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  1. #1
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    Dec 2012
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    Calculating savings between heating/cooling systems

    I currently have an old Evco/Coleman HP and Furnace---about 20 years old. I'm thinking about replacing it with a new split/dual system: Heat pump (seer 16) and either a 80% or 96% gas furnace. Does anyone know of a website or spreadsheet that I can input my current utility costs (gas rate/electric rate) and then get an idea of the difference between the various efficiencies ?

    I don't need exact figures, just something like: "If I'm paying a hundred bucks now, how my less with ...........this or that model and rating."


    Another thing I'm wondering about is how much more efficient in terms of electric use are the new H.P.'s and furnaces compared to my 20 year old stuff.

  2. #2
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  3. #3
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    Excellent. Thanks.

  4. #4
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    keep in mind a HUGE improvement in efficiency and comfort will be gained if you have any ductwork in unconditioned space especially an attic!
    old ductwork practices didn't cover properly or with enough insulation. also, seams and joints add up to major duct leakage and change the pressures on your home. fixing this stuff makes as much or more difference in your heating/cooling bills as new high efficiency equipment!
    The TRUE highest cost system is the system not installed properly...
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  5. #5
    Join Date
    Dec 2012
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    62
    Yes, point taken.

    I'll admit, I must be a complete idiot.

    When I tried to use the web link (above) to run some comparisons on HVAC equipment and conditions-----the results made no sense. Even the heating/cooling days and hours don't make sense. How can a milder climate like Portland, OR compare to all the other colder climate areas ?

    That aside, I'm just trying to come up with a rough idea of savings based on this:

    Current system
    Natural gas furnace: Coleman/Evco 100,000 BTU @ 80%, single stage/fixed speed
    Heat Pump: Coleman/Evco 3.5 ton (who knows the SEER or HSPF rating)

    Proposed System
    Natural Gas Furnace: 60,000--70,000 BTU @ 95%, dual stage/variable speed
    Heat Pump: 16.0 SEER, 9.0 HSPF

    FYI: This would be in a 2800 sq/ft well insulated, well ducted house. Those figures are just for comparison.
    Gas Rate: $1.18/therm and around 6 cents per kWh. Last year the current gas furnace burnt up around 428 therms @$500 for the months (November-May) that I needed gas heat. Otherwise it was the heat pump for heat and cooling for the rest. Total yearly electrical usage was around 8,000 kwh including all electrical usage.

    The other thing that baffles me is would a variable fan/2 stage furnace that runs longer cost more to operate than my full heat/no heat old tank furnace----especially in terms of electricity usage ? Same with the heat pump running longer, but more efficient.

    What I'm looking for is this: For every $100 I spend in both electricty and gas now, how much can I expect to save with the newer gear ???? Based on everthing else the same (fuel rate, ducts, insulation....etc)

    Thanks everyone. This is a great community website




    Quote Originally Posted by vstech View Post
    keep in mind a HUGE improvement in efficiency and comfort will be gained if you have any ductwork in unconditioned space especially an attic!
    old ductwork practices didn't cover properly or with enough insulation. also, seams and joints add up to major duct leakage and change the pressures on your home. fixing this stuff makes as much or more difference in your heating/cooling bills as new high efficiency equipment!

  6. #6
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    Post model number of the heat pump. One of us may be able to tell you the SEER/HSPF.
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  7. #7
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    Dec 2012
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    Heat Pump #

    Looks like ODHSO42B (O's may be 0 and the S may be a 5) and I believe it has a 1/4 HP motor. Evcon/Coleman DHS 042B ??


    Quote Originally Posted by beenthere View Post
    Post model number of the heat pump. One of us may be able to tell you the SEER/HSPF.

  8. #8
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    That one I don't recognize.
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  9. #9
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    Quote Originally Posted by mixer440 View Post
    When I tried to use the web link (above) to run some comparisons on HVAC equipment and conditions-----the results made no sense.
    Even the heating/cooling days and hours don't make sense.
    How can a milder climate like Portland, OR compare to all the other colder climate areas ?

    rough idea of savings based on this:
    Coleman/Evco 100,000 BTU @ 80%, single stage/fixed speed
    Coleman/Evco 3.5 ton (who knows the SEER or HSPF rating)

    Proposed System
    Natural Gas Furnace: 60,000--70,000 BTU @ 95%, dual stage/variable speed
    Heat Pump: 16.0 SEER, 9.0 HSPF

    FYI: This would be in a 2800 sq/ft well insulated, well ducted house. Those figures are just for comparison.
    Gas Rate: $1.18/therm and around 6 cents per kWh.
    Last year the current gas furnace burnt up around 428 therms @$500 for the months (November-May) that I needed gas heat.
    Otherwise it was the heat pump for heat and cooling for the rest. Total yearly electrical usage was around 8,000 kwh including all electrical usage.

    The other thing that baffles me is would a variable fan/2 stage furnace that runs longer cost more to operate than my
    full heat/no heat old tank furnace----especially in terms of electricity usage ?
    Same with the heat pump running longer, but more efficient.

    For every $100 I spend in both electricity and gas now, how much can I expect to save with the newer gear ????
    Based on everything else the same (fuel rate, ducts, insulation....etc)
    8,000 KW-HR ANNUAL for 2,800 Square Feet residence in OR seems VERY LOW.

    Portland OR has ~5,000 Heating Degree Days due to 7+ months heating season

    http://www.climate-zone.com/climate/.../oregon/salem/

    Guessing
    40,000 BTU/Hr might be
    950 therms total annual for heating.
    400 therms gas ... savings from use of 95% instead of 80% might be $80 per year

    Remaining electric
    550 therms/ 55,000,000 BTU annual should be close to 2,000 operating hours

    6,000 kW for heat pump is only $360 / year { actually I would expect MORE usage of heat pump}
    20% savings at best ( HSPF NEW 9 versus ~ 7.2 OLD) is < $100 per year.

    Spending only $860 per year currently means you're doing a lot of right things Now.
    I don't see how you can get annual heating bill < $700.

    Discuss with Travis at skyheating dot com for local advise.
    http://www.youtube.com/watch?v=G6_8Jc5DPQw
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

  10. #10
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    How do you do a heat pump on that link? and it's last update is 2008.......
    Always here

  11. #11
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    Quote Originally Posted by energy star View Post
    How do you do a heat pump on that link? and it's last update is 2008.......
    Use something similar to_:
    ____ HSPF COP
    ____ ____ 3.41 ( 1/0.293)



    ____ 10.2 2.99
    ____ 10.0 2.93
    2014 9.8 2.87
    2012 9.6 2.82
    2010 9.4 2.76
    2008 9.2 2.70
    2006 9.0 2.64
    2004 8.8 2.58
    2002 8.6 2.52
    2000 8.4 2.46
    1998 8.2 2.40
    1996 8.0 2.35
    1994 7.8 2.29
    1992 7.6 2.23
    1990 7.4 2.17
    1988 7.2 2.11

    http://en.wikipedia.org/wiki/HSPF


    Of course , a heat pump operating at >~ 35'F the COP can be >> 2.99 (HSPF 10.2).
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

  12. #12
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    Yeah....But...hvacopcost link is not what the op was looking for. I beleive that site (That link) is just for ac and gas furnaces.
    Always here

  13. #13
    Join Date
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    Location
    SW FL
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    Quote Originally Posted by energy star View Post
    Yeah....But...hvacopcost link is not what the op was looking for. I beleive that site (That link) is just for ac and gas furnaces.
    HeatPump is selected under Heating in the right side column.
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

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