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  1. #1

    Trane Comfortlink II w/ 95% furnace - bad airflow to far side of house

    I could use some advice on the best way to increase airflow to the far side of the house. My furnace is all the way on one side of the house in the basement and the 2 bedrooms on the opposite side of the house on the 2nd floor are always hot in summer/cold in winter. The hot summer issue isn't a huge deal since we've gotten new windows and installed ceiling fans in those rooms, but I'm having a hard time keeping them as warm as the rest of the house in winter. I'm sure it doesn't help that they are above an uninsulated garage and the ducts all come from an unfinished basement with minimal insulation. It's probably also worth mentioning I live @ roughly 6000 feet and humidity is very low.

    With our old furnace that always ran @ 100% the problem wasn't as bad. With this new multi stage system it seems when the furnace is just cycling on to its lowest stage that there is barely any air coming out of the vents in those 2 rooms and the air coming out in those rooms barely even gets warm. I've put together a list of options that seem to me will help the situation and wanted some professional opinions on whats the best way to proceed.

    1 - If possible, can I eliminate the lowest stage of the furnace? So even on its lowest setting the fan will push more volume of air?

    2 - Fans - Are those inline fans that go into the duct worth installing? I've identified which 2 ducts feed those 2 rooms from the basement. They are easily accessible. Will I have issues with those fans turning on and off via the furnace control in one of these variable speed setups? Probably need some kind of relay in there?
    2b - If I finish the basement and one of those fans were to go bad, it would be a huge pain to get to them. Are they fairly reliable?
    2c - Are those cheap fans that go on top of the register worth checking out as an alternative?

    3 - For one of the bedrooms in question it would be pretty easy to get a return line into, on the down side it would be in the closet. Is it worth putting a small return in the closet?

    4 - Should I wrap the ducts in the basement with insulation?

    5 - The garage beneath these rooms has no insulation on the outside walls or the doors. There is at least insulation between the bedroom floor/garage ceiling. How much will I gain by insulating the garage?

    6 - I've closed several vents on the main floor of the house in hopes of getting some more flow upstairs but it doesn't seem like it helped. Am I causing more harm than good by doing this?

    Sorry to puke so many questions on my 1st post here, but I'm at a loss for what to do next. I've got what I believe is a high end furnace and very good new windows but my kids are still freezing @ night. Any insight is greatly appreciated!

  2. #2
    Join Date
    Nov 2004
    Location
    SW FL
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    6,440
    You may wish to review Vornado products as a simple fix.

    http://www.vornado.com/heaters/AVH2-Heater
    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

  3. #3
    Few problems with the space heater solution is that they obviously take up space in a kids bedroom and with kids crap everywhere I worry about fire danger. While on high that's another 26 amps of power being drawn on a 20 amp circuit that feeds those rooms. They also dry out the air pretty badly and low humidity is a problem to begin with. I have a whole house humidifier on the furnace that I would like the air to cycle through. I see you're from SW Florida - I also lived in SW Florida for a while and I can most certainly say the winters here in Colorado are a huge contrast to yours. Extreme low humidity is a problem you don't have down there... and when's the last time Ft Myers had sub zero temps

    Those do seem like the big daddy of all space heaters though.

  4. #4
    Join Date
    Jul 2006
    Location
    Virginia
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    4,905
    you need to have the duct work fixed ,more than likely they are to small a return won't fix it
    We really need change now

  5. #5
    Join Date
    Nov 2004
    Location
    SW FL
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    6,440
    Quote Originally Posted by insanity213 View Post

    Few problems with the space heater solution is that they obviously take up space in a kids bedroom and with kids crap everywhere I worry about fire danger. While on high that's another 26 amps of power being drawn on a 20 amp circuit that feeds those rooms. They also dry out the air pretty badly and low humidity is a problem to begin with. I have a whole house humidifier on the furnace that I would like the air to cycle through.

    I see you're from SW Florida - I also lived in SW Florida for a while and I can most certainly say the winters here in Colorado are a huge contrast to yours.
    Extreme low humidity is a problem you don't have down there... and when's the last time Ft Myers had sub zero temps

    Those do seem like the big daddy of all space heaters though.
    Hopefully where one currently lives does not prevent one from understanding all the ranges of the psychometric chart.

