I found this the other day on another RV forum, and it really looked well-thought-out by the poster:
Beat the heat ? Improving air flow from the air conditioner ceiling unit | 2001 Coachmen Mirada 300QB

I just finished up doing it to my Dometic Brisk-Air 13.5k BTU, and it's like night and day.

Highly endorse this mod for those with non-ducted A/C in your rigs!

Pop

 

Good idea. Sometimes it is the simple things that make the biggest difference.

 

I have a history of HVAC work and in the past, in order to increase air flow, I formed what are called "turning veins" out of sheet metal and that also worked well. You will note on that unit, the air velocity is normally greater on one end than the other coming out of that cover.

Steve

 

I suspect that the air flow is so much greater that I may have to add some way to prevent the filter from being sucked into the air return intake. A small inconvenience to pay for the added flow.

The foam filter is flowing freely now (it's clean) and remains in place, but once it begins to get dirty, and offers some resistance, it might lift and be lost.

I'm thinking 1/4-inch hardware cloth, cut-to-size, and a small tie-wrap near the center would prevent all that.

Pop

 

Ordered the vents for this mod....what a no brainer. Should have come this way.
Thanks for the info.

 

Yup. That's a lesson the factory could have learned!

I did decide on hardware cloth to retain my foam filter.

It's 1/4-inch, and the ends have been turned around to keep down the snagging.

The two white dots are small tie-wraps to hold it in place.

Pop

 

Nice tip. We have a 19ft trailer and the a/c is always blowing on us in the bed. This is a great fix!

 

Did this mod, incredible how much air it pumps out. Bought these vents.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1