Air Conditioning in my Bighorn. Is this as good as it gets?

Peteandsharon

Well-known member
I know we've had many threads about this A/C issue in some of the Heartland trailers. This is our second season with the Bighorn and frankly the very first time that our A/C got challenged in the least. Last year our big trip was to South Dakota and the furnace came into play. The A/C didn't. Our earlier trip this year was to northern Wisconsin with temps in the upper 70's. Again, A/C was not an issue. The past few days we have been out at Illinois Beach State Park and the BH was out in the open with no trees, temps around 83 and relatively high humidity. What I found is that by mid afternoon I couldn't get the inside temp to get below about 78 degrees. Without cranking up a good fan it was actually a bit uncomfortable in the rig. I'm asking about this because I hesitate to think what it would be like if the temps were in the mid 90's instead of the mid 80's. After reading last year about the issues that others were having, I built my own "tent" contraption in the A/C compartment similar to the one that others have built. I also added a bedroom A/C but with a 30 amp park connection, I couldn't run both A/C's.

So...... my question to some of you is whether this performance is "typical" of what you have been seeing. My BH has the standard 15 K BTU Dometic A/C. I know that with both A/C's cranking I would not have this issue but you don't always have 50 amp service. Even though the rig is unprotected in the open sun, should I be having trouble getting it down below 78. Should I be able to squeak some better performance out of this unit or is this typical of what you guys have been getting on one A/C?

Thanks, Pete
 

Tom of Ypsi

Well-known member
Pete & Sharon,

Your temps should get below what you are saying. We are on 30 amp, no shade and the last couple of days it has been in the upper 80's in SE Michigan. I have the temp set at 73 and it was down to 74 in the coach. I do bbq outside, minimal cooking inside as this does create a lot of heat, I keep the blinds closed on the sunny side of the coach and open them up as the sun moves. I also have my overhead fan on medium going counter clockwise. Hope this helps a little.
 

escs36

Member
i camp where it is a 100 plus so the a/c is hyper critical. i have not tried this yet, but i have considered it. in the event of only a 30 amp hook-up and only 1 a/c, i would block off some of the ducted vents. i have a cyclone 3912 by the way. i will block the vents to the garage area, the "attic" above the garage, the bathroom vent, and the bedroom vent. of course close all doors and concentrate the cold air to the living quarters and the kitchen. i find that the 15K a/c works barely good enough in 100 degrees. i fire the a/c's before its too late. when its that hot the coach is only comfortable, not cold like you expect. if i run the second 13.5K a/c which is in the bedroom, the bedroom gets freezing. my solution is to run a small fan pushing the cold from the bedroom to the living quarters. seems to help. the garage area always seems to be a bit warmer.

my thought is that you may need to have your a/c serviced.
 

2010augusta

Well-known member
I have been camping in South Texas for 5 Weeks now an 100+ almost every day. I have the main A/C fan on high AND the down draft vent OPEN, no tent for me. With the bed/bathroom doors closed it will easily keep the living room at 78 degree where we have the thermostat set, any cooler and I need a blanket:p. I have also found it is more confortable to leave the fan set to run (on high) all the time. I only use the bedroom a/c to cool that area while we are sleeping. I keep all windows closed and the blinds down all the time. We have dual-pane windows, and that helps a lot.
 

tmcran

Well-known member
In Texas temps 95-100. Keep A/C about 75 on high speed. As long as I keep it running in the AM it will maintain comfortable temp. I do use a small fan to move more air as the ceiling fan is about useless. Have the 15K unit. Did the tent and it does help.
 

Bob&Patty

Founders of SoCal Chapter
I think that we all forget that these coachs only have 2" walls. I think the R value is 8. This isnt you home that has at least an R value of 13. Start your A/C early in the day to "condition" the inside of the coach. Close all the blinds to block as much heat as possible.

Pete, does your coach have dual pain windows?

