Dash AC Vent Hoses - Shorten/Insulate?

[Bill R]

While doing some work on my cup holder pull out, I saw my Dash AC Vent hoses.  See Pic below.  It seems to me that there is a lot of excess hose.

Because of the plus 100F Texas summer days, I wonder if it would be advantageous for cooling efficiency to remove the excess and insulate around these hoses.   I know that this area of the front compartment has little insulative property to the outside.

Thoughts?

 

 

[Seward G]

I shortened mine.  

[timaz996]

It can only help.

[DavidL]

You can straighten the hoses out to get more flow out the intended duct.  Since the duct hoses are inside the RV, the cool is just cooling near your feet.  If you insulate it, then more of the BTUs will go out the duct exit.  But less cooling around the hose area so insulating them is a pro / con decision.  If you make the hoses more efficient, then you won't have as much issue with needing insulating.

[Gary 05 AMB DST]

In commercial sheet metal duct work, they used to tell us that a 90 degree turn was the equivalent of adding 10' to the length of the run. The 4" flex pipe isn't equivalent to a larger size pipe but there is a bunch of turns that can eliminated and get more volume to the vents. That photo turned my stomach.

Gary 05 AMB DST

Edited December 9, 2022 by Gary 05 AMB DST
misspell

[Gary Cole]

I agree with Gary. Dave makes a good point. However the temperature of the delivered air plays a large part in the sensory perception of cool in HVAC systems. . Rough interior flex is even more of an obstruction to air flow. Many OEMs avoid flex for that reason. In our case a better system would be insulated snap lock and a short piece of flex at the outlet if needed. After reading this discussion I wish that I had of done that when I completely replumbed my mess of a system this summer. Anything one can do to increase airflow over the evaporator and prolong compressor runtime is going to help. The duration that the compressor is shut down by the evaporator thermostat when it senses 45 degrees or so and also throttled by the expansion valve is lost and very much needed cooling Btu's.

Edited December 9, 2022 by Gary Cole

[Bill R]

So I ended up removing over 4 feet of vent hose.   Turns out that the lines with excess length were all floor vent lines.  Not so sure how much more efficiency I may have gained, but definitely a better install.  See pic below.

As I was doing this, I discovered another issue that I will start a post under a new topic.  Thank you for everyone's input on this one.  

 

[timaz996]

Wow, excellent job. I’m sure you will feel an increase in airflow. That’s how the factory should’ve done it. Nice work.

[Gary 05 AMB DST]

Don't stand in front of those vents!

Gary 05 AMB DST

[Gary 05 AMB DST]

55 minutes ago, Bill R said:

So I ended up removing over 4 feet of vent hose.   Turns out that the lines with excess length were all floor vent lines.  Not so sure how much more efficiency I may have gained, but definitely a better install.  See pic below.

As I was doing this, I discovered another issue that I will start a post under a new topic.  Thank you for everyone's input on this one.  

 

Now that we can make out what you had, are those vent hoses coming off of the heater, air conditioner box? 

Gary 05 AMB DST

[Bill R]

@Gary 05 AMB DSTThese hoses are coming off the Plenum Assembly Diverter Box in the generator compartment.  This is after the blower which is after the Heating and Cooling coils.