    People live in many places during their lives.
    The last time I had the opportunity to experience sub-zero, I was out barbequeing.

    One should be able to adapt to either -20'F to 120'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

  6. #6
    Quote Originally Posted by dan sw fl View Post
    Hopefully where one currently lives does not prevent one from understanding all the ranges of the psychometric chart.

    People live in many places during their lives.
    The last time I had the opportunity to experience sub-zero, I was out barbequeing.

    One should be able to adapt to either -20'F to 120'F.
    Sure, grown men like ourselves can adapt very easily. I've bbq'ed in low temps - in fact that's when I prefer to do my cold smoking. That has absolutely nothing to do with this conversation. "Adapting" isn't an option for a sick kid who gets rushed to the ER when her airway closes due to single digit relative humidity. I wanted some ideas on how to make my system perform better and you seemingly don't have an answer. I thank you for your time but I think I'll go with the advice of having larger ductwork installed for those rooms.

    Sent from my Nexus 7 using Tapatalk 2

  7. #7
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,440
    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. #8
    Join Date
    Dec 2011
    Location
    San Antonio, TX
    Posts
    381
    Might be worth getting an air balance performed on your home. Also test your duct for leakage. And yes, insulate your ducts.

  9. #9
    Join Date
    Jun 2005
    Location
    SW Wisconsin
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    5,035
    I believe as stated in another post; I'd have dampers installed at all the take-offs for balancing.

    Then for those runs going to the far bedrooms, if there is room use a large main rectangle run coming off the plenum, reduce its size once at 18 to 24 feet (?) or so, to increase static pressure & velocity to the outlet supply air diffusers.

    The boot to the diffuser is also critical as to design efficiency, as are the diffusers toward improving the bedroom airflow.

    If coming off a main rectangular run, then use an extra large tapered take-off collar to a large duct that reduces to the size going up the walls; this provides the larger take-off area from the plenum & the large main run for increased air volume to the bedroom ducts.

    I would definitely consider insulating the bedrooms from the garage area & the ducts in any cold area.

    Also, figure out the best way to have more than adequate Return Air from those bedrooms. Hopefully, that will allow you to again operate the furnace on the low fire low airflow first stage, as the airflow would be better balanced enabled...

    You could also use an automatic adjustable Zone Damper balancing system on that new duct design; that could be set to auto-balance in both high & low airflow stages...

    Insure that the Return Air Filter area is large enough & that you use low back-pressure fiber glass media type filters.

    The better the Return Air functions the more apt the system will be enabled to deliver sufficient volumes of warm air to those distant bedrooms.

    You can click on my image above & go to my other posts & my website on Optimal Sizing of Return Air Filter Areas.

  10. #10
    Join Date
    Jul 2008
    Location
    Rochester NY
    Posts
    4,763
    Your house is always LOSING heat, whether the equipment is on or not.

    Your house only heats when the equipment is on, and btu delivered to each space depends upon not only airflow to each space, but how long the equipment is ON.

    Duct has to warm up before warm air goes to the rooms (If you need to see this, check out charts from my Ecobee thermostats. The higher addresses are upstairs units. The furnaces in my South Plymouth house are GROSSLY oversized. Imagine what would be delivered upstairs if they cycle times were based upon the downstairs cycle time.)

    If it's not on long, you may get little to no heat in the furthest rooms because all the heat is absorbed into the cold duct.

    With bad design you can throw more energy at the problem and still be uncomfortable. We call that the old "poke n hope".

    With good design you can cut your energy cost and IMPROVE your comfort. Are you willing to make a little investment in design? You need to design in such a way that loss matches replacement. And the more evenly you design to do this typically the more comfortable and efficiently it occurs.

    Are energy audits available where you live?
    Which makes more sense to you?
    CONSERVATION - turning your thermostat back and being uncomfortable. Maybe saving 5-10%
    ENERGY EFFICIENCY - leaving your thermostat where everyone is comfortable. Saving 30-70%

    DO THE NUMBERS! Step on a HOMESCALE.
    What is comfort? Well, it AIN'T just TEMPERATURE!

    Energy Obese? An audit is the next step - go to BPI.org, or RESNET, and find an auditor near you.

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