A/C units - how cool Dow they get?

[Exilenla]

Originally Posted by Lt Keefer

RVs do not have the same insulation values as stick built homes so cooling from the 100s to 80s sounds about right. We've added blackout curtains to the windows as well as putting those pillows things in the overhead vents. I also added insulation between the layers of the bathroom skylight. That thing was light a heat lamp on hot summer days. Our coach is a lot more comfortable on 100 plus days now than it was from the factory but the A/C units tend to run most of the day.

Couple of quick questions for ya Lt.
“....those pillow things in the overhead vents” what are the pillow things?
What layers of the skylight? Not sure what layers you mean bud

[Oneilkeys]

On Amazon.

[Exilenla]

Originally Posted by Long & Winding road

They are correct .... The best thing you can do is "heat management".

Dont let the inside get above 80 deg if you can help it. Takes a long time to suck the heat out of the furniture and inside walls (esp if in full sun).

Use the refective bubble in all the windows that you can.... esp the side that is facing the sun.

I had "clear" (Well 15% so almost clear) ceramic window tint installled on ALL my windows (the factory tint is just color.... no UV rejection - so this ceramic is a awesome). This helped greatly and we are not sitting in the dark with the windows covered with reflective bubbles all the time.

Check your return air duct inside the AC unit. Mine was sucking hot air on the cold side (do a search on this - lots of threads on this subject). Plus I insulated the AC unit on the roof (plus AC lines) and moved my Thermister probe up about two inches.

I went from 65 deg output temp (at ac dump vents and roof vents) to 45 deg!!! It blows that temp no matter what the outside temp is. So I can get in the mid to low 70's (95 deg outside) and even high 60's if its only like 88 deg (or less) outside!!

So reject heat first then make your exsisting AC unit work better before you add any more AC units. You might be pleased like I was (but My RV is only 27 foot so one AC works fine for me).

Outstanding and easy enough to do for me..... being an insulator 👏🏻👏🏻😂

[Beau388]

Originally Posted by Exilenla

These are all great replies and I’m working. My way through all of them to compare our current set up. One thing I’m trying to do right away is get the actual circular vents off to see if the duct work is leaking. Some of the vents are hardly blowing (compared to others). I didn’t want to just force them off - is there a knack to it?

Thanks ����

There is a snap-on beauty ring that covers the four screws that hold the circular vents to the ceiling. It the same as the dash vents.

[DinoC41]

Originally Posted by Exilenla

Fairly new to this whole Rv’n thing... and our Miramar has two A/C units one in the main coach area, and one in the rear sleeping area.

We had it out in AZ again at the weekend 100F+ outdoors and the units were in full blast but the inside temp never got below the high 80’s ��

Does that sound normal???

Worth noting the unit in the rear did manage to cool the rear bedroom
Area to a comfortable temp.

Surely these units should get the coach down into the 70’s.... ����*♂️

Input / thought would be greatly appreciated

Please check out this Youtube video...I think your questions and concerns will be answered

https://youtu.be/rxCljBVi8DU

[sanapier]

We have an '18 Hurricane 35M. Haven't read all 25 replies but both units are vented together and are both 13.5k. Just got home from central AZ and had the same issue. I believe I will eventually install a 15k on the living area. Just not sure that a 15k might overpower the 13.k due to the combined vents, front and back.

[powerboatr]

Originally Posted by sanapier

We have an '18 Hurricane 35M. Haven't read all 25 replies but both units are vented together and are both 13.5k. Just got home from central AZ and had the same issue. I believe I will eventually install a 15k on the living area. Just not sure that a 15k might overpower the 13.k due to the combined vents, front and back.

nope the unit will not over power. its just removing more heat than the 13k unit.

[sanapier]

Originally Posted by powerboatr

nope the unit will not over power. its just removing more heat than the 13k unit.

Thanks powerboatr!

[Beau388]

Originally Posted by sanapier

We have an '18 Hurricane 35M. Haven't read all 25 replies but both units are vented together and are both 13.5k. Just got home from central AZ and had the same issue. I believe I will eventually install a 15k on the living area. Just not sure that a 15k might overpower the 13.k due to the combined vents, front and back.

Cheaper to put up a Magna Shade. Changing to a 15,000 btu A/C up front will add 5.6% more cooling capacity.

