AC open windows

[Steve S]

Hi guys/gals, when you have the cubes cranked do you leave a window open or keep them all closed?

[SAD]

Dawt10characters

[Javi]

Originally Posted by Steve S

Hi guys/gals, when you have the cubes cranked do you leave a window open or keep them all closed?

Windows closed, vents closed, doors closed

[Steve S]

I was thinking about leaving one open just a little, not all of them
As the AC pulls the air from the outside I'm thinking to help it move it would help to have a window open a bit.
If it recirculated the inside air like a car then the windows would be shut.

[JRTJH]

I don't think the A/C pulls any air from the outside. On some of the "older" window units there was a "fresh air vent" and when open, it pulled in a bit of "fresh outside air". The stale air was pushed out through the "leaks" around windows and doors.

Modern RV air conditioners don't have this feature and all the air that's pulled into the "warm air intake" is run through the cooling fins and discharged back into the RV ductwork or out the "chill grill"....

There's no outside air mixed with any of the air entering the A/C before it's discharged back into the RV.

Opening a window will allow for "normal ventilation" and some fresh air will enter the RV, but it will be "humid, warm air" and will detract from the A/C efficiency.

[Steve S]

Thanks John, that was very informative, I was under the impression that the air came from the outside but now that I think about it and from being on the roof it all makes sense.
Here's something else that I seem to be having a brain moment with.
When the AC is on does it just do it's own thing or does the thermostat actually do something? I've adjusted it to 55 and the air keeps going but at 85 it'll cycle?
Here's a pic.

[Javi]

Originally Posted by Steve S

Thanks John, that was very informative, I was under the impression that the air came from the outside but now that I think about it and from being on the roof it all makes sense.
Here's something else that I seem to be having a brain moment with.
When the AC is on does it just do it's own thing or does the thermostat actually do something? I've adjusted it to 55 and the air keeps going but at 85 it'll cycle?
Here's a pic.

can you push that switch over to the left one more notch to AUTO?

Set the thermostat on 70 and it should cycle correctly.

[JRTJH]

YUP, What Javi said.

The air conditioners with the "overhead controls" only have "A/C and Fan" settings of "OFF" "HI" or "LO".

The thermostat controlled A/C's have "AUTO", "HI" and "LO"

In AUTO, the fan turns off and on with the compressor (actually a few seconds before and about a minute after the compressor). On HI or LO, the fan runs continuously, even if the compressor cycles. The purpose of that feature is to allow "stale air" to be moved around the RV, hopefully to "normalize" or "average" the temperatures in different parts of the RV.

Imagine, in the bedroom at night, with the thermostat set at 72, as the outside air cools, the A/C will not cycle and the air in the bedroom will start to become humid and stale from the breathing of sleepers. With the fan being capable of running on LO or HI all night, without regard to the compressor (making the bedroom colder), the "fresher air" from the other parts of the RV are pulled into the ductwork and pushed into the bedroom, keeping it "fresher" and less humid.

We use the LO fan setting and leave the thermostat set on 68 at night. If it gets warmer, the compressor will come on to "cool the air" but even if it stays below 68, the fan will run all the time, keeping the bedroom more comfortable. During the day, when we don't want the fan noise unless we 'have to have it" we put the thermostat on AUTO and the fan cycles with the compressor and we only have to listen to it when the compressor is actually doing something to cool the RV. Otherwise, it's quiet inside.

[Steve S]

So if it's set at 70 is that like the cool setting correct?
The AC is very quite, it's not too hard to get used to, camping life right

[hankaye]

SteveS, Howdy;

When I first turn the A/C on I leave 1 window cracked a bit to help
exchange the hotter air to the cooler air like in a car/truck. After
10 or 15 minutes I close the window.
I leave my thermostat set at 88* and set the fan for Low. That way
when the compressor shuts off the air will still circulate.
After the sun rolls off the Western side of the Earth in the evenings I
generally turn the A/C off and keep the fan running all night.
We see triple digit temps here during the day and low 70's at night
so that is what works for me. Play around with it some and you'll find what works for you.
Happy experimentation!

hankaye

[Steve S]

Thanks hankaye, I found today like a few days ago that when I mess with the thermostat the AC just ends up sounding like it's struggling and then it trips the breaker but it works fine if I don't.
It seems that when the fan is running constantly then the AC works great but if it cycles then the cold air pretty much stops.
I'm pretty sure this all has to do with the low voltage coming in and the electrician will be here in the morning to run 60 amp to the shop which I'll be tagging in to.
AC is great until it stops working and then it's like a tin can in here!

[dirt33]

I searched for this type of thread as I had a similar curiosity. I have my Keystone plugged into the house power, and I have the A/C "on" all the time with the thermostat set as high as it will go. It does run often as it is over 100 here currently. I have Maxx Air II covers on the vent in the shower and the vent in the kitchen. I have read in some threads about leaving the vents open to allow fresh air into the trailer and to allow moisture/condensation to escape. However, when I see the amount of water that drains from the gutter extension throughout the day with the A/C running, I would guess it is doing a fine enough job of pulling any moisture out. Leaving the vents open is simply wasting some of the work that the A/C is doing. So, I leave all windows and vents closed now. I guess when the weather is cooler in the Fall, I may shut the A/C off and open the vents.

