Seriously 'though, detriment to what? Night shades keep out light, but if they block the air flow, they won't do any good. Assuming the outside temperature/humidity is lower than inside, ventilation from the outside will help. If it's hot and humid outside (more so than inside), it probably won't help except for the feeling of air movement over your body. Six of one; half a dozen of the other.
That was a trick question, right?
No. being easy to pass out or have seizures high humdity and heat as an additional factor. I was serious. Lets not deflect from the original question as it was indeed a good one. I will back off and search further with my questionable question. My apologies to the original writer.
1: Power cooling (Air Conditioning)
3: Ventelation (NOTE 1 and 3 confilct in many cases)
Now, Southern engineering says you build nice THICK stone walls that soak up the heat in the day (keeping it from the house) and release it at night (Keepin said house warm cause nights get COLD in the dessert) However you are not in a built in place house,,,, You are in a RV, much thinner (But insulated, one hopes) walls.
So, it's either AC or Ventelation during the day, heat at night and SHADE if you can arrange it. Shade can be natural or artifical
Best shade: An array of SOLAR panels (Hooked to an inverter, powering the AC of course)
Using awnings help keep the direct sun light from entering the RV and heating the inside of the coach (and fading furniture).
Sunscreen on the front windshield and driver/passenger side windows helps keep out heat as it blocks 80-90 percent of the UV rays from the sun. I was amazed how much heat ours blocked. There are several manufacturers and we think this is an excellent investment.
I don't usually run the A/C when out for the day but I set the automatic fan vents to come on when the inside of the coach gets to be about 85-90 degrees. If you don't have the automatic fan vents, you may want to open any ceiling vents to let the hot air escape (hot air rises).
I don't pull the shades down with the windows open due to moisture and/or dirt that could get on the shades.
Geez, my "No, you can't" response was obviously meant in jest. I'm sorry if you took it any other way.
My answer to you was a serious one, and there are several ways to keep things cool and comfortable; many of which have been discussed previously. Awnings, parking in shade, window tinting, interior shades. A dehumidifier may help if you don't have a/c (an air conditioner IS a dehumidifier), but it does nothing to reduce the actual temp. inside. Start your a/c early in the morning so it isn't playing 'catch up' all day. Seal overhead vents/skylights with insulated pads. I'm sure there are other things you can do too.
You do NOT want a de-humidifier in the southwest. Air conditioners really don't work all that great in hot, dry areas. We use swamp coolers, great big fans that blow air thru wet pads to add moisture. Sounds crazy to folks who live in humid areas, but that's what works in these areas. We actually had to move out of our 5th wheel during the summers in Death Valley because the A/C couldn't keep up with the heat....figure cooling 20 degrees below the outside temperature if you're lucky.
Not much help but shade, window awnings, and a humidifier (NOT a DE-humidifier) will help.
I've found that making sure the awning is facing the Sun and let the awning take the brunt of the heat. Also, I keep both of my bedroom windowns with reflective insulation paper between the shade and the glass. I also place an insulation paper in the window by the coach in my slideout. This adds lots of reflection. One could also be installed in the table window. Not only do they reflect the heat, but they also help keep the cool in. And by all means if you have the windshild insulation, use it and then close the drapes. If it's 105 O/S, you just Might (?), Might get it down into the 70's.U Using a small circulating fan near the bedroom blowing into the kitchen will also help should you keep the bedroom A/C on. Best I can offer, unless you head North and high altitudes.
We've spent many a night in hot southern AZ weather. We bought an electric 3 speed fan that ossicilates within the coach. Helps to have air blowing on you. Cool it down inside before it gets too hot with your AC if you can. Once all the floors counters etc. get hot, it is much harder to get them any cooler. I keep the window shades closed and that silver plastic bubbled stuff (purchased at Camping World or any big Home Improvement stores )works well as an insulator. I cut it to fit the windows. Having dual pane windows was a big improvement I noticed from one rig to the newer one. Window awnings helped to cut down the sun.
As Wendy says you can't expect the rig to cool to much more than 20 degrees cooler insde than out with even the most ideal conditions. We try to move north for the sumer.
One thing I forgot to add about Air Conditioning (And why it's not all that great in 100+ weather)
The "quick test" for AC is 30 degree drop. 100-30 = 70, So if it's 110 in the shade, you won't get much below 80 AT THE OUTLET, hotter in the rig They used to make "pre-coolers" (2 stage AC units) don't ,now how good those are as I've only seen pictures, and that was a while ago