New Mod – Air Conditioner Baffle Box

Written by Lee

For those of us who aren’t fortunate enough to be somewhere with a reasonable temperature and a comfortable humidity, an AC or two (or in some cases even three!) are a blessing. I know that for me they are an absolute requirement. They are also NOISY. I love the fact that the one in our bedroom is loud, because it makes excellent white noise which helps both of us sleep. In our rig, the bedroom is in the back and the AC is only 44″ from the bed, and when we run it with the AC blower set to “high”, which is always, the dB level is a whopping 68 dB. For reference, that’s about the equivalent of a food mixer. By comparison, when it’s NOT running, the room measures around 35, which is the same as a quiet library.

Our other AC is in the kitchen, but all the way at the end, so it’s right next to the living room. That puts it just a little off to the side of the chair I sit in to watch TV and movies, and it’s also pretty loud. It’s much higher, at 98″, and it measures at 68 dB as well. With the temperatures being 100° more or less every day in the San Antonio area for the the past month or so, I decided to do some poking around to see what I could do to help reduce the noise.

 

There are a variety of things that can contribute to why an AC is louder than it needs to be. Here are some things to check first:

Is it loose?
If the AC is not secured well, it can vibrate, and that can really make the noise louder. Check the mounting bolts to make sure they’re tight.

Are the seals/gaskets bad?
If it’s a much older unit, the rubber seal between your rig and the AC might be bad, and the rubber could have hardened, again causing vibration.

Is the fan out-of-balance?
An out-of-balance fan can make a ton of noise.

Is the airflow restricted?
Take off the inside cover and filter and look around inside the chamber. Anything that is in the way of the air flow can add noise as the air rushes past it. Try using zip ties to bundle wires together and secure them off to the side away from the air flow. You can also use furnace tape to secure anything and create a smooth surface for air to flow over.

If you’ve done all the inspecting and everything you can to make sure that it’s not making more noise than it’s supposed to, and you still want to it to be quieter, you can either buy an AC “silencer kit” or make one yourself. I took a look at the pre-made kit and decided that it was way too much money for a big piece of plastic, and decided to try making my own. For those with money to burn, who don’t want to, or can’t make one, here’s a link to the manufacturer:

Dometic RV A/C Silencer DA100

Before we go any further, I want to point out that both the commercial product above, and my version are designed to work with AC units that have the “standard” interior ceiling cover that  consists of a grill that has holes or slots for air intake, and in some cases a “dump” valve. A dump valve allows you to “dump” all of the cold air directly from the AC unit straight down and out into the room, as opposed to directing that cold air throughout your rig via ductwork.  I also want to mention that the “Wacko Products” version removes the option of using the dump valve, but my mod does not. You can still use the dump valve with my version.

The commercial version essentially works by offsetting the air intake to the side by about 50%, reducing the open area,  and adding some noise dampening material. It seems to look pretty nice and there are plenty of people out there who have made videos and reviewed it. I have not owned one or tested it, so I cannot endorse it. You should thoroughly research it before you spend the money. Do some Google searches and watch some videos and definitely read reviews. It’s a pretty good chunk of money to spend to not be happy with the end result.

(We started with the idea of buying one and when Lee showed me the video I personally didn’t think the noise reduction in the video was worth $189. Of course I don’t sit in that particular seat and the AC noise is much less of a problem where I do sit.  If Lee really wanted it of course we would have tried it, but I love when he puts his MacGyver skills in action.   – Trace)

If you’re comfortable tinkering and want to try making one of your own, here’s my frugal version. It really not at all complicated, and also relatively inexpensive.

Here’s a material list.  I measured the interior AC cover and added an inch or so on each side for the dimensions.

