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  1. #14
    One more thing I realized while typing... I have an electric baseboard heater in the basement (finished) that I could use to add some BTUs on really cold days. Is there a way to wire this with the furnace so that it is controlled by the thermostat? Does this sound like a crazy one again?

    Thanks in advance,

  2. #15
    Join Date
    Dec 2010
    Location
    The Quad-Cities area (midwest).
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    2,476
    Quote Originally Posted by wally_walrus View Post
    One more thing I realized while typing... I have an electric baseboard heater in the basement (finished) that I could use to add some BTUs on really cold days. Is there a way to wire this with the furnace so that it is controlled by the thermostat? Does this sound like a crazy one again?

    Thanks in advance,
    I agree with Sky (King) Heating...............there are good reasons for having more (or enough in reserve). As S.K.H. said, some people like to set the heat back and want a quick recovery. Maybe you sell the home and some old fart moves in (like my father) that keeps the heat on 85 degrees.

    Having a seperate heat source would be a good idea if you're going to be "on the line." I undersized my furnace (long story) and have not told my wife. If we have a really cold winter, I'll have some explaining to do.

    But I'm not too worried because I have zoning.
    I'll just keep one area of the home (2nd floor bedrooms) colder than normal.

  3. #16
    Join Date
    Jun 2001
    Location
    Moore, Oklahoma, United States
    Posts
    3,944
    I'd go 45K single stage before 60k multistage. Anything you buy over 45k is a waste IMHO. If you have a United Refrigeration supplier in your area see if anybody installs thermalzone. Same as Rheem, but "house brand". It's what I have in my own home. Ruud is also the same as Rheem.

    Not sure if you need upflow or downflow, but here's the link for upflow.
    http://www.thermalzone.com/products/...es/TZ92UP.html

    Id leave the baseboard heaters as-is and turn on if needed. No sense in wiring into furnace. Also a nice backup if there is ever a furnace failure.
    Last edited by 54regcab; 12-07-2012 at 08:03 AM.

  4. #17
    Join Date
    Jan 2009
    Location
    Keokuk, IA
    Posts
    5,520
    Quote Originally Posted by George2 View Post
    Having a seperate heat source would be a good idea if you're going to be "on the line." I undersized my furnace (long story) and have not told my wife. If we have a really cold winter, I'll have some explaining to do.

    But I'm not too worried because I have zoning.
    I'll just keep one area of the home (2nd floor bedrooms) colder than normal.
    How much did you undersize by vs. Manual J? Just curious. I've been tempted to undersize/marginally size my furnace and downstairs AC. My Gas bills support that I don't need more than 65k total in my home and that includes heating a unfinished basement. Worst case, I can close off some basement registers in really cold weather. IF I got 45k BTU 2 stage and dual fuel 2 ton heat pump, I could have a system that runs pretty much continously under about a 50F outdoor temp. The second point beign that a 2 stage furnace is more efficient in 2nd stage, so a smaller unit increases 2nd stage run time.

  5. #18
    Join Date
    Dec 2010
    Location
    The Quad-Cities area (midwest).
    Posts
    2,476
    Quote Originally Posted by motoguy128 View Post
    How much did you undersize by vs. Manual J? Just curious. I've been tempted to undersize/marginally size my furnace and downstairs AC. My Gas bills support that I don't need more than 65k total in my home and that includes heating a unfinished basement. Worst case, I can close off some basement registers in really cold weather. IF I got 45k BTU 2 stage and dual fuel 2 ton heat pump, I could have a system that runs pretty much continously under about a 50F outdoor temp. The second point beign that a 2 stage furnace is more efficient in 2nd stage, so a smaller unit increases 2nd stage run time.
    I'm embarressed to say that I did not do a manual J. Just seat of my pants based off my old furnaces' operation.

    I've been in the home 35 yrs. I had (as I remember) a 83,000 Btu output Bryant (Plus 90i) in my home. One very cold winter, it would run almost non stop. In fact, the blower never had time to cycle. The burner would drop out for 5 seconds and then re-fire. Perfect.

    So the new furnace is a Bryant 95% (2-stage) with 76,000 Btu output. So it should be plenty 99% of the time. Almost 10% less output.

  6. #19
    So what does everyone think of a slightly undersized two stage 40K input 39K output? Is there a way to interlock an additional heater (electric perhaps) to the furnace so that it adds a couple K BTU on the coldest day? Or the only solution is manually turning an electric heater ON? I'm trying to stay with the contractor that seems the most competent, but even he (the salesman) is hesitant going with 40K

    Like mentioned I could also reduce the ventilation, as well as will replace the water heater with a High Eff. direct vented model and will be able to close off two more holes in the envelope (make up supply air and chimney)

    Unfortunately we don't have a lot of choices when it comes to contractors up here, most customers are government employees clueless and with large pockets

    Thanks in advance,

  7. #20
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    5,985
    Quote Originally Posted by wally_walrus View Post
    So what does everyone think of a slightly undersized two stage 40K input 39K output?