We camped 3 weeks ago in 107* temps and high humidity. The single 15K did OK. We used a small fan to move air. After the sun started going down you could hang meat in the coach.

I did do the "tent in a vent" and also sealed all the duct work. It made a big difference in the air flow. Bob:D
 

Ray LeTourneau

Senior Member - Past Moderator
Pete, like the others, our a/c does a great job. We have the bedroom a/c but have not had the need for it yet. in the low 90's here in central WI and we can easily maintain 75 inside. Like Tom, we cook outside and keep the blinds and shades down as needed.
How is your air flow? Do you get a good volume of air from the vents? IF yes, try and check the air temperature coming from a vent close to the a/c. It shoud be in the 40-45 degree range. If your air flow is weak, you have to determine what's blocking the flow. If it were possible, I would like to actually give you some help in improving the flow cause it's real hard to explain the techniques. There's more to it than just the tent. You come up to Wisc Rapids and we'll git er done.
 

2010augusta

Well-known member
Another thought is to make sure the filter media is clean, we move a lot of air and I have to clean ours every other week. Run the fan on HIGH speed, it is noisy, but necessary to keep things from freezing up.
 

rick_h

Active Member
It could also be that the coils inside the AC are dirty - this will drastically affect heat transfer from the inside of the coach to the outside. If in doubt have an AC tech check it out. They can put gauges on to check if things are working properly.
 

TXBobcat

Fulltime
My A/C has always been working pretty well until the other day. It seemed like it was not working very well. It has been keeping almost a 20* differential.

I opened the down draft vent and the air was very cold. Took the cover off and some of the tape used to smooth out the duct had came loose and dropped down. One corner about the size of the end of a cigarette package was open into the attic.

I bought some of the aluminum tape and a can of foam. I sprayed the foam into all the cracks I could find around the duct. I then used the aluminum tape to smooth the duct openings. I went to Ace hardware and bought a small piece of thin aluminum that I can bend by hand.

I am going to take some velcro and put on the aluminum and some on the opening, then put the TENT in place and move it around to get the best flow. If I have a problem and need to open the direct down flow I can remove the TENT..

You might check the openings into the ducts.

BC
 

kakampers

Past Heartland Ambassador
Are you leaving the unit run during the night to maintain temps?

We've discovered that maintaining a temp is much easier than trying to get down to it...DH likes it like a meat locker (72 degrees), and we've had no trouble keeping it down to that, even in 90+ temps...however, when we move, and the temps in the coach rise up, sometimes into the 80's, it takes a long time to get it back down. Especially when we're on 30 amps and can only use the one, main unit.
 

trdeal

Past North Carolina Chapter Leader
PeteandSharon, If you have a remote control with your ac try using the" I feel "setting.We have found that this makes a huge difference in the temperature in the coach.
 

Oldlthrneck

Just an Old Jarhead
We had a bit of a problem during June, when the temps were in the high 90s. So I had a second AC installed in the bedroom. Opted for the 15k. Then I blocked the bedroom vents and that really picked up the airflow from the main AC unit. You can stand under the vents in the kitchen and it will blow your hair. We have no issues keeping our coach cool at all. Like has been mentioned, the walls are not that heavily insulated. When the temps got above the mid 90s it was harder to keep the it in the comfortable range with only the one AC. Now it is like a meat locker, just the way us northern boys like it. :D
 

Peteandsharon

Well-known member
Thanks for all the good replies, guys. To answer some of your questions, yes we keep it going all the time. Over night it gets down to about 67 in the rig......... very nice. However, invariably by about 2:00 in the afternoon, it has climbed to about 77-78. No cooking/oven activity can be blamed. We keep the day shades down but not necessarily the night shades. Maybe I'll do that. I'll check the air filter but I have a hard time believing that is the issue since it just hasn't been used that much. Same answer for dirty coils etc.

