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Oil indirect or Heat pump hot water heater?

I'll be replacing my boiler/tankless coil combo this fall, and I want to decide on whether I should get a 40 gal indirect to go with the boiler, or to turn off the boiler in the summer by getting a geospring hybrid electric hot water heater. When I run the numbers they come out kind of close, so I'm not sure which I should choose.

For reference, oil in my area is about $3.39/gallon and with my old boiler/coil I uses .4 gallons/day in the summer for DHW. According to GE the Geospring in full heat pump mode uses ~1860 kWh/year for usage. Electricity in my area is 18cents/kWh, although a 6% tax hike is planned soon.

I'm concerned about the reliability of the heat pump, and I don't know if it will truly be able to run efficiently in heat pump mode all the time, especially because my basement can get cool in the winter (down in the low 50s or even high 40s when its really cold). Seems like indirect's are much simpler hot water generators, although it would be pretty nice to be able to completely turn of the oil boiler in the summer.

Does anyone have thoughts on which I should choose?



  • icesailor
    icesailor Member Posts: 7,265

    Sounds too good to be true.

    $.18 KWH per month? Is that if you use 5000 KWH Per Month? Or 500 KWH Per Month? Take the cost of your monthly electric bill and divide it into the KWH you used for that month. Utilities are deceptive in quoting cost to operate electrical equipment. You can put lipstick on the talking TV pig, but it is just a better looking TV pig that talks. An electric water heater is an electric water heater, no matter where the energy phase change occurs, Inside the heater tank or the inside of a HX coil. Its still done with electricity.

    Be careful when stepping over all those $10.00 bills scattered around when going after that broken roll of dimes someone dropped on the sidewalk. You're paying $.02438 Per BTU for oil. How much for electricity when compared? The less electricity you se, the more it cost.

    Electric water heaters last 5 to 6 years. The warranty length. They fail any time after that? How many years have you been running your oil boiler?

    Do you have perfect water where you live? Where I live, I can hear the elements sizzling any time the electric water heater is running because they are encrusted with insulating hardness.

    If it sounds too good to be true, it might be.
  • Zman
    Zman Member Posts: 7,572
    To close to call....

    If you figure your oil burner is 75% efficient, You are presently paying $24.44 per MBTU.

    Theoretically the Geospring has a 2.4 factor so you would be paying $21.98.

    In reality, depending on your usage, it will sometimes run in resistance mode and cost you $52.75 during that time.

    Other things to factor in.

    The boiler will have higher standby losses.

    The geospring gets much of it's energy from the air around it. A nice feature when installed in an overheated boiler room or in the summer. Not so good if it installed in a bedroom closet.

    My gut is that if you have relatively  low and consistent hot water needs, the gepspring is  the right choice.

    If you have a house full of tennagers or large tubs to fill, go with the indirect.

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • icesailor
    icesailor Member Posts: 7,265
    Oil Burner Efficiencies:

    I look at efficiencies like I do like the homeless man with only a dime to his name, in his pocket. If he finds a penny, his worth improved by 10%. If he finds a dime, he increased his worth by X10. If he had a dollar bill and he found a dime, he was worth 10% more though.

    I never saw any modern oil boiler with a modern flame retention head burner that ran at 75%. Playing "fun with numbers", and every new oil install was 84% to 88% on my Insight DA and the manufacturers listings of 86%.

    That add on that the Famous TV plumber installed may work fine in a hot cellar in the summer. I've seen some 55 degree cellars in the winter that I don't think would work as well. As far as I am concerned and my experienced, that thing is a tough sell. I've seen that glazed look in the eye that many people get when you tell them how much more the latest green technology item on the market will cost them instead of just replacing what they have.

    I added R-30 blown insulation to my attic. It made a huge difference as far as the equipment running. Will my investment pay off? Not in my lifetime. Whatever savings comes off the end of the bill, the lowest cost on the bill. It cost me $1700.00. Its worth it for me in comfort. Maybe not so much in cost.

    Some of us had to actually convince customers to open their wallets. Talks cheap.
  • redlr
    redlr Member Posts: 1
    icesailor said:

    You can put lipstick on the talking TV pig, but it is just a better looking TV pig that talks. An electric water heater is an electric water heater, no matter where the energy phase change occurs, Inside the heater tank or the inside of a HX coil. Its still done with electricity.

    This is not an electric water heater. This is a heat pump so as long as you do not exceed its capacity, it is not supposed to use electric to generate heat and is at least than twice as efficient as an electric hot water heater. But it does have its own issues.
    What you need to consider is how much hot water you will require during the peak hour. When three or more people take long showers at the same time, a 50 gallon unit can easily run out of hot water and that's when the electric resistance heaters kick in and you lose the efficiency bonus.
    There is also the initial cost of the heat pump. There are several rebates and things that could bring down the cost to the same level as a basic water heater, though.
    Finally, there is the reliability issue. I've seen people who think GE Geospring is bliss and others who think it's nothing but trouble. Then, there are others who say the unreliable version was the old brown model that was made in China and the new red one performs much better. All that talk kind of tells me Geospring is pretty much like gambling. It could work and perhaps it won't.
    That's why I would go with the type of water heater I am familiar with unless the savings are going to be really big.