Improving AC Air Flow

Its common knowledge among vigilant and DIY RV'ers that the air conditioning units in RV's are not installed with much care and the ducting is not very efficient.

There is a product from RVAirflow that takes care of these deficiencies in one upgrade.

Like many RV-DIYers I decided to make and install my own. There are many versions of this mod on the Jayco RV forum such as this one: https://www.jaycoowners.com/forums/f64/seneca-a-c-airflow-mods-81502.html printed on a 3D printer.

My Unit, Better Than Most

I have to admit that I was surprised at how well my unit was taped when compared to pictures I had seen of other installs. 

Frankly, we did not think the noise was objectionable and the output at the vents seemed pretty strong. I decided to go for an improvement anyway.

A Different Material Than Most

After reviewing the other approaches to improving this ductwork I decided to use cardboard as the ducting material. Then while walking through Walmart I noticed the foam board and thought why not!

The Approach

I decided to try just cutting transition sheets from the foam board. These would be sections that would direct the air from the main output duct into the side ducts. I would use a combination of foam board and metalized ducting tape.

I decided to leave the stock centerpiece in place as it looked to provide a good seal.

Transitioning to The Side Ducts

I cut pieces of foam board that would fit from the source duct down to each of the ceiling's side plenums. I annotated the cut pieces with dimensions so that if you have the same unit they might keep you from fiddling to get a good fit.

Note that I cut the passenger piece on the wrong side of the material so it's installed with the blue backing outward.

These parts were taped in place with the Al tape insuring that all gaps and transitions were covered. Finish taping these parts fully before going to the next step.

The driver side

The passenger side. I cut this upside down.

Shows temp install .... before the final taping

First Section Taped

The Lower Baffles

Baffles were cut that provided the lower part of the new ducting. The apex of these two pieces fit against the center of the source opening splitting the airflow in 1/2. The dimensions for these pieces are also written on the part.

The passenger side to left

The driver side

Both installed 

Finishing The Install

The lower baffles are taped. Ensure that all the openings are taped shut. I taped the gaps at the edges near the ducts from the board to the frame to complete those transitions.

The Center Baffle

After assembly, I noticed that there was air leakage around the tape where it was applied to the center baffle. The tape does not stick to the stock center baffle material. Therefore I taped from the output side of the air conditioner down and around the center baffle and connected it to the input side which has a metal surface.

Fully Encapsulating the Center Baffle With Tape

Measurement Tool

I used an anemometer I bought from Amazon attached to a piece of 3/4" foam board to get a seal at each vent. 

Conclusions

In regard to using the foam board, I found it easy to cut and form with a sharp utility knife. It is also light, cheap, and readily available. The Al duct tape sticks to it well and it takes up less space.

I measured the airflow from each vent before I started. The airflow varied and it was hard to get a perfectly solid measurement. Later I discovered the AVG function on my meter, that would have been a better way to measure. In any case, I logged the most steady peak value for each vent.

I think there is enough improvement evident in the results below to consider this a worthwhile modification. I do not know if the results for Row 2 & 3 on the passenger side are the result of measurement error or what? In any case, one got a lot better and one did not change.

Enjoy and comment,

Don