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Thread: 60K BTU vs 80

  1. #1
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    Confused 60K BTU vs 80

    Hello, I am currently replacing a 22 year old Bryant HVAC system. I am looking at Amana and have had 3 companies give me quotes. I am choosing between two.
    I live near Camp Hill, PA., southern side. Checking the climate zone maps I am border line between zone 3 and 4. The current system is 2 1/2 ton AC with an 80K BTU 90% furnace single stage. Contractor #1 originally chose a 2 ton 16 seer w/h 60K BTU 96% 2 stage furnace. Then bumped it up to a 2 1/2 ton (ASK series) with an 80K BTU 2 stage (AMEC series) supposedly because there was a change in something from manufacturer.
    Contractor #2 chose the exact same 2 1/2 ton AC unit but has me at a 60K 96% furnace (AMVC series).

    My house is 22 years old, built on a slab, not air tight, large windows (some recently replaced) facing southwest and 1309 square ft. Since these are 2 stage furnaces, I am wondering with the 80K, if it will ever go into high fire to justify the cost increase. Then again, I wonder if the 60K would be sufficient.

    No one has done a load calculation. I tried without success.

    Any advice and opinions welcome.
    Thank you.

  2. #2
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    If your furnace cycles off at all on the coldest days of the year then you can go smaller.
    And smaller is pretty much always better for comfort.
    You don't squat with your spurs on.
    And you NEVER put the torches away before pressure testing.

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  4. #3
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    HVAC DESIGN PROCESS

    Quote Originally Posted by Kate0124 View Post
    Hello, I am currently replacing a 22 year old Bryant HVAC system. I am looking at Amana and have had 3 companies give me quotes. I am choosing between two.

    I live near Camp Hill, PA., southern side.

    Checking the climate zone maps I am border line between zone 3 and 4.

    The current system is 2 1/2 ton AC with an 80K BTU 90% furnace single stage.

    Contractor #1 originally chose a 2 ton 16 seer
    w/h 60K BTU 96% 2 stage furnace.


    Then bumped it up to a 2 1/2 ton (ASK series) with an 80K BTU 2 stage (AMEC series) supposedly because there was a change in something from manufacturer.

    Contractor #2 chose the exact same 2 1/2 ton AC unit
    but has me at a 60K 96% furnace (AMVC series).

    My house is 22 years old, built on a slab, not air tight,
    large windows (some recently replaced)
    facing southwest and 1309 square ft.

    Since these are 2 stage furnaces, I am wondering with the 80K, if it will ever go into high fire
    to justify the cost increase. Then again, I wonder if the 60K would be sufficient.

    No one has done a load calculation.
    I tried without success.

    Any advice and opinions welcome.
    Thank you.
    Heat Loss at 15'F is likely < 32,000 BTU/HR

    Built 1999 -- 1,309 Sq Feet


    I would likely recommend a 2-stage furnace / heat pump ( Hybrid System).
    i.e. Bryant, TRANE or equal

    Heat loss calculation will need to be performed to verify that
    40,000 BTU/HR furnace is adequate.

    MONTHLY Natural Gas USE [ Therms ] over the last 12 to 24months
    can be used to check the Manual J calculation.


    Window Schedule is required.
    ___ WWW.MYSIMPLIFIEDHVAC.COM
    Attached Images Attached Images   
    Designer Dan __ It's Not Rocket Science, But It is SCIENCE with Some Art. _ _ KEEP IT SIMPLE & SINCERE ___ __ www.mysimplifiedhvac.com ___ __ Define the Building Envelope & Perform a Detailed Load Calc: It's ALL About Windows & Make-up Air Requirements. Know Your Equipment Capabilities

  5. #4
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    Ask for the AHRI number to prove they install a matching system, at up to 16 SEERS your state or local utility company company probably has rebates along with the furnace energy efficiency level.

    You have any issues with your ductwork in regards to hot/cold spots, ( wide temperature swings ) needing modifications, sealing, noisy, sized correctly now would be the time to discuss with bidding Contractors.

