Home is a 3800 sq ft 2 story colonial. NY Energy Start certified 5 star. Located in Upstate NY.
Furnace is a Goodman GMVC1155 with a 4 ton compressor and 5 ton SEER 13 A Coil.
Furnace High Speed heat taps set to 1823CFM, Low Speed 1313CFM, Single Stage Cooling = 1540CFM (about 380 per Ton). Picture of the second floor attached. Blue shows the furnace trunk line in the basement (not the second floor) and the furnace location.
I built my house in 2010, the only issue/complaint I have is my upstairs bedroom (Bedroom 2) for my 2yr old doesn't get enough airflow, its always the coldest room in winter and hottest in summer. Its well insulated, i even have pics of the build and i was present every day to confirm. Unfortunately I never noticed this issue because for the first 8yrs I had the supply turned off in this room with door closed since it was empty (she was not born).
What i have tried.
I have bought a manometer and a anemometer to make as much adjustments as I can with what i have to work with. I cannot increase my furnace high stage heat anymore. The static pressure is to high above 1900CFM. I have trimmed the furnace to the levels you see above based on how i have my ducts balanced. This has provided optimal comfort throughout the home during both seasons, high and low stage heat and AC. Besides, nothing i do seems to increase "Bedroom 2" more than 400cfm on my anemometer.
I have the house pretty well balanced now with dampers marked for summer and winter.
Help
I am looking for ideas on how to rectify this. I am not interested in adding space heaters or window AC units i really would like to correct the mistake the best i can without gutting walls or ceilings. If it were up to me i would move the supply to closer to the furnace before my stairs not after but i would have the same problems since there are more microlams that way. I would just be taking the supply before 2 other rooms (both of which are on first floor)
Additional info:
The duct to her room (Bedroom 2) is a 6" rigid duct. Unfortunately the way the duct is run requires 4 elbows just in the basement to drop below a double microlam. I believe this adds additional friction loss and the main reason i cannot push the airflow necessary to her room. I would like to see 500-550cfm. The duct was also taken at the last part of the center trunk right before it drops down to its smallest size. Unfortunately i cannot change the pickup location on the trunk line anymore since my basement is now finished. My only option i see without significant work is to do something about these basement elbows to try to remove some friction loss. Dont quote me on the accuracy of the anemometer. If the values are high then at least i can compare them as a basis to the other upstairs bedrooms of the same size supply and returns. They flow about 550CFM on my anemometer. They are comfortable.
I have tried closing down other ducts on the end of the trunk line just to observe the anemometer readings. Nothing i can do gets the flow above 400CFM. If i close to many of them (like 4+) my furnace will throw a B3 code only when in high stage heat due to the increased static pressure. I wouldn't really want this anyway since i would be shutting the supply from the other 2 kids bedrooms to zero.
Would a flexible duct like shown in the picture have reduced friction loss if i could form it to a longer sweeping bend and pulled it tight (installed correctly), or are the 4 tight radius elbows still better?
Furnace is a Goodman GMVC1155 with a 4 ton compressor and 5 ton SEER 13 A Coil.
Furnace High Speed heat taps set to 1823CFM, Low Speed 1313CFM, Single Stage Cooling = 1540CFM (about 380 per Ton). Picture of the second floor attached. Blue shows the furnace trunk line in the basement (not the second floor) and the furnace location.
I built my house in 2010, the only issue/complaint I have is my upstairs bedroom (Bedroom 2) for my 2yr old doesn't get enough airflow, its always the coldest room in winter and hottest in summer. Its well insulated, i even have pics of the build and i was present every day to confirm. Unfortunately I never noticed this issue because for the first 8yrs I had the supply turned off in this room with door closed since it was empty (she was not born).
What i have tried.
I have bought a manometer and a anemometer to make as much adjustments as I can with what i have to work with. I cannot increase my furnace high stage heat anymore. The static pressure is to high above 1900CFM. I have trimmed the furnace to the levels you see above based on how i have my ducts balanced. This has provided optimal comfort throughout the home during both seasons, high and low stage heat and AC. Besides, nothing i do seems to increase "Bedroom 2" more than 400cfm on my anemometer.
I have the house pretty well balanced now with dampers marked for summer and winter.
Help
I am looking for ideas on how to rectify this. I am not interested in adding space heaters or window AC units i really would like to correct the mistake the best i can without gutting walls or ceilings. If it were up to me i would move the supply to closer to the furnace before my stairs not after but i would have the same problems since there are more microlams that way. I would just be taking the supply before 2 other rooms (both of which are on first floor)
Additional info:
The duct to her room (Bedroom 2) is a 6" rigid duct. Unfortunately the way the duct is run requires 4 elbows just in the basement to drop below a double microlam. I believe this adds additional friction loss and the main reason i cannot push the airflow necessary to her room. I would like to see 500-550cfm. The duct was also taken at the last part of the center trunk right before it drops down to its smallest size. Unfortunately i cannot change the pickup location on the trunk line anymore since my basement is now finished. My only option i see without significant work is to do something about these basement elbows to try to remove some friction loss. Dont quote me on the accuracy of the anemometer. If the values are high then at least i can compare them as a basis to the other upstairs bedrooms of the same size supply and returns. They flow about 550CFM on my anemometer. They are comfortable.
I have tried closing down other ducts on the end of the trunk line just to observe the anemometer readings. Nothing i can do gets the flow above 400CFM. If i close to many of them (like 4+) my furnace will throw a B3 code only when in high stage heat due to the increased static pressure. I wouldn't really want this anyway since i would be shutting the supply from the other 2 kids bedrooms to zero.
Would a flexible duct like shown in the picture have reduced friction loss if i could form it to a longer sweeping bend and pulled it tight (installed correctly), or are the 4 tight radius elbows still better?
source https://hvac-talk.com/vbb/showthread.php?2223906-To-much-friction-loss-6-quot-duct&goto=newpost
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