AC in hot weather

[bsmith0404]

I know a few people have commented on AC problems getting their camper cooled down in hot weather. We've never really had a problem before, but haven't been above 90* much. Last night we stopped in Gila Bend,AZ. Temps were 104*. Got set up and started the AC. It took the bedroom AC about 2 hours before it got down to temp, about 3.5 hours for the main AC. We have the thermostat set for 71.

[Javi]

I know that I'm a good bit strange in many ways... don't need or even want heated steering wheels, leather interiors, cooled seats or carpeted floors.... so this won't come as a big surprise... we generally keep our thermostat set at 75 degrees in the summer... but we also have two 15K units and even in 100+ temps without a tree within 1000 yards the Cougar will hit 75 degrees and begin to cycle the compressors within the hour starting from scratch... I do open the rapid cool ports on both units and turn on the MaxxFan for cool down...

What size units y'all running?

[Outback 325BH]

I have a 38' TT. When I bought it I had two air conditioners: the main 15k one a little forward of center and the master bedroom 13.5k unit up front. These two did OK for those rooms, however the bunkhouse would stay hot. The duct run was just too far from the main unit to be useful.

I then installed a third ac for the bunkhouse. That was a game changer. It doesn't matter how hot it is outside, I can cool down to any temperature I want in short order.


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[msubobcats]

We have just one 15k ac in ours and last year were in 105* with very little shade and ours struggled mightily to keep it even close to comfortable.
HOT weather, you had better have two ac units...

[dcg9381]

It was in the 90s this weekend, 3 kids going in and out. 2 AC units held us at about 77 degrees in the living room.

I did notice that the tape at some of the vents had started to come un-taped and make noise.. The other side effect is that it starts to cool space above the ceiling, so that's on my to-do list.

If you have a ducted AC system, make sure you drop the AC plenum and check the entry points to the vents - often the issue is there.

[bsmith0404]

Originally Posted by Javi

I know that I'm a good bit strange in many ways... don't need or even want heated steering wheels, leather interiors, cooled seats or carpeted floors.... so this won't come as a big surprise... we generally keep our thermostat set at 75 degrees in the summer... but we also have two 15K units and even in 100+ temps without a tree within 1000 yards the Cougar will hit 75 degrees and begin to cycle the compressors within the hour starting from scratch... I do open the rapid cool ports on both units and turn on the MaxxFan for cool down...

What size units y'all running?

Both are 15k units. It probably would have helped if I had thought to open the vents and run the fans to evacuate heat, and if the kids knew how to close a door! I was actually pretty happy with the performance of the AC with the sun beating down on us with triple digits. It was comfortable fairly quickly, just getting down to 71 took a bit of time. The main area would have cooled quicker if I had opened the bedroom door and gave the entire 40' the benefit of 2 AC units, but I was being selfish since the kids kept opening the door. I felt it was a good time to relax and escape the heat after a 400+ mile drive.

[Rick52]

I live in southern calif, so if it's over a hundred outside, 78 feels great inside. 71 seems a bit overkill, but if you can get there, great..... I sweat in a snowstorm, so would be ok with me, however, my wife would be a popsickle. She has a sweater on in the middle of summer...

[Desert185]

The indoor/outdoor temperature delta for our 326SRX with 15K and 13.5K AC's seems to hover around 15 degrees, 20 if we're lucky. Can't believe it, but it looks like we're going to Vegas for four days on July 1st (family thing). 50a service at the Oasis (Passport America 50% off kicks in on July 1), so we'll see what the current result is. At least it's a dry heat...

Sushi at Musashi with the son and granddaughter will help compensate.

[JRTJH]

I was always taught that the "temperature Delta" was the difference between the "intake temperature at the unit" and the "output temperature to the ducts". A tD of 15 degrees would, when the unit is first started mean a much hotter output than you'd get when the trailer is at "normal" temperatures.

As an example, after towing in the desert, the interior temperature of the trailer may be 140F. So a tD of 15 degrees would mean the output air temp might be 125F. as the trailer reaches 125F, the input air would be 125 and the output would be 110. As the trailer cools, the input temperature would keep going down as would the output temperature. Finally, once the trailer reaches 75F, a tD of 15 would give you an output temperature of around 60F.

The outside temperature is a factor, but more related to insulation properties of the trailer roof and location (shade vs direct sunlight).

At least that's the way I understand the "air conditioner unit limitations" between intake air temperature and output temperature.

At any rate, as you say, being with the grandbaby makes it all worthwhile even if you have to sweat a little when you first get there......

[rickhz]

Originally Posted by bsmith0404

We have the thermostat set for 71.

I do not know anyone who lives in the hot parts of AZ that keeps their home A/C that low in the summer let alone their RV.


This time of year we keep our house at 78. If we try to go any cooler, the A/C simply cannot keep up, and it actually gets hotter in the house. On the hottest days, like those that are coming up this week, the A/C is usually at 79 - 80. That feels VERY cool when coming in from 110+.

Ceiling fans help keep air moving over your skin which, in this dry, dry climate encourages evaporation of sweat which makes you feel cooler. We have ceiling fans in our house, and in the RV.

[xrated]

Originally Posted by JRTJH

I was always taught that the "temperature Delta" was the difference between the "intake temperature at the unit" and the "output temperature to the ducts". A tD of 15 degrees would, when the unit is first started mean a much hotter output than you'd get when the trailer is at "normal" temperatures.

As an example, after towing in the desert, the interior temperature of the trailer may be 140F. So a tD of 15 degrees would mean the output air temp might be 125F. as the trailer reaches 125F, the input air would be 125 and the output would be 110. As the trailer cools, the input temperature would keep going down as would the output temperature. Finally, once the trailer reaches 75F, a tD of 15 would give you an output temperature of around 60F.

The outside temperature is a factor, but more related to insulation properties of the trailer roof and location (shade vs direct sunlight).

At least that's the way I understand the "air conditioner unit limitations" between intake air temperature and output temperature.

At any rate, as you say, being with the grandbaby makes it all worthwhile even if you have to sweat a little when you first get there......

John, you are spot on. Outlet air temperature is a result of the inlet air temperature that the unit sees. A temperature differential of 18 to 20 degrees from the inlet to the outlet means that the A/C unit is doing a pretty damn good job.

[bsmith0404]

Originally Posted by rickhz

I do not know anyone who lives in the hot parts of AZ that keeps their home A/C that low in the summer let alone their RV.


This time of year we keep our house at 78. If we try to go any cooler, the A/C simply cannot keep up, and it actually gets hotter in the house. On the hottest days, like those that are coming up this week, the A/C is usually at 79 - 80. That feels VERY cool when coming in from 110+.

Ceiling fans help keep air moving over your skin which, in this dry, dry climate encourages evaporation of sweat which makes you feel cooler. We have ceiling fans in our house, and in the RV.

I'll admit I don't keep the house at 70, I keep it at 73 with a ceiling fan directly above my bed. Yes I have ceiling fans in pretty much every room in the house in NM as well. Since I only have one ceiling fan in the RV and it's in the living room not over my bed, I set the temp where I am comfortable for sleeping. BTW, I know we're not as hot in Southern NM as you are in AZ, but my home AC system doesn't have any problems keeping the house at 73.

[rickhz]

It's 111 right now and it's running practically 100% to keep 78-79. Feels very cool under the registers. Our unit is on the roof, no shade at all, so that affects it as well.