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  1. #1
    Join Date
    Jan 2013
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    12

    Confused Fuel cost calculations?

    Can someone tell me how to do the calculations? I have a 14.5 seer heatpump with an 80 percent efficent oil furnace. I have been wondering the same thing but don't know how to do the numbers. I suspect my number to be much lower since oil is high and my furnace is not as efficent.
    Thanks

  2. #2
    Join Date
    Sep 2008
    Location
    Western PA
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    25,551

  3. #3
    Join Date
    Jun 2001
    Location
    Moore, Oklahoma, United States
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    4,186
    This is the Ask Our Pro's forum. In order to post a response here, you must have verified qualifications and have been approved by the AOP Committee. You may ask a question by starting a new thread.

    You can find the rules for posting and qualifications here.

    Additional infractions may result in loss of posting privileges.
    Last edited by jpsmith1cm; 01-20-2013 at 03:23 PM. Reason: Non AOP member

  4. #4
    Join Date
    Mar 2006
    Location
    The South
    Posts
    2,188
    If you provide your all inclusive electric rate by cost/KWH, COP preferred or even HSPF eff rating of your HP, and cost/gal of fuel oil, I can give you a good estimate to be used as a guide only.

    IMO

  5. #5
    Join Date
    Jan 2013
    Posts
    12
    It looks like I have a cop of 3.64@47F and 2.6@17F for my furnace and ecoil. I'm paying about $3.80 a gallon for oil for my 80% efficent furnace and if I read my electric bill correct I'm paying $.12 per kwh. It seems there are a lot of variables from what I have read including house and ducting insulation that factor in?

    What I am really interested in is the economic balance point at this time. I doubt I would want to run the heat pump when it's below 25F outside regardless of the economics just for comfort reasons alone but just trying to get an idea if its worth running it that low from a $$ standpoint?

    I'm sorry if this is a duplicate of similar posts but I tried to read some of the existing posts on the subject and didn't totally understand some of the termanology.

  6. #6
    Join Date
    Jan 2013
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    12
    If it makes a difference I will also add that I only have a single speed blower on my forced air system.

  7. #7
    Join Date
    Jun 2001
    Location
    Moore, Oklahoma, United States
    Posts
    4,186
    This is the Ask Our Pro's forum. In order to post a response here, you must have verified qualifications and have been approved by the AOP Committee. You may ask a question by starting a new thread.

    You can find the rules for posting and qualifications here.

    Additional infractions may result in loss of posting privileges.
    Last edited by jpsmith1cm; 01-20-2013 at 03:24 PM.

  8. #8
    Join Date
    Jan 2013
    Posts
    12
    Thanks, if that turns out to be the case the new heat pump will probably save me over $1,500 per year and that doesn't included the savings in the summer months over my 10 seer air conditioner I replaced with the heat pump.

  9. #9
    Join Date
    Mar 2006
    Location
    The South
    Posts
    2,188
    KKrace

    While you don't provide the size of your heat pump and oil furnace, you should run the heat pump as low as possible as long as you are comfortable and heat pump heat Is able to maintain your inside thermostat setting. Once inside temperature begins to drop, that is the point that you should set your changeover from HP to oil furnace. Keep in mind your furnace will come on to temper the air during a HP defrost call unless this function has been disabled.

    Here are the numbers from a fuel comparison calculator that I like to use as a guide only. I decided to use a 3 COP as an average.

    Cost per 100,000 btu of useable heat

    Electric baseboard: $3.16
    Heat pump: $1.17
    Oil: $3.44

    You can readily see that the savings when using heat pump heat are significant. Hope this helps.

    IMO

  10. #10
    Join Date
    Jan 2013
    Posts
    12
    Quote Originally Posted by tigerdunes View Post
    KKrace

    While you don't provide the size of your heat pump and oil furnace, you should run the heat pump as low as possible as long as you are comfortable and heat pump heat Is able to maintain your inside thermostat setting. Once inside temperature begins to drop, that is the point that you should set your changeover from HP to oil furnace. Keep in mind your furnace will come on to temper the air during a HP defrost call unless this function has been disabled.

    Here are the numbers from a fuel comparison calculator that I like to use as a guide only. I decided to use a 3 COP as an average.

    Cost per 100,000 btu of useable heat

    Electric baseboard: $3.16
    Heat pump: $1.17
    Oil: $3.44

    You can readily see that the savings when using heat pump heat are significant. Hope this helps.

    IMO
    Does that $3.16 per 100k btu change as the outdoor temp drops?

    Its a 3.5 ton heat pump and the furnace is 112,00 btu 80% forced air

  11. #11
    Join Date
    Jan 2013
    Posts
    12
    I just looked at an online calculator and compared the price per BTU for my 80 percent eff oil furnace vs electric resistance heating and at the prices I'm paying they come out very close. Does this mean I could heat my house on electric baseboard heaters for the same cost as my oil furnace?
    I always thought resistance heating was the most expensive method to heat a house?

  12. #12
    Join Date
    Jan 2013
    Posts
    12
    Thanks again for all the replys. I made another post in this section on a different subject regarding my heat pump freezing up titled "heat pump iced up/ interesting problem hybrid problem w/oil burner"

    Over 120 have read it but no replys yet. If anyone has any thoughts I'd like to here them.

  13. #13
    Join Date
    Mar 2006
    Location
    The South
    Posts
    2,188
    Your BTUs on your fuel oil furnace will remain constant when compared to heat pump heat BTUs that drops as outside temp drops.

    And yes, electric resistance heat on a BTU basis is cheaper than oil heat by close to 10%. of course this varies with your cost of fuel oil. My fuel comparison calculator while close is to be used a guide only.

    Was the addition of the HP installation by a qualified and licensed HVAC dealer?

    IMO

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