Dual A/C's - Trying to Keep Cool In Texas

[charlie.leverett]

I just purchased the Montana 3750 and here in my area (TX) the temp has been in the 100 + range for some time, it has dual A/C's but i still can only get the inside temp down to mid 80's during the hotter periods of each day, any suggestion or is something wrong?



(Moderator's Note: This and following 3 posts have been moved from New Member Welcome to Keystone Questions)

[LarryL]

I think A/C will only cool 10 degrees below outside temp so your like to
to have 80 degrees.
if you go outside for a few minites and go back inside it will feel much
cooler:rofl:

[hankpage]

Welcome to the forum. :wave: I'm sorry to say it but a 20° differential in a trailer without shade is just about normal. You can try getting it cooler in the early morning and hope it holds temp a little better. Keep cool, Hank

[Me.Bikes.Dogs]

If the temperature difference between the intake air and outflow is 15 degrees or better, your units are doing the best they can. Finding a shady camping spot is about the best thing you can do now.

If you search this board, you'll also find some threads on retaping your A/C ducts. That can help a little. Makes the existing units a little more efficient.

[DocData757]

Using fans in addition to the AC will help a lot.

[Rock7]

I got insulation, From Camping World last year. Cut it to fit the windows and helped a lot in Az last summer.
It looks like aluminum with ins. sandwiched and sewn like a quilt. Cut to fit windows,and it stops a lot of sun. and heat.
Works well in the cold also.
They carry 2 different size rolls. Larger one fits big windows in Slide-out and across the back.
I think I had to buy two large rolls, and a small one.
Measure the windows,footage is on rolls

[fivergeezer]

I have a similar problem in Florida's heat and sunshine. I've used the foil window treatment but my wife doesn't like the dark cave-like atmosphere. I'm thinking window awnings and slide toppers, but finances won't allow this until next spring.

[Festus2]

fivergeezer -
I remember reading an article about slide toppers and their effectiveness in keeping the RV's interior cooler in hot weather. If my memory serves me correctly - which may be asking a lot) - slide toppers do little, if anything, to keep the inside temperature down. Unfortunately, I can't give you any factual reference but perhaps others can. If you are going to purchase toppers for the sole purpose of keeping the inside temps down, it might be worthwhile to do some research to find out if, in fact, they actually do work this way.

[Ron]

fivergeezer -
I remember reading an article about slide toppers and their effectiveness in keeping the RV's interior cooler in hot weather. If my memory serves me correctly - which may be asking a lot) - slide toppers do little, if anything, to keep the inside temperature down. Unfortunately, I can't give you any factual reference but perhaps others can. If you are going to purchase toppers for the sole purpose of keeping the inside temps down, it might be worthwhile to do some research to find out if, in fact, they actually do work this way.

Festus: In my opnion the slide toppers do help keep the interior cooler. I have felt the sidewalls in the slide in the direct sunlight, then the ceiling of the slide and there is definetly a noticible difference in temperature. Just my 2 cent worth. Happy Cool Campin.................Ron

[Smitty43]

I too, have my Alpine 3200RL in west Texas. We have already had ays of over 100 degrees. I bought the quilted insulation that was talked about in one ove the above post from Lowe's for $42.00 for the 4 ft. x 25 ft. roll. Cut them to fit all the windows and have no problem getting my RV down to 71 degrees. It sure made a big differance in the cooling. The local RV store wanted $75.00 for the same stuff.---Smitty

[byrdr1]

The foil type insulation is great. We used it one summer on my pop up tent ends and it made a world of difference. I could see how it would work with the windows in 5er.
When we bought our 5er that one request I had, to get the extra AC. we got the 13.5K unit in the bedroom it is NOT ducted and we used twice last summer. First night I had to get under the covers to keep from being cold. I usually sleep on top of them, not the nights we ran the 2nd AC. IT worked fine in the SC hot&humid summer months. We got eh inside down to around 73/75. that was comfortable compared tot eh temps outside. the year before we had the TT with one 13.5K AC I think the best we saw it was 87 inside during the day the AC worked its behind off all day and might have cut off in the middle of the night. One morning it was hot as I was cooking breakfast, I told the wife we were going to go shopping and we stayed at the mall all day long. it got to 99 that day...
I hope you can get it working like you want it. I use a large fan also inside and outside to keep air moving. Keep the all doors closed, pull the shades if you don't go with foil type material.
Randy