[Bob Landry]

Originally Posted by dirt33

I searched for this type of thread as I had a similar curiosity. I have my Keystone plugged into the house power, and I have the A/C "on" all the time with the thermostat set as high as it will go. It does run often as it is over 100 here currently. I have Maxx Air II covers on the vent in the shower and the vent in the kitchen. I have read in some threads about leaving the vents open to allow fresh air into the trailer and to allow moisture/condensation to escape. However, when I see the amount of water that drains from the gutter extension throughout the day with the A/C running, I would guess it is doing a fine enough job of pulling any moisture out. Leaving the vents open is simply wasting some of the work that the A/C is doing. So, I leave all windows and vents closed now. I guess when the weather is cooler in the Fall, I may shut the A/C off and open the vents.

Air conditioners cool by constantly recirculating the same air through the evaporator. By having a vent or window open, you are introducing air for the unit to cool that is hotter than what is recirculating normally.

As far as moisture, you are not going to remove any of it through the vent or window. That also is a function of the evaporator and the moisture it removes is what you see running off the roof and the gutter spouts in the form of condensate.

[GaryWT]

We leave the fan on and that helps with the white noise at night. We set the temp at 66 or so and let it go. The bathroom vent is usually open all the time and the door is generally open during the day unless it is really hot.

[dirt33]

OK Bob Landry, thanks for the info. It has been about a month that I have had the trailer hooked up to the house with the A/C on. I will be curious to see this month's electric bill when it arrives sometime this week. As long as this is not adding a large amount to my electric bill, I plan to keep the A/C on all summer on the highest setting, even if the trailer sits for 2-3 weeks at a time. I go out more days than not to mess around with something in the trailer, and if I had the A/C completely off, I have seen it get over 120 degrees in there. With the thermostat on the highest setting and the A/C on, it keeps the trailer right around 85 during the hottest times of the day.

Sort of a side question, as far as running the A/C all of the time. Would you consider the wear and tear on the A/C itself to be "worth it" as far as removing the moisture from the trailer and keeping the air 20-30 degrees cooler at all times? Or, would there be a certain amount of time of the trailer sitting unused (say, a few weeks) where you would say that it is not worth putting the usage on the A/C unit?

[SAD]

Dawt10characters

[Bob Landry]

Originally Posted by dirt33

OK Bob Landry, thanks for the info. It has been about a month that I have had the trailer hooked up to the house with the A/C on. I will be curious to see this month's electric bill when it arrives sometime this week. As long as this is not adding a large amount to my electric bill, I plan to keep the A/C on all summer on the highest setting, even if the trailer sits for 2-3 weeks at a time. I go out more days than not to mess around with something in the trailer, and if I had the A/C completely off, I have seen it get over 120 degrees in there. With the thermostat on the highest setting and the A/C on, it keeps the trailer right around 85 during the hottest times of the day.

Sort of a side question, as far as running the A/C all of the time. Would you consider the wear and tear on the A/C itself to be "worth it" as far as removing the moisture from the trailer and keeping the air 20-30 degrees cooler at all times? Or, would there be a certain amount of time of the trailer sitting unused (say, a few weeks) where you would say that it is not worth putting the usage on the A/C unit?

30 degrees cooler, it's not going to happen, 20, maybe. As far as "wear & tear", it's not going to suffer any more than the compressor in the AC or refrigerator in your stick& brick. The wear and tear is going to be on your wallet because these units are about as efficient as a window A/C. If I were not going to use the trailer for weeks, I would leave it off and leave a roof vet open to reduce excessive heat buildup. You can also help it by going through and making sure that the AC plenum and ducting are properly taped/sealed and that you aren't losing cold air up in the roof area.

[Javi]

When we aren't going to be using the trailer for a length of time, I open the roof vents, turn off and prop open the fridge doors. The air is off and all breakers are turned off except the main and converter so that the battery minder in the converter can do it's thing.

When we're camping I will open a roof vent while we shower or use the facilities but it is closed otherwise. The only time any window is opened is if its one of those rare Texas days when its nice out but the mosquitoes are busing and we want to enjoy the fresh air without the bugs. And we sometimes open them at night to enjoy the fresh air. But if the A/C is on they're shut.

[hankaye]

SAD, Howdy;

Originally Posted by SAD

When you start to ask yourself about "wear and tear" on RV appliances from simply being used as they are designed to be used....

Consider this..... What does someone who lives in their RV full-time do?

I've already posted mt reply and I live in mine 365, in the Southwest desert
of New Mexico. Right now we have nighttime temps in the mid-upper 60'sF
but our days still climb into the mid to upper 90'sF. Oh, and we have stifling
(for us), humidity in the 40% to 50% range, it's still Monsoon Season after all.
Normally our humidity is in single digits .... and swamp coolers rule, whole
'nother set of operating parameters.
Right now I open the windows in the morning, appreciate the breezes, then,
when the temp. and humidity climb to what I consider to be almost uncomfortable,
I'll turn on the A/C and fan, close all but 1 window (gives the warm air a
place to escape, then ...when it starts to feel cool, I shut the last window
and enjoy the cooler environment.
It's what works for me, you may find a routine that will work for yourself.
I give my A/C unit regular check-ups, remove cover, clean evaporator fins,
(we have dust issues here), add a drop of lubricant to shaft, check the seals
all that stuff. The same things stick&brick folks should be doing to their A/C
units.

hankaye

[dirt33]

Originally Posted by SAD

When you start to ask yourself about "wear and tear" on RV appliances from simply being used as they are designed to be used....

Consider this..... What does someone who lives in their RV full-time do?

Good point, thank you.