    Is there a way to interlock an additional heater (electric perhaps) to the furnace so that it adds a couple K BTU on the coldest day?
    Or the only solution is manually turning an electric heater ON?

    Thanks in advance,
    There are _Always at least a dozen ways_ to solve an HVAC issue.

    "... ADD a couple k BTU " ... 1500 Watts * 3.413 = 5,120 BTU.

    K EEP I T S IMPLE & S INCERE
    _______ KISS ______________

    You could "interlock this temperature controlled room heater with a cold body" and it would operate
    when it's colder than design temperature (~ 175 hours per year, < 2% ASHRAE design temperature = .02 * 24 * 365 = 8760/50 = 175 hours ).
    + In reality, You might be talking about 28 nights from 2 am to 8 am when you are under the blanket with the room temperature dropping < 4'F / 5%.

    Set room temperature to 68'F and small heater to 65' - 66'F or similar.
    http://www.amazon.com/Vornado-Vortex.../dp/B00063ZVK0
    __ 3 heat settings __

    Vornado DVTH Portable Whole Room Vortex Heater Model # EH1-0028-06
    Home Depot Internet # 202364079

    IT'S ART SOMETIMES, NOT ALL SCIENCE.!
    That way one does not get into "paralysis by analysis" / overthinking.

    1500 Watts at 175 hours = 263 kW or $ 26 to operate per year.

    Or if you really in a bind for $$$, $24 for a heater, Target.
    Holmes Products HCH4062B-UM Ceramic Heater

    ____ There are _Always at least a dozen ways_ to solve an HVAC issue ___
    depending on climates, comfort levels, budgets, personalities, and preferences.
    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. #21
    Join Date
    Jun 2001
    Location
    Moore, Oklahoma, United States
    Posts
    3,944
    IMHO you won't even need the room heater, I think man J has enough fudge factor built in to cover the colder than design temperature nights.

  9. #22
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
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    Quote Originally Posted by 54regcab View Post
    IMHO you won't even need the room heater, I think man J has enough fudge factor built in to cover the colder than design temperature nights.
    _ Just to provide some information for myself on small heater sizing -
    _ Experiment-of-sorts

    750 / 1,500 Watts [2,560 /5,120 BTU/hr] ceramic heater works well at maintaining an even 70'F temperature for ALL the heating required in a 900 square foot rented Upstate SC condo for > 54'F/ 43'F outside air. _____________

    The number of hours at < 40'F is Not large / rarely < 27'F recent winter.

    The heat pump is HUGELY OVERsized at 2.5 tons.
    ______________ Hugely = probably close to 1.5 times at ~20'F.
    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. #23
    Quote Originally Posted by wally_walrus View Post
    So what does everyone think of a slightly undersized two stage 40K input 39K output? Is there a way to interlock an additional heater (electric perhaps) to the furnace so that it adds a couple K BTU on the coldest day? Or the only solution is manually turning an electric heater ON? I'm trying to stay with the contractor that seems the most competent, but even he (the salesman) is hesitant going with 40K

    Like mentioned I could also reduce the ventilation, as well as will replace the water heater with a High Eff. direct vented model and will be able to close off two more holes in the envelope (make up supply air and chimney)

    Unfortunately we don't have a lot of choices when it comes to contractors up here, most customers are government employees clueless and with large pockets

    Thanks in advance,

    Sorry, I'm at it again... Here are the numbers:

    Component Btuh/ft² Btuh % of load
    Walls 1.3 8927 20.9
    Glazing 30.6 5941 13.9
    Doors 9.4 548 1.3
    Ceilings 2.5 2158 5.1
    Floors 5.5 4694 11.0
    Infiltration 37.1 9391 22.0
    Ducts 0 0
    Hydronic 0 0
    Humidification 0 0
    Ventilation 11016 25.8
    Adjustments 0
    Total 42674 100.0

    So what does everyone think of a slightly undersized two stage 40K input 39K output, given ventilation won't ever reach 120CFM and HRV efficiency is ~50%?

    Is this reason to put a disclaimer in the contract that warranty might be affected? I'd like to purchase an extended warranty

  11. #24
    Join Date
    Jun 2001
    Location
    Moore, Oklahoma, United States
    Posts
    3,944
    If it's colder than design conditions could you just run off the HVR temporarily? When it's that cold stack effect should bring in enough fresh air.

  12. #25
    Quote Originally Posted by 54regcab View Post
    If it's colder than design conditions could you just run off the HVR temporarily? When it's that cold stack effect should bring in enough fresh air.
    Sure can, using my VisionPro IAQ Ventilation menu

  13. #26
    Join Date
    Jun 2001
    Location
    Moore, Oklahoma, United States
    Posts
    3,944
    Quote Originally Posted by wally_walrus View Post
    Sure can, using my VisionPro IAQ Ventilation menu
    Can it be set to automatically do so below a certain outdoor temperature?

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