sherlocktk
Well-known member
Last weekend I put in a new furnace/air handler and AC system. Replacing a system of the same specs/CFM. I am posting this to share what I have found and what has worked for me. This was "inspired by" the After Reading the "New AC unit, air handler crazy loud"
Old System was a 5 ton AC system where all the heating components are in the garage. Old air handler was "clean" and measured with an anemometer around 1900-2000 cfm delivered. based on wind speed measurements/square inches. For those that care my overall static pressure is around .2 as measured with a very cheap and accurate water in the tube method.
I had to change the old system, and put in a new furnace/air handler. The new one was MUCH louder at the same CFM. I started to look into the differences between the old vs new.
The new one did NOT have any fiberglass matt on the inside of the blower compartment where the old one did. This was my first clue. I purchased some 1 inch 2x4 fiberglass boards for HVAC on amazon, and cut them to fit and lines the entire blower compartment. This made a huge difference. Since I had some extra board I decided to put one on the bottom of the return, this also had a meaningful impact. There are now no reflective surfaces between the return and the air handler, and I can now have a conversation next to the return of my system while moving almost 2000 cfm.
In short line with duct board, its expensive but its a buy once cry one item.
Old System was a 5 ton AC system where all the heating components are in the garage. Old air handler was "clean" and measured with an anemometer around 1900-2000 cfm delivered. based on wind speed measurements/square inches. For those that care my overall static pressure is around .2 as measured with a very cheap and accurate water in the tube method.
I had to change the old system, and put in a new furnace/air handler. The new one was MUCH louder at the same CFM. I started to look into the differences between the old vs new.
The new one did NOT have any fiberglass matt on the inside of the blower compartment where the old one did. This was my first clue. I purchased some 1 inch 2x4 fiberglass boards for HVAC on amazon, and cut them to fit and lines the entire blower compartment. This made a huge difference. Since I had some extra board I decided to put one on the bottom of the return, this also had a meaningful impact. There are now no reflective surfaces between the return and the air handler, and I can now have a conversation next to the return of my system while moving almost 2000 cfm.
In short line with duct board, its expensive but its a buy once cry one item.
