Improving A/C Duct Air Flow and Reducing Noise - Page 2

**creativepart** · 07-15-2021, 10:49 AM

That's great Don. This kind of info befits everyone with an internal A/C unit protruding their ceiling.

Another YouTube channel that has worked on this is Changing Lanes. Here's their video on their project:

https://www.youtube.com/watch?v=V9rEQb05Qv4

powercat_ras · 07-15-2021, 12:49 PM

Just keep in mind if you have a Winnebago with the Chille Grille you have to take that into consideration. Some of the solid foam deflectors I have seen will disable the Chille Grill functionality. Personally I open the chille grille vents a lot as it make the AC cool the living area faster, when cooling down my RV when it's hot or when I've been driving and the front section above the engine is warmed up and throwing off a lot of heat into the front of the RV.

rprochnow · 07-15-2021, 01:02 PM

During the last trip, with outside temps above 100 - I removed the insulation covering the air dump vent - and we started running the A/C with the generator on and the air dump vents open while driving - and that seemed to help keep the coach cooler.

But, once parked in the full sun, temps would slowly rise to around 91 inside during the peak afternoon sun and the outside temp around 108.

As a next step, may try to add the foam board to better direct the airflow to the ceiling vents (since the air dumps didn't seem to help that much) and see if we can get the A/C cool down better with the temps are really hot outside.

The best solution (if someone was handy) would be to create a flexible "Y" vent that could be sealed to the fan opening and the two side ceiling vent ducts - which would eliminate any air being sent into the plenum - and would only go into the ducts.

Until then, the best solution may be to seal off the air dump, and add something into the upper corners of the plenum and a triangular shape in the middle - to better direct the air and eliminate what is likely some turbulence inside the plenum box (which probably cuts down on some of the air flow).

Will also look at cleaning up the input side - and see if that helps further reduce the noise...

These are such obvious improvements - too bad Coleman and Winnebago doesn't do more to improve this on new units...

crah · 07-15-2021, 01:47 PM

I recently did the mod from the Why Wait YouTube channel with the foam cutouts. The only thing different that has to be done is the bottom piece cannot be the 1 inch thick foam because the View/Navion duct start right at the ceiling line. I used thin coroplast lined with foiled foam. Total of 1/4 inch thick. The mod works better than having the dump valves open. At 105 degrees outside, it creeps up to about 83 degrees inside at the hottest part of the day. Before mine would creep up to 91 degrees. This mod does help but still has airflow restrictions. The RV Airflow system would work even better. I've been in contact with them during the development stage, and they said about 6 weeks out for it to be ready for Winnebago.

Ontario Don · 07-16-2021, 08:22 AM

crah - Do you know why the RV Airflow system will not work for us right out of the box? rprochnow mentioned the dimensions were not compatible - what is the manufacturer working on to make it Winnebago View compatible?

Thanks, Cheers

crah · 07-16-2021, 09:03 AM

Quote:

Originally Posted by Ontario Don

crah - Do you know why the RV Airflow system will not work for us right out of the box? rprochnow mentioned the dimensions were not compatible - what is the manufacturer working on to make it Winnebago View compatible?
Thanks, Cheers

The cutout sizes are not the same and the entire foam piece they make was too thick. The foam piece from RVairflow is molded with the air channels that line up with the plenum ductwork the rv manufacturers make. Winnebago's plenum is not as thick (total ceiling is thinner) and their ductwork dimensions are quite a bit different. I had the piece they already make and ultimately returned it, as it really couldn't me modified to make it fit. I was working with either the owner or one of their engineers for a while and gave them dimensions of the View plenum. We left off that they would work on new molds. I'm guessing they are probably working with the manufacturers directly now to make sure all dimensions work. My last text to them last week was that they are about 6 weeks out for available to public. Hope that is the case.

Ontario Don · 07-16-2021, 09:52 AM

Ok, thanks for the info. Sounds like you are going to pick one up when it is available for the View, so looking forward to your review.

Cheers,

rprochnow · 07-16-2021, 09:57 AM

The RV Airflow solution is difficult to replicate DIY.

They make tight seals to the fan opening and the two ceiling duct openings, eliminating any air leaks in those areas. And by using the styrofoam mold, they are also able to eliminate any sharp edges in the paths from the fan to the ceiling ducts.

The foam board solution is an improvement, but it still will create air turbulence inside the plenum on the fan output side, because it leaves some of the plenum exposed - plus it doesn't seal tightly to the plenum openings.

The other feature of the RV Airflow solution is the underside of their product, which opens all of the input vents - and provides a curved path for that air to get up into the air conditioner. The foam board solution does open up the entire input vent - but it leaves a flat surface sitting directly above the vents, which could reduce airflow and also increase noise.

As I prepare for our next road trip in a few days, if I have time, I may revisit the DIY mods I've made to see if I can do anything else quickly as an interim solution - until the RV Airflow has a version that works with our 21D.

crah · 07-16-2021, 10:02 AM

Quote:

Originally Posted by Ontario Don

Ok, thanks for the info. Sounds like you are going to pick one up when it is available for the View, so looking forward to your review.

Cheers,

Yes I'm eagerly waiting on this and will do a review of it right away. Based on the homemade foam modification, I can already tell the RVairflow will help quite a bit. I'm hoping to get the rvairlfow while the weather remains the hottest in Vegas.

**creativepart** · 07-16-2021, 10:13 AM

This A/C problem is well known by everyone, including the A/C manufacturers. So much so that a business has sprung up to supply a fix for a universal design problem.

What's with these A/C manufacturers that sit back on a flawed design that they know could easily and inexpensively be corrected and yet they don't do it?