$ 14.88 – 8′ primed 1″x 4″
$   9.41 – 2′ x 4′ luan
$ 21.56 – 4′ x 8′ white polywall panel (in the paneling section, and matches most ceilings in rigs. It’s the most expensive part of the project, so you could just use the luan and paint or stain it)
$   4.69 – 2 2″ hinges
$   1.79 – magnetic catch
$   7.88 – furnace tape
$   8.98 – white gorilla tape (if you don’t have gaff tape. Why don’t you have gaff tape? I have been telling you to get some for years.)
$ 13.56 – 1″ x 1″ poly outside corner molding
$ 11.94 – 4′ x 8′ x 1/2″ foam insulation board (I used some leftover carpet padding, you can use almost any sound dampening material)

If you don’t have any of the materials, and you have to buy everything it will cost $95.  If you want to be more frugal, you can skip the metal tape/gorilla tape and use duct tape.  You can also skip the poly wall sheet and use some old rolled up t-shirts or other fabric as the sound insulation.  Those changes will lower the cost to less than $50.

I chose these materials after making a “proof of concept version” with what was lying around, and decided that instead of something that would need to be stained or painted and color match I would just go with white and hope that it would blend in.

(The “proof of concept” was heavy, clunky and pretty ugly.  As much as I appreciated the initiative, I really didn’t like the way it looked.  Lee quickly reassured me that the final version would be lighter and prettier which it was. – Trace)

The construction is very simple, it’s just three sides of the 1″ x 4″ assembled with finish nails and then I added a 1″ x 1 1/2″ piece which as you can see leaves an opening for air to enter.

 

 

Then I attached the sheet of luan, added the layer of textured plastic sheeting and miter cut the corner trim.

 

I flipped it over and added three layers of 1/2″ carpet padding. The white area you see at the bottom is the white Gaff tape. I wanted to use that instead of the metal furnace tape at the entrance because I wanted to see if the rough texture of the gaff will “catch” any airborne particles before they hit the grill and filter. I thought maybe the smoother furnace tape wouldn’t catch them. I don’t think it matters what you use, as long as it holds the material in place. You could also use pretty much any sound dampening material inside. I used carpet padding because I already had it, but you could use foam, towels, blankets, insulation, anything that will absorb and dampen sound. You can also see the metal magnetic catch in the lower right corner.

 

 

Once it was all set I added the hinges.

 

Then I hung it up. Most rigs will have some wood framing around the AC hole in the ceiling, but check to be sure, otherwise the screws will just fall out of the thin paneling of the ceiling. Also be sure to avoid hitting any wiring with the screws. Use the shortest screws you can, and make sure you’re going into wood and that will keep you out of trouble with the wiring.

 

 

 

Finally it was just a matter of attaching the metal plate to the ceiling for the magnetic catch, and swinging the box up on the hinges and letting the magnet hold it in place.

 

See pretty 🙂 – Trace

 

Although we drove 1200 miles with this in place, the magnet never pulled away from the metal plate. But even if it had, it would just swing harmlessly down. When it’s “closed” the bottom of the box is 92″ from the floor, which is plenty of clearance. In our rig, when it’s “open” it’s still 75″ from the ground. And because it can be opened, the “dump” valve is still available to us, which is nice.

Lee grabbed me last minute to do the demo. I am a bit of a mess 🙂 – Trace

After installation, it was time to check the sound level! From the same position as before, with all other factors being equal, the meter gave us a reading of 62 dB, for a net reduction of 6 dB!!! This might not seem like a lot, but it is a massive amount. The decibel scale is logarithmic, not linear. This simply means that for every 3 decibels you move up or down the scale from 0-194, you are adding or dropping 50% of your remaining sound pressure levels to your exposure. By dropping 6 decibels, for instance, you first move 3 dB, and then another 3 dB. For each 3 dB you drop, your sound pressure levels will drop another 50% of the remaining sound pressure.   The following table will help illustrate the order of magnitude associated with dB:

dB-Drop                       Survival Rate

1 dB Drop                     79% of your noise has survived
3 dB-Drop                    50% of your noise has survived
6 dB-Drop                    25% of your noise has survived
9 dB-Drop                    12.5% of your noise has survived
10 dB-Drop                  10% of your noise has survived
20 dB-Drop                   1% of your noise has survived
30 dB-Drop                 .01% of your noise has survived

So for our purposes here, we reduced the sound level 75%! That is a significant amount of improvement, especially considering I spent about two hours and $ 100 on it, and now I can watch TV without sitting in a pool of my own sweat and turning up the volume to absurd levels.

