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Help: One Room colder than other rooms on the 2nd Floor

  • Last Updated:
  • Jan 12th, 2020 8:04 pm
[OP]
Jr. Member
Sep 10, 2006
119 posts
38 upvotes
Toronto

Help: One Room colder than other rooms on the 2nd Floor

Hi RFDers, we just moved into a 2-yr old house this July.
We realized that one room on the 2nd floor is much hotter than other rooms in the summer and much colder in the winter.
Initially, I thought it is due to poor insulation of our garage ceiling, but then I realized this room is NOT above our garage.
Also checked the duct registers and found the air is much colder than other rooms (when the furnace is on).
Any ideas why the air is much colder than others? And any advice on how to solve this issue? I am suspecting when the hot air goes through the duct above the garage, it gets cooled down because the garage is cold? But the room above the garage seems fine so I am confused.
Also attaching our floor plan... Bedroom 4 is the room super cold... Also tried to label the position of our garage and our furnace... Hope it helps.
Thank you very much for your advice in advance!


[Update...]
Thanks everyone for the advice!
I borrowed an IR sensor from a friend and tested the air temperature from the duct in each room.
looks like all the ducts close to the garage have a lower temperature than others, 29 degrees vs. 38 degrees.
I guess bedroom 3 is warmer than bedroom 4 because it has one more register?
Also tried to figure out how the duct runs but with no luck...

Do I need to re-do the garage ceiling insulation, on a 2-yr old house Disappointed But Relieved Face? Or would put insulation on garage doors help? Our garage doors are just the builder-grade doors made of paper/wood...
Thanks again for all the advice contributed!
Images
  • Floor Plan.JPG
Last edited by No.6 on Jan 12th, 2020 2:44 pm, edited 1 time in total.
8 replies
Deal Guru
Jan 27, 2006
14869 posts
7823 upvotes
Vancouver, BC
Do you know approximately where the ducts run so that they get to bedroom 4? I suspect that since bedroom 4 seems also to be the furthest away from the furnace, the hot air duct may be travelling close to an unheated or underinsulated portion of the wall.

One other question - do you feel the air flow from the hot air duct increase when the furnace is running?
Member
Jan 12, 2007
295 posts
136 upvotes
Take a look in the attic. The insulation could be unevenly packed.
Deal Expert
User avatar
Feb 11, 2007
15139 posts
16128 upvotes
Oakville
There's a good chance the crappy builder didn't put the required insulation in the walls and/or attic. You can take a look in the attic, but a cheap IR sensor can tell you where the cold spots are on your walls. FLIR camera makes it even easier.
Member
Jun 23, 2019
320 posts
161 upvotes
It seems like the duct for bedroom 4 must run through uninsulated space, most likely a garage wall which isn't properly insulated. The reason the room above the garage is warm is because most homes have the garage ceiling spray foamed to keep the room above warm. Perhaps the duct for that room runs through the spray foamed area of the ceiling or a wall that is insulated. If your basement is unfinished try and follow the ducts that look like they go near the garage/are for bedroom 4 and you can see if that duct runs somewhere uninsulated.
[OP]
Jr. Member
Sep 10, 2006
119 posts
38 upvotes
Toronto
Thanks craftsman for your reply. Yes i can feel the air flow increases when the furance is on.
have no idea where the ducts run though... the garage ceiling is finished and everything seems hidden in the wall
craftsman wrote: Do you know approximately where the ducts run so that they get to bedroom 4? I suspect that since bedroom 4 seems also to be the furthest away from the furnace, the hot air duct may be travelling close to an unheated or underinsulated portion of the wall.

One other question - do you feel the air flow from the hot air duct increase when the furnace is running?
[OP]
Jr. Member
Sep 10, 2006
119 posts
38 upvotes
Toronto
thanks TAZ99. I did check the attic and the insulation looks ok...
I feel the duct or garage is the problem, as the tempature from the air duct drops a lot in that room...
TAZ99 wrote: Take a look in the attic. The insulation could be unevenly packed.
Deal Guru
Jan 27, 2006
14869 posts
7823 upvotes
Vancouver, BC
No.6 wrote: Thanks craftsman for your reply. Yes i can feel the air flow increases when the furance is on.
have no idea where the ducts run though... the garage ceiling is finished and everything seems hidden in the wall
With the increase in airflow, is the air coming out of the duct warmer or about the same?

Also, if you remove the register, can you tell what direction the duct is running in? If you have a small mirror and a flashlight, you can also insert it into the opening (ie with the register removed) to see approx. how long the duct runs for and if you are lucky, what direction it turns next to give you an idea of where the duct goes as it's hidden in the walls.
Deal Addict
User avatar
Aug 12, 2007
4339 posts
711 upvotes
Waterloo
No.6 wrote: [Update...]
Thanks everyone for the advice!
I borrowed an IR sensor from a friend and tested the air temperature from the duct in each room.
looks like all the ducts close to the garage have a lower temperature than others, 29 degrees vs. 38 degrees.
I guess bedroom 3 is warmer than bedroom 4 because it has one more register?
Also tried to figure out how the duct runs but with no luck...

Do I need to re-do the garage ceiling insulation, on a 2-yr old house Disappointed But Relieved Face? Or would put insulation on garage doors help? Our garage doors are just the builder-grade doors made of paper/wood...
Thanks again for all the advice contributed!
With the Thermometer check the cieling of the garage. You should be able to tell where the vents run thru it. For now just add some insulation on the ceiling along the vent and possibly do the project when its more convenient.
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