Surely some enterprising A/C company will fix this issue and become both a winner in the marketplace AND force the other companies to get with the program.

rprochnow · 07-16-2021, 10:48 AM

In addition to the poor air flow - the other problem the manufacturers should fix with their units is the surge when the units are powered up. The units should come with "soft starts" to reduce that unnecessary surge - or at least provide a recommended option that could be added by the dealers.

Though until the current surge in RV sales and component shortage is over, the manufacturers all have more business than they can handle right now - so it's unlikely we'll see any improvements for several years (if then)...

**creativepart** · 07-16-2021, 11:17 AM

Quote:

Originally Posted by rprochnow

Though until the current surge in RV sales and component shortage is over, the manufacturers all have more business than they can handle right now - so it's unlikely we'll see any improvements for several years (if then)...

The one promising thing about the current supply issues is that other brands are getting access into manufacturer's supply chain. Furrion is one, GE another and then there are a handful of European and even Australian companies making some inroads, too.

Both the EU and AU markets specialize in small Class B and Class C RVs not bigger Class As.

Furrion's new Chill RV A/C has made some important improvements - Rather than use one motor to operate both fans, (intake and output fans) like both Coleman and Dometic do, they use a separate motor for each for each task. It has 3-fan speeds and sleep settings, too. And, it has a soft start built in.

Another plus for the Furrion is that it can be used to replace a Coleman Mach or Dometic Penguin A/C and even includes a wiring adapter to work with the stock Coleman Mach thermostat. And, they have 14.5K BTU models, and 15.5K BTU models. So far though all I see are A/Cs only and not heat pumps.

And I've learned that RecPro has a line of A/C RV units that are heat pumps and according to their website is 4db quieter and uses 3-amps less than Coleman or Dometic. They also have two separate air flow tubes to keep the return air away from the cold air.

Quote:

Most RV air conditioning units blow the air from the top unit through the space between them and out of the bottom unit without a tube to control the air. With the air moving around in the space between, it loses some of the temperature quality and cleanliness. With the directional tube in this model, the airflow is controlled to provide optimal temperature quality and cleanliness.

So maybe things are changing a little.

**creativepart** · 07-17-2021, 10:45 AM

Truma has just announced a new RV A/C for US distribution. Sounds promising - they are trying to make the units much more quiet especially in "sleep mode"

Quote:

“The innovative and intelligent design of the Truma Aventa maximizes cooling while reducing noise. At the same time, we are balancing temperature and humidity to achieve the ultimate comfort zone,” stated Mark Howlett, Sr. VP of Sales & Business Development for Truma North America.

The Aventa will be offered in two models. The Eco model offers 13,500 BTU/h cooling capacity, while the Comfort models offer 15,000 BTU/h cooling capacity. Both Aventa models will be offered in black and white.

Compatible with ducted and non-ducted systems, the Truma Aventa comes standard with many advanced features, including automatic cooling mode, dehumidification mode, night mode, air circulation mode, and three manually selectable cooling mode fan speeds (low, medium, high).

Looks pretty promising!

rprochnow · 07-17-2021, 03:25 PM

Maybe Coleman will upgrade their units if they start getting competition with better technology...

Though for those of us with Coleman units already, the RV Airflow solution will be much less expensive - if it can help cool better, even if it's not as good as what Truma is bringing to market.

WV Bum · 07-22-2021, 08:08 AM

Should you run the engine while connected to shore power in the View. dealer said I shouldn’t ?????

**ThomB** · 07-22-2021, 08:47 AM

Quote:

Originally Posted by rprochnow

The best solution (if someone was handy) would be to create a flexible "Y" vent that could be sealed to the fan opening and the two side ceiling vent ducts - which would eliminate any air being sent into the plenum - and would only go into the ducts.

Someone did this and is selling the unit he made. Simon Leung, where are you?

This is what he created:https://dragonfly2.net/shop/ols/prod...rflow-diverter

He's on one of my Facebook pages for Winnebago Vista's and 3D printed a diverter that ill fit the plenum from the roof and direct into the cut-out vents. This was for a Vista so you might have a little different setup, but he's pretty good with the design took and had a really nice design. He's on this forum as SimonSKL.

crah · 07-22-2021, 12:32 PM

Quote:

Originally Posted by ThomB

Someone did this and is selling the unit he made. Simon Leung, where are you?

This is what he created:https://dragonfly2.net/shop/ols/prod...rflow-diverter

He's on one of my Facebook pages for Winnebago Vista's and 3D printed a diverter that ill fit the plenum from the roof and direct into the cut-out vents. This was for a Vista so you might have a little different setup, but he's pretty good with the design took and had a really nice design. He's on this forum as SimonSKL.

Wow great information and thanks for the link. Based on my measurements the View plenum is nearly identical. Have you tried this mod and have feedback on its performance?

rprochnow · 07-22-2021, 05:41 PM

Has anyone tried Simon's diverter in a View/Navion?

Since the plenum measurements might be different (height, location/size of the side ducts), the part might not work for View/Navion RVs...

If it does work - could be a better solution than the styrofoam...

crah · 07-22-2021, 05:57 PM

Quote:

Originally Posted by rprochnow

Has anyone tried Simon's diverter in a View/Navion?

Since the plenum measurements might be different (height, location/size of the side ducts), the part might not work for View/Navion RVs...

If it does work - could be a better solution than the styrofoam...

I just ordered mine. The dimensions are pretty much identical. I'll report back once I get it.

rprochnow · 07-23-2021, 06:20 PM

According to an e-mail from Simon, he's not aware of anyone who's tried his product in a View/Navion...

Does it fit?

And, if it does - does it improve air flow enough to bring temperatures down faster while also reducing the noise level?

Though after adding Simon's product, you should also be able to add some insulation around the diverter which could further reduce fan noise.