Insulation of ac unit increases cooling?

[norty1]

I completed the inside insulation inside the air box last week. Today I started on the outside insulation. Took about an hour to do one, so I just finished them both up.
I did have to separate the snap on shroud to get it back on as the insulation is right against the shroud.
Hope it helps, we will give it a work out soon.


Pics are before and after.

[Bookemdanno]

I'll comment, since I did this mod last summer. We pulled into Vicksburg, MS yesterday around 3 pm and the inside was showing to be 97 degrees. We had all the blackout shades drawn and some of the windows had the metal insulator sheets (Reflectix??)cut to the windows. Had 50 Amp service, so both A/C's were running immediately upon plugging in. We (in-laws, DW, and kiddos) hung out for about 90 mins...the adults were drinking very cold beer from the cooler (just a couple...I promise). We went to dinner at the Cracker Barrel and when we came back at about 6:15 pm, the a/c in the living area showed to be at 82 degrees and the bedroom showed to be at 77 degrees. Once bedtime came around, it was very comfortable in the RV for all. Just my 2 cents...I can't say for sure that this mod helped, but I like to think so.

[Griswald One]

After two days of Monsoon Rains in Myrtle Beach I discovered that this Mod had resulted in a leak inside my A/C unit. I had a fairly significant amount of water collect within my interior cover and we could actually hear the water dripping inside the unit. For the life of me I could not figure out the problem as the water appeared to be coming from a source above the roof line and was collecting in the A/C units metal base plate before dripping down. The foam roof seal appeared to be dry and the water was only found on the intake side of the unit.

After the first night I had blamed it on condensation since the unit had run for four consecutive days at well over 90 degrees. On the second night I decided the rainfall and water in the unit could not be a coincidence and I went hunting.

It appears that the reflectix on the box had resulted in one of the shrouds bolts not seating properly and water was making it under the washer and in through the bolt hole. When I took the shroud off there was obvious moisture in and around one of the front bolt holes. I did a quick test, blowing through the hole, to confirm that it went through into the A/C unit. There was a very clear impression in the reflectix where the plastic shroud is supposed to seat so I have cut out that section and tightened everything up. Hopefully this will resolve my leak, but I think my next roof maintenance will include some Dicor around those four bolts in the Shroud as well.

All the Best!

[denn888]

Originally Posted by Campbellizer

I plugged mine into shore power this morning and let it run till the inside temp was 70 degrees. Probably ran an hour to get there. Then I climbed on the roof and pulled the a/c cowling. I did in fact see condensation on the back of the box that everybody is insulating. That fact alone tells me that insulation in that area might help.



I felt all around the box while the unit was running and it was noticeably cooler right around where the fan mounts and I (not coincidentally) found the condensation. However that was the only place. So, i put some Reflectix in that area only. Basically the whole back side where the fan mounts and nowhere else. I also went ahead and put aluminum tape on all the box seams and put the foam insulation over the low pressure line since I was already up there.

I've also noticed that there is some leakage between the ducts and the ceiling around then vents. In other words, leaking back into the ceiling. So I used aluminum tape to seal up the area between the duck and the ceiling. The vents themselves have a round plastic piece that extends upward and is supposed to seal all that up. They do not seal completely and appear to block some of the airflow too (since some of mine were nearly touching the top of the duct). Two of my ducts had very little air flow coming out (with one of them being in the bedroom ). I snapped the round piece off of the vents and reinstalled them. I can definitely feel an increase in airflow from those two vents now.

It's 91 degrees today with a real feel of 109 degrees right now. My unit is sitting in the full sun and the temp inside is holding steady at 70 degrees. It's even cycled off a time or two. In the past I've had a difficult time holding 70 degrees inside when parked in full sun. It will usually drift up to 74 -75 degrees on days like this.

I'm just going to let it run to see how it does today. I'll report back later.

Just curious, when you removed that collar did you lose flow in any of your other vents? I have the coleman-mach 15. My one duct has 3 vents on curb side that feeds the bathroom (coldest spot in trailer ) then 2 in the bunkhouse. The first vent in bunkhouse barely had flow due to collar sticking up so high into the duct. I unsnapped the collar off and got great airflow coming out of both vents in the bunkhouse. I checked the flow in the bathroom and lost a lot of airflow. I had the DW 😚 cut about 1/2 inch off the collar, restored good airflow back to bathroom plus the bunkhouse still has better airflow, I believe I needed some baffling to balance the airflow in the ducts...My driver side ducts 3 vents flow well in the living room/kitchen to bedroom, no need to mess with the collars on that side

[Campbellizer]

Originally Posted by denn888

Just curious, when you removed that collar did you lose flow in any of your other vents? I have the coleman-mach 15. My one duct has 3 vents on curb side that feeds the bathroom (coldest spot in trailer ) then 2 in the bunkhouse. The first vent in bunkhouse barely had flow due to collar sticking up so high into the duct. I unsnapped the collar off and got great airflow coming out of both vents in the bunkhouse. I checked the flow in the bathroom and lost a lot of airflow. I had the DW 😚 cut about 1/2 inch off the collar, restored good airflow back to bathroom plus the bunkhouse still has better airflow, I believe I needed some baffling to balance the airflow in the ducts...My driver side ducts 3 vents flow well in the living room/kitchen to bedroom, no need to mess with the collars on that side

No, I can't discern any noticeable difference in flow from the other vents after removing the collars. But my duct work is relatively straight running. The collars seemed to make the vents flow progressively worse the further away I got from the unit.

Now I do "throttle" the living room vents back at night so that my bedroom vent has more flow. In fact, I usually completely shut my ducted living room vents at night so ALL of the ducted air flow ends up in the bedroom. This works well as the biggest volume of air comes directly out of the ceiling mounted unit and I NEVER close the vents for it. This seems to strike the best balance in keeping the bedroom and living room cool at night.