Cold Basement. (6-8'c difference with main and 2nd floor)
Before the basement were finished, the temp is usually around 20'C. (The main floor is always set to 23'C year round)
But now, when the main floor is at 23'C, the basement is constantly at 16'C.
This is the same during winter when it is -20'C outside, or summer like now when it is 30+'C outside. (So I dont' think it is due to insufficient insulation)
I know cold air sink and hot air raise, but 6'C difference seems like a lot...also why would the difference became so much more after the basement is finished?
I tried shutting off all the vents now since it is blowing cold air now (The shut off is not air tight), but temp is still hovering around 16'C...
Any idea why that is and how I can minimize the temp difference?