[azlee56]

if I search for insulation on Lowes I will find it? We are already have 100 degrees here in Tucson

[JRTJH]

Here's the link:

http://www.lowes.com/pd_13358-56291-BP48025_4294858104__?productId=3011906&Ns=p_product_qty_sales_dollar|1&pl=1&currentURL=%2Fpl_Radiant%2BBarrier_4294858104__%3F Ns%3Dp_product_qty_sales_dollar%7C1&facetInfo=

it's $40.84 at our local Lowes.....

[hankaye]

Howdy All;

Here's the link:

http://www.lowes.com/pd_13358-56291-BP48025_4294858104__?productId=3011906&Ns=p_product_qty_sales_dollar|1&pl=1&currentURL=%2Fpl_Radiant%2BBarrier_4294858104__%3F Ns%3Dp_product_qty_sales_dollar%7C1&facetInfo=

it's $40.84 at our local Lowes.....

I thought I'd read something about using something like the reflectix (stuff mentioned in the quoted link), so I emailed the company...Here's the reply;

We do not recommend it on windows because there can be a heat build up that could cause the glass to crack.

Angelic Millspaugh
Reflectix, Inc.
Customer Service Rep.
Ph: 800-879-3645 ext. 148
Fx: 765-533-2327
"We are all of us stars, and we deserve to twinkle." -- Marilyn Monroe

Thought it warrented a small invistagion.

I think the foil that is refered to is like a window tinting 'film' that is stuck to the glass as a more 'permenant' solutionsuch as;

http://solutions.3m.com/wps/portal/3M/en_US/Window_Film/Solutions/

Disclaimer... I don't work for or have any financial tyes to 3M....

hankaye

[azlee56]

so you think the foil would be ok, but don't go putting on the film? The windows are already tinted, but I was thinking of doing this too.

Did you all put it on the inside or fasten it to the outside (I know someone that did the outside). If inside then it is under the day/night shades correct?:confused:

[smiller]

I just purchased the Montana 3750 and here in my area (TX) the temp has been in the 100 + range for some time, it has dual A/C's but i still can only get the inside temp down to mid 80's during the hotter periods of each day, any suggestion or is something wrong?
The max. input/output temp differential for A/C units is around 15 degrees but that doesn't mean that the max temp differential between inside and out can never be more than 15 degrees. That said, the heat load on an RV on the sun is very high and it is not at all unusual for dual A/C's being unable to keep up in extreme conditions (which virtually defines Texas in the summer :banghead:) About all you can do is take some steps as described in the thread, and start up early in the day so you don't get too far behind the curve.

[fla-gypsy]

I plugged those blasted roof vents with the thick foam with the reflectix to prevent heat gain through them. The difference is noticeable. I never camp without some shade available in Florida and my one 13.5k unit does fine with my 32' TT that is poorly insulated.

[Smitty43]

Yes, I did put it between the day and night shades and the window.

[azlee56]

(tx)
thanks a bunch. That sure would help the big window in the frontroom.

[allentx1]

We had the custom made solar screens that snap on the outside put on. Made a huge difference just standing by the large windows. Normally you could feel the heat radiating in from the glass not it doesn't feel like any temperature difference. Works for homes, works for my RV.

[smiller]

We had the custom made solar screens that snap on the outside put on.
Can you let us know where you got those? I hate fussing with the inside stuff.

