Styrofoam block in A/C unit?

[Maximus216]

So I just did my coleman in the living area. I bought the wrong size insulation board so i had to stack it. I left about 1.5 inches of space between the block of foam and the bottom piece that was used to seal it up. I taped off all around the block of foam before putting the final piece in. Nothing is going to seep out around the edges. I thought about putting in a divider for the left and right duct work but decided against it.

[TheLexx]

Nicely done! Let us know what kind of improvement you see and feel!

So I just did my coleman in the living area. I bought the wrong size insulation board so i had to stack it. I left about 1.5 inches of space between the block of foam and the bottom piece that was used to seal it up. I taped off all around the block of foam before putting the final piece in. Nothing is going to seep out around the edges. I thought about putting in a divider for the left and right duct work but decided against it.

[bcdiesel]

Bad news for me... I ordered one kit and chose the cheapest USPS shipping for $18. I was fully aware that UPS would screw me for brokerage crossing the border to Canada so I always avoid them. I guess RV Airflow thought they were doing me a favour and appears to have upgraded to UPS instead of my USPS choice on checkout. UPS wants $90.97 to deliver it to me!!! Canadians beware. I’ve emailed RV Airlflow to ask how this happened but I’m not going to pay the stupid brokerage; taxes I get, but not $60 brokerage. Awaiting a response.

[Maximus216]

Nicely done! Let us know what kind of improvement you see and feel!

I can only run one AC at a time right now since at home i only have 30 amp service. When I run the main unit i can tell a big difference in the bedroom. Quite a bit more air is coming out of the bedroom vents.

[KamFlyer]

Bad news for me... I ordered one kit and chose the cheapest USPS shipping for $18. I was fully aware that UPS would screw me for brokerage crossing the border to Canada so I always avoid them. I guess RV Airflow thought they were doing me a favour and appears to have upgraded to UPS instead of my USPS choice on checkout. UPS wants $90.97 to deliver it to me!!! Canadians beware. I’ve emailed RV Airlflow to ask how this happened but I’m not going to pay the stupid brokerage; taxes I get, but not $60 brokerage. Awaiting a response.

Thanks for the heads up. I just ordered one yesterday and chose the USPS option. It hasn't shipped yet so I send a message requesting to not upgrade the shipping and use USPS as requested. Hope they see it before it ships!
-Rob-

[srobins]

I have read through most of these posts and they appear to be all directed to owners with the Coleman Mach A/C units. My 2018 297RSTS came with two of the Dometic Brisk Air II units. I think we all agree that the most rapid cooling of the unit takes place when the Dump Slots are open. The downside to this is that the units produce more noise.

What I have found is that if I remove the section of the Air Box that that the Air Dump slide openings are in the noise from the unit is significantly reduced. This allows the air to blow directly into the camper without any restriction. While I am not an audio engineer and have not tested this with a decibel meter, I am guessing that the sound is reduced by 40 - 50%. I was actually amazed at how quieter the unit is.

I would suggest anyone with a Dometic Brisk Air II give this a try. Both sections of the Air Box (Intake/filter side and air dump side) simply slide off. I have attached a couple of pictures. In the center where the two sections meet there are a couple of slots that you can slip a flat blade screwdriver in to ease removal.

[lnesomdove]

I have looked at this mod and your diagram closely resembles the functionality of the RVAir flow product. I fashioned my own over the weekend and since I wanted to keep the air shower/dump function, pretty much did what your picture shows but left out the bottom piece. My theory here is that with my dump vents closed, I can't feel any air coming through them; if any is coming through it has to be minimal.

I shortened the box like you, pretty much giving the air no place to go but sideways, which in theory should result in less air turbulence in the box. My concern with the triangle piece inside (and same concern in the RVAir product) is, what if this unit is off and your 2nd AC is running. Where does the air go when it hits this dam? If you had colored smoke, one might see it go up into the unit (would it cause a dam and force the air back down?) Hard to say. Your implementation might lessen the impact due to its size, but the RVAir flow one seems more apt to push that air into the unit.

Leaving out the bottom piece and condensing/compressing the box, I feel like I did get air flow improvement. Where I once heard a whistle at the unit, that whistle is gone. My Coleman Units are already much more quieter than Dometic ones so I don't know that I got a gain there. Overall, my mod cost me about $10 for tape (had the foam from a cooler laying around) and about 2 hours total.

Good work!

[TheLexx]

My concern with the triangle piece inside (and same concern in the RVAir product) is, what if this unit is off and your 2nd AC is running. Where does the air go when it hits this dam?

That's a great point. The racetrack system is designed to allow for the free flow of air throughout the whole system. The triangular diverter could in theory, act as an obstruction. I suppose you could lower the height of the triangle so that it's not so much of an obstruction.

[lnesomdove]

Maybe I am overthinking some of this but even with both AC units operating, there really is no directional flow. Positioned on opposite ends of the camper, the flow comes down from the unit similar to the way a downdraft happens from a thunderstorm. If both are on doing this, maybe they meet halfway, obstruct each other, increase back pressure which causes the air to flow out the closes vent?

But design wise, still wrestling with the RVAir flow design as it suffers the fate of air being pushed back up into the unit (causes a dam too?) Who knows, I'm not an engineer, just a DIYer right? Either way, our solutions are just as effective and a whole lot less money. And if it works, who is going to look up in your AC unit and say, that looks like crap? No one! I'm all for functionality over beauty on this one

[bertschb]

We just installed the RVAirFlow "system" in both our AC units. The design of the system is actually pretty good. The gaskets on both the main styrofoam block and the side vents are well thought out and should prevent air from leaking around them. We do notice significantly more airflow. Some chunks of construction debris actually blew out of a couple of the ceiling vents. They are quieter as well. But, we won't know how effective the system is overall until we're somewhere with a 100 degree day with no shade. That will happen for sure this fall when we return to our spot in Palm Springs. Our RV can handle temps up to around 100 with no shade with both AC units running. Once the temp hits 110, it's mid-80's in the RV by late afternoon. We're hoping the RVAirflow system allows us to camp comfortably with outside temps up to 105-110. But, this system may not make any difference at all (other than it being quieter). Only time will tell.

I will say the instructions are HORRIBLE and their "installation video" is worse. My wife and I probably spent two hours on the first AC unit trying to figure it out. The second unit took about 20 minutes and most of that time was spent adding foil tape around each vent to make sure they were tightly sealed with no gaps to reduce airflow. RVAirflow needs to hire somebody who actually knows how to write installation instructions.