    Have you tightened up the home since you added the existing equipment, ( if you had it installed 22 years ago ) or do you know what was done to the residence if you are not the original owner of the equipment as you may get by with smaller capacity equipment?

    There is also the Federal Tax Credits for both the A/C and furnace.

    Register your system, as if going with the Amana, you will miss out on their outstanding manufacturers warranty if never registered. Everything needs to be registered, coil furnace and outdoor unit on whichever brand you decide on.

    Ask for a start up/ commissioning report upfront as they may need to adjust the bid price a tad to take into consideration the time to do a somewhat detailed report ( report should be left at job site ) things like static pressures, final field refrigerant charge, temperature rise across HX, amprege draws of motors and compressor, CFM adjustment, having correct ductwork etc.etc. They are putting pieces together and hopefully fine tune your system to manufacturers specifications. Some companies do a better job than others at that.

    Never heard of a 2 1/2 ton (ASK series ) a ASX series yes..

    AMEC furnace is a multi speed ECM blower motor whereas the AMVC is the variable speed blower motor. Both look to be communicating.

    https://www.energystar.gov/about/fed...ty_tax_credits

    You can try this free load calculation if you haven’t tried it already

    https://www.google.com/url?sa=t&rct=...wxqi0c65CNPb1r

    Possible one source for rebates:

    https://www.google.com/url?sa=t&rct=...iQc0GVu13UMfK_

    Thinking you should be getting at the minimum a one year labor warranty.

    Reusing existing lineset? if so is it sized correctly for the new equipment?

    Believe they make furnaces in 70K input capacity also.
    Last edited by Bazooka Joe; 05-11-2021 at 02:36 PM.

  6. #5
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    MANUAL J CALC _ SAMPLE

    TYPICAL Calc

    I DO NOT KNOW
    1. Perimeter of the house
    2. Number, size, type and orientation of the windows.
    3. R-30 Ceiling
    4. R-13 Walls

    14'F Winter __ 34,340 BTU/HR
    Attached Images Attached Images   
    Designer Dan __ It's Not Rocket Science, But It is SCIENCE with Some Art. _ _ KEEP IT SIMPLE & SINCERE ___ __ www.mysimplifiedhvac.com ___ __ Define the Building Envelope & Perform a Detailed Load Calc: It's ALL About Windows & Make-up Air Requirements. Know Your Equipment Capabilities

  7. #6
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    Thread Starter
    [QUOTE=dan sw fl;26044187] TYPICAL Calc

    I DO NOT KNOW
    1. Perimeter of the house
    2. Number, size, type and orientation of the windows.
    3. R-30 Ceiling
    4. R-13 Walls

    @ dan sw fl

    I have only owned this house for <2 years. I do not know anything about the insulation other than there is lots of it (loose) in the rafters / attic. The current system is in the garage and is quiet. I have found the heat to be uneven. Noticed in the summer you will feel warm air out of the ducts for a few seconds before the cool air. Can't speak if that happens in reverse.
    Perimeter of the house comes in at 352 sq ft by my measurements using a metal tape measure.

    I have 9 vinyl, double pane, double hung windows. All are original with the noted exception.

    (6) 35" W x 70" L facing SW (4 are brand new)
    (1) 24" W x 36" L facing N/NW
    (1) 48" W x 70" L facing NE
    (1) 24" W x 36" L facing SE

    36" x 80 Steel door w/h storm facing NE
    32" x 80 Steel door full glass w/h storm facing SE
    32" x 80 Steel door to unheated garage

    1 fireplace

    All ceilings height are 8 ft with the exception of about 300 sq ft which is 10 ft.

    I tried to do the load calculation using the form you are using but got lost. I appreciate all the information and help.

  8. #7
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    [QUOTE=Kate0124;26044777]
    Quote Originally Posted by dan sw fl View Post
    TYPICAL Calc

    I DO NOT KNOW
    1. Perimeter of the house
    2. Number, size, type and orientation of the windows.
    3. R-30 Ceiling
    4. R-13 Walls

    @ dan sw fl

    I have only owned this house for <2 years. I do not know anything about the insulation other than there is lots of it (loose) in the rafters / attic. The current system is in the garage and is quiet. I have found the heat to be uneven. Noticed in the summer you will feel warm air out of the ducts for a few seconds before the cool air. Can't speak if that happens in reverse.
    Perimeter of the house comes in at 150 Linear Feet [ ?? 352 sq ft ] by my measurements using a metal tape measure.