[Bob Landry]

The 20 degree temperature difference often referenced is the difference between the return air inside the trailer and the discharge air from the registers, also refered to by people in the A/C business as the "split across the coil". it has nothing to do with ambient(outside) temperature. The outside temp does have some effect in the sense that you are absorbing heat through the skin of the trailer, but it is not used for any type of quantitative measurement or equipment performance calculations. If the trailer is 100 degrees when you turn your AC on, you are going to get 80 degree air at startup. That's not encouraging, but it is what it is. As the trailer cools, you will also see a reduction in discharge air temp, but at any rate, the best you are going to see is a 18-20 degree split if all is working as it should.
You will get maximum efficiency from your units by keeping the filters and coils cleaned, and taping leaks where the ducting is leaking cold air into the roof where it does you no good at all.

[Petlover]

I have a 3750fl with slide toppers and it still gets very hot in the front room. I am considering tinting the windows in the entire camper. The choices are the dark gray for autos or the bronze used in homes (which reflects 75% of the sunlight and heat.)

Has anyone tinted their windows to reduce the heat?

Petlover

[Me.Bikes.Dogs]

I got tint a week ago but haven't installed it yet. I'll let you know how it goes.

[Petlover]

Thanks, I would appreciate it.

Petlover

[Jet Fixer]

Having a mostly black 3750fl Big Sky edition in the 100+ temps of California with both AC's running I too managed low 80's. The owners manual says at best the units will exchange 20 degrees. Finding shade helps the most, but in my opinion slide toppers help some because the sun is not hitting directly on the top. I have em. I'm not ambitious enough to put foil in already tinted privacy windows with shades although I know that too works real well.

[Brebre]

We recently bought a 2013 Dodge 3500. When we went to get our windows tinted at the same place that we have, he asked us if we knew about ceramic tint. He had a homemade box with a sunlamps to show us the difference. I mean the way it cut the heat was unreal. After having it our truck for about a month in August (Louisiana) I decided to see about outin it on my Fuzion 395 toy hauler on all windows except the garage. I don't have to keep my night shades down anymore. It's keeping our unit about 10 degrees cooler too.

[Bob Landry]

The comments about the difference between outside and inside temps are irrelevant. There is no quantitative measurement that will tell you what the inside temperature should be based on outside temperature.The 20 degree difference that people like to reference is the temperature difference between the discharge and return air, also referred to as Delta T. An 18-20 degree split indicates the unit is properly charged and properly sized fpr the space you want to cool. A technician can easily determine proper charge by measuring the current draw of the compressor, but that's a topic for another thread. For the purpose of this one, there are some things you can do to improve cooling. First drop the lower cover and make sure the plenum feeding the ducts is properly taped. That is the biggest shortfall with Keystone air conditioner installations. Put your hand up in the return air chamber. You should not feel cold air being sucked in from the evaporator blower. If you do, retape it. Pull the ceiling registers off and make sure the ducts are sealed where the holes were cut for the registers. If they are not properly taped, you are losing cold air into the ceiling where it is doing you no good.

Finally, the more heat you can reject, the less you have to remove. There are many widow treatments such as tint film, foil faced insulation. heat blinds and probably many that I have not heard of. all of these try to stop the heat radiation after it has already entered the camper. IMHO, Thats a little like the cart before the horse. The window tints are only going to reject 65% of the heat.
Solar/heat reflecting screens is a much better way to go. There are two companies, Phifer and E-Z Snap that makes solar screen that I would consider. They claim 95% heat rejection which may seem a little aggressive, but it's still better than 65% and after comparing samples that both companies sent me, I could not tell any difference between Phiffer and EZ Snap, which was twice as expensive. EZ Snap does have a superior mounting system and that's the one I opted for. There are websites that will sell Phifer by the ft and in several widths. . I measured my windows, cut scaled down patterns and arranged them to allow me to order the width I needed to minimize waste.The EZ Snap studs either attach by drilling into the wall of the RV(No Thanks) or they attach with a super-duper 3M adhesive. I haven't installed my screens yet, but that's a project to keep me busy while I'm at Lake Catherine State Park next week.

Hopefully some of this information will help you cool down the trailer and save you some $$$ in the process, and with Fall and cooler weather upon us, you'll have time to do the research and make a sensible purchase.