 

(For those non-techy, non-math geeks like me, essentially it was quieter when you stood directly beneath it.  In other areas of the room, it didn’t seem to make a huge difference but directly underneath absolutely.  Since the chair is almost directly underneath it, it will certainly make Lee’s life more pleasant.  From my perspective it was relatively cheap, Lee had lots of fun making it, and it looks like it came with the RV.  Those are my criteria for a good RV Mod! -Trace)


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Simple RV Mods We Wish We Would Have Done A Long Time Ago

When you are working and traveling, it isn’t often that you have the time or money to make modifications.  You think about them, but real life usually gets in the way and they just don’t get done. (No matter how interested I am in doing these things, I am always very wary of starting something and running out of time. Everything always takes longer than I think it will, sometimes by as much as 100%. And we usually aren’t 15 minutes from a hardware store or Home Depot or Lowe’s, so that’s also a factor. Running back and forth for pieces and parts is a much bigger deal when it’s an hour in each direction. – Lee)  Thankfully though we are in one place for an extended period of time, and for once have both the time and the money. (We’re also 15 minutes from a Home Depot! – Lee) It’s also been super hot (still hitting 100 degrees every day) and Lee would much rather be inside than out.  I just try to keep out of his way when he gets rolling and not do anything to slow him down.

The first modification was to add to the storage area under the bed.  Like most RV’s our bed has storage under it. The mattress sits on a box, and on top of the box is a “lid” with a hinge. There are gas lifts on the lid that assist in lifting it and the mattress to give us access to a nice little storage area. The part of the box that is at the head of the bed is in the slideout, and the rest of it sits on the floor. All of the box is one piece, but only the part that sits on the floor is storage. (That storage area is 4′ wide, 29″ long and 16″ deep, giving us a total volume of  12.8 cubic feet. – Lee) We didn’t know for sure what was in the other remaining space of the box, but Lee wanted to check it out and if possible reclaim the space. (You know I like to reclaim space. Here is a post from a while back where I found some wasted space inside the rig that significantly increased our pantry area, it’s the last mod on the page. And another where I increased the space in a small baggage compartment by almost 50%! That’s near the end of the post. – Lee)  In order to get to it he had to pull the mattress completely off and then look at the bed. He then removed that section of board and found a huge unused space underneath. (Reclaiming that space was pretty straightforward, but required a little bit of re-engineering of how the box was used. The original design has the lid attached to the non-opening box top with a few hinges. That anchors the hinges, and if I used the that top for a second lid, then the entire top wouldn’t be anchored and would just slide around. You can see in the picture below the section of the top that is not the lid, the lid is under the mattress. – Lee)


(There’s a lot of pressure on the hinges from the gas lifts, plus the wood is only 1/2″ thick, so you can see where the screws, which were not quite 1/2″ had worked themselves out of the wood over time. – Lee)

(So this is what I found under that second section of top. Just a nice big wasted space. – Lee)

 

(Because our slides are elevated 6″, this space is not quite as deep as the existing storage, but it’s nothing to sneeze at. This is an area 4′ wide, 29″ long and 10″ deep, for a total volume of 13920 cubic inches, or 8 cubic feet. It’s essentially the same as the “front” space, except that it’s 6″ shallower. So we ended up with 20.8 cubic feet instead of 12.8, a 38.5% increase!!! That’s a LOT of space in a rig to just magic out of thin air. Here’s a helpful idea of what you can do with 8 cubic feet, represented by a woman holding a box that’s 3 cubic feet. So imagine if she had absurdly long arms and could hold 2.66 of those boxes! – Lee)

(In order to create a new hinged lid for that “back” area, I needed to cut the plywood into three pieces. Two narrow strips to use as “anchors” for both hinges, and one large piece to serve as the lid for the back area. I didn’t want to cut it myself, because with hinges you really need perfectly straight cuts, so I went to Home Depot. They will do cuts on a panel saw for free, but of course I had to buy the wood, which is OK because I had another plan for the piece I took from under the mattress, which I will cover in another post. I also decided to replace the hinges that were already there, they were just not heavy enough. Once I had the wood cut I put one strip all the way against the wall and added the hinges and the other in the middle, to anchor the original lid. I also added a piece of lumber to “bridge” the gap between the lid and the hinge anchor so the thin plywood wouldn’t bow in the middle once there was weight on it. – Lee)

