Minister of Fire

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    It's funny, it seems this realization about the cost of heating DHW with oil comes around every fall as people who "filled in July to buy at a cheap rate" realize heating DHW has cost them 1/4+ of their oil tank already!

    You are in NJ. That means there is no such thing as "affordable" propane from what I have found.

    Throw a 40 gallon electric in. ~$300 at HD/Lowes. For the wife and I 40 gallons gets the job done easily. We have more than enough by the time the baby needs her bath in the evening.

    ac

    PS: since you are in the boiler room, you already know what the ultimate solution is. A BOILER!
  15. avc8130

    avc8130 Minister of Fire

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    When you shut the boiler down for the season, spray it down with a rust proof-er. Just choose something that will burn safely when you fire the boiler back up in the winter.

    ac
  16. STIHLY DAN

    STIHLY DAN Feeling the Heat

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    I have already done the math for you and have the proof. I have a fam of 5 with 3 being teenagers 2 girls. Oil boiler hot water cost me $1200-$1400 a year. I live in the north east as you do. ! thing that is a must up here is a dehumidifier. I installed a heat pump 50 gal electric water heater with mixing valve. MY HOT WATER FOR THE YEAR IS FREE, ZERO!!!!!. Running the heat pump dehumidifies the basement, cheaper than running the dehumidifier. My wood furnace preheats my 80 gal tempering tank, so hot water heater does not turn on. I now brush my teeth in hot water, even going to put hot water to the toilets so no sweating.
    Normal hot water is $1000 for oil, $1000 lp $300 on demand lp $500 for electric, $189 hybrid hp, $98 hp only. This is a year basis. $300 tax rebate on hp from feds, Plus utilities tend to have rebate. From what you are paying ROI would be less than a year. My ROI was a $350 profit the 1st day. Now its just raking in the savings. Wish I did this years ago. An absolute no brainer.
    BoilerMan, maple1 and seige101 like this.
  17. Elle

    Elle Member

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    I installed an "instant on" water heater a few summers ago. It raised my electric bill by about $8-$11 a month. That was far better than the $1200 it cost to heat the water from May to September.

    This is my first winter heating with wood and I will likely turn on the oil burner in November and set the thermostat at like 50 degrees just because I don't want to freeze my bleep off on case I fail miserably lol. With it on I will use it to heat the water cause it will e on anyway. If I get good at burning I might change my mind tho

    I to have heard/ read it is bad to shut the oil totally off but it is too costly to let run in the summer so I will take my chances. I asked the guys that service it the proper way to shut if off and turn it on and they showed me. So far so good.
  18. maple1

    maple1 Minister of Fire

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    The ultimate way to get off the oil would be to do this, and put in a mini-split heat pump system for backup heat (for some that would do all their heat) AND summer a/c. If someone also regularly uses a dehumidifier too, well you could kick that to the curb too and the drain it puts on the electric bill.

    I'll say it again - break the oil habit addiction. It is a no-brainer if you use it to heat DHW, or only for backup heat, or only to heat one room - or even if you use it for all three. The numbers prove it. Factor in incentives that might be available, and ongoing oil burner maintenance & all the potential bad stuff that comes with storing all that oil in your basement or on your property - you'll wish you had done it a lot sooner.
  19. STIHLY DAN

    STIHLY DAN Feeling the Heat

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    If your boiler is less than 10 yrs old it will be fine. Its the older ones that have been constantly for more than 10 yrs that start to leek. If your going to keep it as backup change it to a cold start, if less than 10.
  20. jeffesonm

    jeffesonm Feeling the Heat

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    I am a little concerned about my boiler leaking since its 60+ years old, but I guess it's going to go sooner or later and with the DHW coming from a water heater it's really just a backup.

    Any recommendations for heat pump water heaters?
  21. woodsmaster

    woodsmaster Minister of Fire

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    Seems like a lot of money to me. I would put an electric W.H. in.
    In a few years it would pay for its self. then it's money in your pocket.
  22. STIHLY DAN

    STIHLY DAN Feeling the Heat

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    The GE geo spring is nice. !o yr warranty.
  23. BoilerMan

    BoilerMan Minister of Fire

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    It's funny really. Back in the 70s we were all about 100% electric homes, electric heat (resistance baseboard), electric range, water heater, dryer etc. Then in the mid 80s we went with our Bock direct oil fired water heaters and watched the electric bill drop and didn't mind that oil was 70cents/gal. Now we are throwing out the Bock/domestic coil and going back to electric because the high oil price has made electric cheaper again.

    Use a heat pump water heater and the electric costs half again.

    TS
  24. Seasoned Oak

    Seasoned Oak Minister of Fire

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    Nice thing about the HP -WH like a geo spring is if it can replace your dehumidifier or reduce its load enough its like free HW.
  25. Fred61

    Fred61 Minister of Fire

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    When they were building the nuke plants they were thinking that electricity was going to be so plentiful and cheap that they were just about going to give it away. Surprise it turned out to be alot more expensive than predicted. I was talked in to electric baseboard for a house I built in 1968 by a power company executive. He told me I wouldn't be sorry ------WRONG!!
    BoilerMan likes this.

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