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  1. #1
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    Feb 2017
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    Greenspeed 2 ton or 3 ton?

    I'm deciding to replace my baseboard electric heat with a new Greenspeed Infinity unit. After using Carrier's Greenspeed Calculator, I'm unsure about the size of the unit.

    I have a total of 1750 sq ft. I believe I need about 55,000 - 65,000 BTU's to heat my home since I'm in the northeast and temps get down to the teens. (which the Greenspeed should handle)

    So my doubt is that the 3 ton would be perfect for cooling and just right for my home, but when I run the Carrier calc.

    It show that the 3 ton is underpowered for heating, but the 4 ton is perfect.

    Now my questions...

    Does my home really need 55k - 65k btu heating?
    If I really need the 4 ton unit, would it be overkill and would improperly heat/cool my home?

    Please guide me. I'm lost!!
    Thank you in advance.

  2. #2
    Join Date
    Nov 2014
    Location
    Portland, Oregon, United States
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    Hire a competent company to perform a load calculation. That is the only way to find the answer to your question.

    Sent from my SM-G935T using Tapatalk

  3. Likes daveallen liked this post
  4. #3
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    Feb 2017
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    Thread Starter
    Thanks,

    This load calculation will tell me how much BTU's I need or which unit I need?

    All the contractors just ask me a sq footage of the place and thats all.

  5. #4
    Join Date
    Nov 2014
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    Portland, Oregon, United States
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    BTUs. Calculating by square footage is a rule of thumb strategy that really doesn't address things like solar gain, intended usage or loss and gain due insulation or construction methodology. These are the things you should discuss with your contractor.

    Sent from my SM-G935T using Tapatalk

  6. #5
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    Feb 2017
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    Thread Starter
    Reading the Greenspeed docs, I see the 3 ton hovers around 28k btu at a temp in the 20's. The 4 ton hovers around 50k btu at temps in the 20's.

    But I know the 4 ton is overkill for my home, it will heat and cool too fast. This would be lots of on/off for the unit and the temps would be fluctuating constantly.

    Anyone have a Greenspeed 3 ton or 4 ton unit? what sq footage is your home?

  7. #6
    Join Date
    Nov 2004
    Location
    SW FL
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    NO INFO Provided

    Quote Originally Posted by soundview View Post
    I'm deciding to replace my baseboard electric heat with a new Greenspeed Infinity unit. After using Carrier's Greenspeed Calculator, I'm unsure about the size of the unit.

    I have a total of 1750 sq ft.
    I believe I need about 55,000 - 65,000 BTU's to heat my home since I'm in the northeast and temps get down to the teens. (which the Greenspeed should handle)

    Does my home really need 55k - 65k btu heating?

    Please guide me. I'm lost!!
    Thank you in advance.
    35,000 [23,000 ] BTU/HR Heating [ Cooling ] would be my initial estimates for a residence < 30 years old.

    1. ZIP CODE
    2. AGE of residence
    ..... R-30 Ceiling, R-11 Walls?
    3, Number and type of windows
    4. 2 story ?
    /--------- 1,750 sq feet --- 39' x 23' perimeter ?
    /--------- < 9' ceilings

    5. Infiltration rate ?
    6. Current utility bills (USAGE) PER MONTH for ~ 24 months

    ATTACHMENT
    ----------- Generic
    ......... HVAC OP COST
    ... ... ... ... ... Example
    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

  8. #7
    Join Date
    Feb 2017
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    Thread Starter
    Hi dan sw fl,

    1. 06501 (New Haven)
    2. House built in 1978.
    Attic Blown in Cellulose 16" = R40
    Walls have fiberglass insulation, not sure how much.
    3. 16 total windows total. Double pane metal, but most of them have bad argon gas seals. So these windows need replacing.
    2 sets of sliding glass doors metal frames too.
    4. Raised ranch, ceilings are normal 8 foot. 1250 sq ft upstairs (9 windows, 1 patio glass door upstairs).
    Above ground basement on concrete slab, 550 sq ft of usable downstairs living room and a 2 car garage next to it.
    5. Not sure the infiltration rate. I think my home is decently sealed up. I had an energy audit and I passed the door fan test since they plugged up a bunch of seals in my home.
    6. Since I'm all electric, I have thermostats in every room. I have them in schedules too.

    Upstairs - 7:30am - 11:30pm = 72 degrees.
    Upstairs - 11:30pm - 7:30am = 60 degrees. (Besides the master bedroom which we close the door and keep it at 73 degrees)
    Downstairs - 7:30 - 11:30pm = 69 degrees
    Downstairs - 11:30pm - 7:30am = 58 degrees

    Remember this winter was mild....very mild.

    I'm at a .17 cents total supplier/delivery.

    Nov - Dec = 2,000 KW, $325 bill
    Dec - Jan = 3,397 KW, $475 bill
    Jan - Feb = 2,489 KW, $350 bill
    Feb - Mar = 2,434 KW, $345 bill

    So I would assume next year we can add 25%-50% to the above numbers....only if we have a cold winter.

    Looking at temp history over the last 5 years, I counted the number of days in Jan where the temps went under 16 degrees. It's between 7-14 days in Jan/Feb, temps will go into the teens. But mostly temps stay right around the freezing mark during the days and most nights.

    Thanks for asking details about my situation!!!! I have spent countless hours thinking and worrying about the proper new system to purchase.

  9. #8
    Join Date
    Feb 2017
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    Thread Starter
    What do you guys think?

  10. #9
    Join Date
    Jan 2008
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    2,931
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    Heat pumps are sized for the cooling load, not the heating load.
    "Hey Lama, hey, how about a little something, you know, for the effort." And he says, "there won't be any money, but when you die, on your deathbed, you will receive total consciousness." So I got that goin' for me, which is nice. - Carl Spackler

  11. #10
    Join Date
    Nov 2004
    Location
    SW FL
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    Electric use per month ?

    Quote Originally Posted by soundview View Post
    What do you guys think?
    IT is hard to discern
    HOW MUCH ELECTRICITY IS
    ACTUALLY USED FOR HEATING '
    without the APR-MAY & SPET -OCT $$$.

    What did the Audit indicate?

    A VERY Preliminary Estimate of the heating load at 15'F = 30,000 BTU/HR.

    The yearly bills should not fluctuate a large % based on more or less even Heating Degree Days.

    ATTACHMENT
    Attached Images Attached Images
    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. #11
    Join Date
    Feb 2017
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    Thread Starter
    Quote Originally Posted by dan sw fl View Post
    A VERY Preliminary Estimate of the heating load at 15'F = 30,000 BTU/HR.
    Thank you for the Audit. This is very interesting. Since this is the case and I need 30,000 btu's then I can get the 3 ton greenspeed unit.

    Also, did you take in account this is a much milder winter and my bills should have been between $550-$650 a month for Dec, Jan, Feb and March? Maybe I should add 5,000 btu's to the number?

    It pisses me off that this HVAC company said I need about 55,000 btu's to heat my home. Do you think they are trying to pull a fast one on me?

  13. #12
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
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    It is NOT a Much milder winter based on the Heating Degree Days summarized in the Attachment [provided previously ]. ~4% less than an 11 year average does not match my understanding of Much milder. /// Without adequate Facts, I don.t have a good basis for a judgment / conclusion. 4 months of electric bills is not sufficient to make a conclusion one can Act On.

  14. #13
    Join Date
    Feb 2017
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    Thread Starter
    I will dig up more electric bill from the last 2 years.

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