I do believe that air flow is the main problem. It certainly does not come out the vents like my old travel trailer. Airflow is weak pretty much everywhere. I think that is the issue rather than the A/C itself. My tent may have made some difference but it was not significant. I also got inside and tried to seal any potential air leaks, again like many of you have also done. I think tonight I need to get back under the hood and look.

Ray, I'd love to take you up on your offer. Unfortunately, my vacation time is coming to a close and we may not get her out again until a brief fall excursion. I'll take another look at potential air blockage and see if there is something obvious going on here. Thanks again, guys.
 

Peteandsharon

Well-known member
Well, this afternoon I pulled down the grill and air filter. Everything looked alright, as I had left it. Where I had sealed air leaks they still looked sealed. The tent was still in place and looked fine. The air filter did have a surprising amount of dust on it for as little as it has been used. So I cleaned it, let it dry and put it back in. I came back a few hours later and it had taken the temp down to about 70. Of course...... a weather front had come in and the afternoon was rainy with no sun. So I was comparing apples to oranges and I really don't know if I fixed anything It needed to be cleaned regardless. Next step is to get a good small mirror and start looking down the ducting for any blockage.
 

Bob&Patty

Founders of SoCal Chapter
Pete, today I finished doing the "tent in a vent". Take down the potty room lower fan vent cover, 4 screws, and look at the end of the duct. The tape to seal it was all but gone on mine. I stuck 2" hard foam I had left over from insulating under the BR floor and put it in the end and taped it shut. It made a difference in the air flow on that side. (door side)

I also checked which way the duct work runs by putting a towel in the ducts to shut off air flow so that I knew what duct went to what register.

I did my "tent" mod a little different than Tims. I used 2 pieces of aluminum sheet metal. I did take down the inside mounting plate to do this. I cut them to fit under the ducts where they enter the plenum. I also cut them to fill in the "V" shaped area going to the seal for the return air chamber. Because of the way the air enters the plenum, I bent the end on the left side piece up at an
angle to force air into the left side ducts. (off door side) Boy did that make a difference in the air flow to the BR. It blew my hair off when I went in to check it. On mine the right side duct leaves the plenum, goes to a "T", then goes to the potty room and then along the right side (door side) roof to 2 registers. It seemed a little better


BTW, did you tape off everything in the return air and the plenum side?? Every nook and cranny. Any place that can leak air or pressure into the roof cavity?? I did that 1st and it did make a difference. Make sure you remove the registers and retape all the register opening between the ducts and the ceiling material.

Bob:D
 
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jmgratz

Original Owners Club Member
As a rule most Campgrounds are dusty places and the filter in the RV ACs seems to need cleaning more frequently than the home AC. It is amazing how much a dirty filter can affect the cooling.
 

KENNY COCHRAN

MCNEESE STATE COWBOYS #1
We have a 3670rl with 2 ac units. We live in south louisiana with temps in the 90's and humidity over 100%. (yes it does get over 100% to me!!) i have to say this rv is well insulated compared to our past rv, forest river, sierra. We only ran the 15 btu unit this weekend in the dump mode in the living room. Turned it off at night to get more air to the bedroom. In our sierra, we had to run both units to stay cool. I did put 1" solid foam insulation in the 3 bedroom windows which cuts down noise and also a lot of the heat from the sun. Also put foam insulation in the top part of the big rear window.
Can't complain about the ac in the bighorn!! Love it.
 

SmokeyBare

Well-known member
Bob covered it pretty well in his post # 16... I'll just add a few more ideas.

I removed each ceiling vent so I could re-seal the often broken duct tape around these openings. I found area's where the A/C air could flow back into the attic.

I also blocked the duct just past the last ceiling vent on each duct run. I was surprised the duct work ran past these... not trusting the duct was sealed well enough on the ends... I installed a block.

I also used duct tape to seal the return air side of the A/C. I found several holes and gaps where air could be pulled from the attic... I wanted the A/C to work less by only cooling the air already conditioned.

When we get lucky... our door side faces the north... which gives us quite a bit less radiant heat getting into the RV.

Good Luck !
 
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