Yea, definitely the CPU fan. I figured it was from the start because the other fans wouldn't ramp up that loud if the CPU was getting hot. The chassis fans should be running off of system temp.
No. Certain fans like Noctua fans are made specifically to be silent with a lot of static pressure. They don't go above a certain RPM which is where your noise comes from on fans.
Your loudness is your CPU fan at 5000, hands down. Replacing with any of the above mentioned CPU coolers will drop that down drastically below 2000. Most if not all Noctua fans have a max RPM of 1200 a piece and with their resistor connector are inaudible at 700RPM. Your other fans are fine, it's that CPU fan that is noisy.
What is your ambient temp in your house? Shouldn't the sun be down in Canada right now?
How looks over the water and the sunsetting means the sun streams straight into the house. The computer is sitting behind the TV which unfortunately gets the sun from about 3pm-8pm.
Feels around 26degrees I guess, hard to know though.
OK Suggest one of those 3 links and I will order it now.