[Long & Winding road]

Yeah, rejecting the heat from the outside will make your AC work much better. Blocking windows, ceramic tint, vent pillows, seal cracks and gaps everywhere you can. Keep engine heat out of cockpit area.

It all adds up.

I think I can get 25 deg cooler than outside temp if the RV is not sitting in the sun all day (with AC off). I will have to test it this summer.... it just not getting hot.

[cladouce]

Hello,
I just received a 2018 Thor 24 foot C Class on a Sprinter frame. The AC is a 13500 BTU and the ceiling has round vents along each side. 80% of the cool air come directly out of the AC unit and 20 % of the air come out of round vents but only on one side. I find the total quantity of air low . I had it taken in to a RV repair center and the mechanic indicated the AC is not strong enough to push enough air trough the all the air vents. This seems odd to me.

Does anyone have some experience with this model?

[Long & Winding road]

Sounds like you have some blockage for use on the one side. I bet they find leaks around the AC units hot and cold side + gaps that can be taped up to improve air flow.

Did you try closing the vents on the AC cover its self to force more cooling though the vents? If you have all of the AC cover vents open it will limit what can be pushed down stream.

I start out with one or two of my "dump vents" open on the cover then after about 30 min I will close one or all of them to force the air though the round ceiling vents. Works pretty well in my RV but I have the 15000 BTU unit and 27 foot long RV.

[cladouce]

thks, will try to find the leaks.

[BSexton]

Originally Posted by cladouce

Hello,
I just received a 2018 Thor 24 foot C Class on a Sprinter frame. The AC is a 13500 BTU and the ceiling has round vents along each side. 80% of the cool air come directly out of the AC unit and 20 % of the air come out of round vents but only on one side. I find the total quantity of air low . I had it taken in to a RV repair center and the mechanic indicated the AC is not strong enough to push enough air trough the all the air vents. This seems odd to me.

Does anyone have some experience with this model?

The first thing I would do to see if you have a problem is to close the vents on the AC unit itself and see if you have air coming out both sides.


I also have noticed that one side of the rig gets more air out of the vents than the other side. (For the life of me, I can't remember which side right now). When I was going through my process of sealing up the ends of the channels cut in to the Styrofoam, taping up the leaks in the AC unit and adding another vent to the AC cover, I also noticed that one side of the unit got much more air than the other. I ran a scope down the channels to see if there was any blockage. I couldn't find anything that would cause such a big discrepancy between the two sides.


Then, one afternoon, I was looking up into the AC with the cover off. I noticed that the fan that was moving the air was a squirrel cage fan. That type of fan pushes air out all the way around it. The fan in surrounded my a shroud that push the air down in to the RV and in to the vents. But, it doesn't push it down in a straight line. Because of the physics of the squirrel cage fan, it would push the air more to one side of the RV than the other. It matched what I was seeing. The side where the air was being pushed to because of the squirrel fan had more air flow than the other one.


So, I just chalked it up the way the squirrel fan pushed air in to the coach.

[Long & Winding road]

Well on my Axis both sides are about equal with air flow. Sure the last vent in the bedroom does not have much air flow as the first one in the kitchen or hallway area.... but its not dramatic.

Perhaps you have a air leak around the fan shroud? I have not looked at my lately but perhaps you can remove the fan and inspect this area then add some tape as needed?

Did you block of the ends of each duct? Once I did that my air flow increased almost 2 fold. The front part of the duct just dump into the bulkhead in the cockpit area. Total waste of good air. I insulated the bulkhead and over the cockpit area to reject heat.

I also modified the last vent on each end of the duct (so 4 vents) to improve the airflow. All of these mods added up and worked wonders.

[Long & Winding road]

I also insulated the A pillers to help with heat and sound.

I took some water pipe foam insulation and taped some frost king to it. I left it kinda loose so it would expand in the A piller location and absorb sound + reject heat (and cold).

[cladouce]

Thanks you all for all the help. I followed all recommendations but disappointed with the results till I noticed that the cold AC air was coming out of the Air filter and going in the unit by the vents. It should be the opposite , the hot air should enter the unit via the filter and the cold air exit via the vents.

I removed the grill and turn it around 180 degrees. Air volume increased in vents and ducts. Eureka!