    I have 9 vinyl, double pane, double hung windows. All are original with the noted exception.

    (6) 35" W x 70" L facing SW (4 are brand new)
    (1) 24" W x 36" L facing N/NW
    (1) 48" W x 70" L facing NE
    (1) 24" W x 36" L facing SE

    36" x 80 Steel door w/h storm facing NE
    32" x 80 Steel door full glass w/h storm facing SE
    32" x 80 Steel door to unheated garage

    1 fireplace

    All ceilings height are 8 ft with the exception of about 300 sq ft which is 10 ft.

    I tried to do the load calculation using the form you are using but got lost.
    I appreciate all the information and help.
    Window Area: 156 Square Feet
    Double Pane

    Wall Area: ~ 1,360 Square Feet

    30,020 BTU/ HR at 13'F
    Attached Images Attached Images   
    Designer Dan __ It's Not Rocket Science, But It is SCIENCE with Some Art. _ _ KEEP IT SIMPLE & SINCERE ___ __ www.mysimplifiedhvac.com ___ __ Define the Building Envelope & Perform a Detailed Load Calc: It's ALL About Windows & Make-up Air Requirements. Know Your Equipment Capabilities

  9. #8
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    Camp Hill ? I've been there.

    1300 square feet. Even from way over here I am pretty sure I can see a 40K BTU furnace in your best future. <g>

    And it should probably be partnered with a 1.5 ton AC system

    You can do the heat loss/gain calculations yourself online if the slackers you have around there now won't (or don't know how to do) do them for you. And that really IS the starting point of answering your questions correctly.

    PHM
    ---------





    Quote Originally Posted by Kate0124 View Post
    Hello, I am currently replacing a 22 year old Bryant HVAC system. I am looking at Amana and have had 3 companies give me quotes. I am choosing between two.
    I live near Camp Hill, PA., southern side. Checking the climate zone maps I am border line between zone 3 and 4. The current system is 2 1/2 ton AC with an 80K BTU 90% furnace single stage. Contractor #1 originally chose a 2 ton 16 seer w/h 60K BTU 96% 2 stage furnace. Then bumped it up to a 2 1/2 ton (ASK series) with an 80K BTU 2 stage (AMEC series) supposedly because there was a change in something from manufacturer.
    Contractor #2 chose the exact same 2 1/2 ton AC unit but has me at a 60K 96% furnace (AMVC series).

    My house is 22 years old, built on a slab, not air tight, large windows (some recently replaced) facing southwest and 1309 square ft. Since these are 2 stage furnaces, I am wondering with the 80K, if it will ever go into high fire to justify the cost increase. Then again, I wonder if the 60K would be sufficient.

    No one has done a load calculation. I tried without success.

    Any advice and opinions welcome.
    Thank you.
    PHM
    --------
    The conventional view serves to protect us from the painful job of Thinking

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  11. #9
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    And just that quick - there you go Kate. <g>

    PHM
    --------




    Quote Originally Posted by dan sw fl View Post
    Heat Loss at 15'F is likely < 32,000 BTU/HR

    Built 1999 -- 1,309 Sq Feet


    I would likely recommend a 2-stage furnace / heat pump ( Hybrid System).
    i.e. Bryant, TRANE or equal

    Heat loss calculation will need to be performed to verify that
    40,000 BTU/HR furnace is adequate.

    MONTHLY Natural Gas USE [ Therms ] over the last 12 to 24months
    can be used to check the Manual J calculation.


    Window Schedule is required.
    ___ WWW.MYSIMPLIFIEDHVAC.COM
    PHM
    --------
    The conventional view serves to protect us from the painful job of Thinking

  12. #10
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    Thread Starter
    @ dan sw fl
    352 sq ft . That was a typo. Just 352 ft. Thanks for all the information. Greatly appreciated.

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