It was relatively simple to do and made us both wonder why we hadn’t done it before! It actually took longer to figure out what would go in there (seldom used items like winter coats, sleeping bags, etc) than to do the work. (The best part of this is that it allowed me to take 1/2 the stuff that was in the “front” storage under the bed and put it in the back, which is all stuff we will hardly ever need, freeing up the space in the easier to access front for things we will need more often. Here’s what I was able to put in that reclaimed space: Queen size air mattress, 2 adult sleeping bags, 20 XL T-shirts, 4 sets of long johns, a pair each of dress shoes, cowboy boots and steel toed work boots, 6 long sleeve dress shirts, a spare set of queen sheets, a full size memory foam pillow, 8 pairs of over the calf socks, two belts, 2 ties, a shoe shine kit, and 4 pairs of jeans. – Lee) 

 

Next up was replacing our television set in the bedroom with a smart TV.  (A smart TV allows you watch streaming channels like Netflix, Amazon, Hulu, etc, by using your WiFi. You can also put video files on a USB stick or external USB drive and plug it in to the TV to watch those files. – Lee) I never watch the TV in there because it is too small for me to see and Lee never watches it because he can’t use a memory stick to play files we have.  Replacing the old 27″ Furrion with a 32″ ROKU TCL gave us both a larger screen and smart TV capability.  Best of all it was lighter than the old one and at $140 was a bargain!!  Again, big benefit for minimal cost and labor. (This was ridiculously simple, all I had to do was measure the space between the existing mount and the ceiling of the bedroom to make sure that whatever we bought would fit. I did NOT want to move that mount. Generally when those are installed at the factory, they use a large backing plate and if you remove the mount, there’s not necessarily anywhere solid enough to remount it. – Lee)

Lastly we finally replaced our microwave with a convection microwave. I remember vividly not wanting a convection oven as an upgrade when we ordered our rig, but as soon as I saw other people using theirs to bake I regretted it.  Baking in a propane oven is not fun.    I always said when the microwave died we would replace it with with a convection, but five years later it is still going strong.  Luckily Lee did some research and learned the company who made our microwave also made a convection version, in the exact same case!  This was important because it meant he wouldn’t need to do anything with the cabinetry or the wall mount.  It would just be a matter of taking the old one down, and putting the new one up. The convection oven was also only $370, much cheaper than I expected it to be.  So, Lee ordered the convection oven and voila!  Again, something I wish we had done a long time ago.

Original RV microwave

 

Space once it was removed. I was able to help with this. Lee held it up while I took out the screws in the top that hold it in place. Most of the weight is on the bracket on the back wall. Once the retaining screws were out the two of us tilted it forward and lifted it off the bracket together.

 

The one thing I will say about this change was having two strong people really helped when we put the new one up.  It’s possible Lee and I would have been able to do it, but having Greg who is both tall and strong was a definite benefit.  There is a metal hanger that the old one slid off and the new one had to slide on.  Once it was on the hanger one person had to hold it while the other screwed it in.  It’s a tight space and the convection oven is a bit bulky so Greg really helped.

The guys bringing in the new microwave

 

It was hard to slide it on the metal lip

 

Voila!!!

None of these jobs was particularly difficult, but you have to know what you are doing.  So far I really like the convection oven.  I baked cookies and egg rolls and they both came out really good.  I was a little intimidated at first so I read the manual, and it is important that you use the right cooking containers depending on which setting you are using.  I even watched a couple of You Tube videos, which helped a little, but they both said to adjust the temperature down from the recipe.  I didn’t find that necessary, however, and used the same temperature and cook times that the recipe called for.

Next up we reclaim some extra space by removing our RV oven and cooktop. This is a much harder job, and as such will be getting it’s own post. Stay tuned!


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