A/C Question

[jwh92020]

I'm planning a frame up build of a 7 x12 "tiny trailer". It will be framed with 2 x 2's which will allow for 1.5" poly iso foam board insulation all around, including the floor. This will give a R10 envelope around the trailer. The roof will be white 24 gauge roof metal and the sides will be clad with cedar. How much AC do you think I'll need to survive the AZ desert in the summer should the situation arise?  I'm thinking 8000 btu should handle it, but 6000 would be easier on my generator. I don't want to use a roof unit due to weight, cost & size of generator required to run one. Thanks for any info.

 

[Beetle]

I have a removable 5000 btu through-the-sidewall AC for my 5x8 WeeRoll trailer. The larger WeeRolls use that size also. Works fine.

 

[jwh92020]

Thanks for the response. Will it keep your trailer cool on a 110+ degree day? I'll be traveling a lot between Vegas, Phoenix & Oklahoma City for a while and all 3 places are no fun in the summer.

 

[Gr8ful]

This is what I'm using for my ambulance has somewhat of a soft start & uses 450 watts running & Bob has a video running on solar
Frigidaire FFRA0511R1 5, 000 BTU 115V Window-Mounted Mini-Compact Air Conditioner with Mechanical Controls
#1 Best Seller

 

[LoupGarou]

Consider adding some shade cloth to your build.



The Shade Cloth Store; http://www.shadeclothstore.com/?gclid=EAIaIQobChMIqbHUpYfr4AIVgB-tBh0KtgVPEAAYAyAAEgIJBfD_BwE

 

[RogerD]

I highly recommend the Frigidaire FFRE0533S1. The most it pulls is 410 watts, which it rarely pulls that much. It also has an eco mode that uses less power.

https://www.frigidaire.com/Home-Comfort/...FRE0533S1/

I currently have it installed in a room I made 8x12 inside a workshop. It was nice and cool when it was well into the 90's here in Florida.

 

[jwh92020]

This is what I'm using for my ambulance has somewhat of a soft start & uses 450 watts running & Bob has a video running on solar
Frigidaire FFRA0511R1 5, 000 BTU 115V Window-Mounted Mini-Compact Air Conditioner with Mechanical Controls
#1 Best Seller

Do you think 5000 btu is enough for 110 degree temps in the summer? Here in OK, it would work - we hit 100 during the day but cool down into the 80's at night. The desert is 100+ 24/7 for most of the summer. If it would keep the trailer cool enough, I'd definitely use that one.

 

[RogerD]

This is what I'm using for my ambulance has somewhat of a soft start & uses 450 watts running & Bob has a video running on solar
Frigidaire FFRA0511R1 5, 000 BTU 115V Window-Mounted Mini-Compact Air Conditioner with Mechanical Controls
#1 Best Seller

That's not the AC used in the video.

The one in the video is a Frigidaire FFRE0533S1 and the most it pulls is 410 watts.

 

[jwh92020]

Consider adding some shade cloth to your build.



The Shade Cloth Store; http://www.shadeclothstore.com/?gclid=EAIaIQobChMIqbHUpYfr4AIVgB-tBh0KtgVPEAAYAyAAEgIJBfD_BwE

I definitely plan to use shading. I can't find a picture of it, but I mounted a patio shade on each side of my CTC and used adjustable painter's poles in flag holders mounted to the trailer to hold them up. It made a huge difference and is much cheaper than an awning.   https://www.homedepot.com/p/Coolaro...less-Horizontal-Roller-Shade-460075/203304229 Unfortunately, the pictures got lost in the great Photobucket purge

 

[jwh92020]

I highly recommend the Frigidaire FFRE0533S1. The most it pulls is 410 watts, which it rarely pulls that much. It also has an eco mode that uses less power.

https://www.frigidaire.com/Home-Comfort/...FRE0533S1/

I currently have it installed in a room I made 8x12 inside a workshop. It was nice and cool when it was well into the 90's here in Florida.

I'm going to take a look at it. My only concern is if 5k btu is enough to keep cool in Phoenix in August.

 

[RogerD]

Do you think 5000 btu is enough for 110 degree temps in the summer? Here in OK, it would work - we hit 100 during the day but cool down into the 80's at night. The desert is 100+ 24/7 for most of the summer. If it would keep the trailer cool enough, I'd definitely use that one.

JimInDenver has a 25 ft trailer and uses (2) Frigidaire FFRE0533S1 and says it's very comfortable when in the 100's. Considering your trailer is half the size, it should work.

Scroll to about 8:40 in the video.

For some reason, the link isn't working that I put in my first post about the unit. This one is definitely correct and should work.

https://www.frigidaire.com/Home-Comfort/Air-Conditioning/Window-Mounted-AC/FFRE0533S1/

 

[jwh92020]

JimInDenver has a 25 ft trailer and uses (2) Frigidaire FFRE0533S1 and says it's very comfortable when in the 100's. Considering your trailer is half the size, it should work.

Scroll to about 8:40 in the video.

For some reason, the link isn't working that I put in my first post about the unit. This one is definitely correct and should work.

https://www.frigidaire.com/Home-Comfort/Air-Conditioning/Window-Mounted-AC/FFRE0533S1/

I just watched the video. It looks like that unit works well for him. I would think that my trailer will be better insulated than a factory built unit, so that should help with the cooling as well. Thanks for the link to the video, seeing real life use helps a lot.

 

[jonyjoe303]

Add more insulation, 1.5 inches won't be enough. I'm in southern california and I have 3 inches on the roof and 2 inches on the sides. I started with 1/2 inch and slowly added more layers of rtech foam insulation. 3" inches is the sweetspot in my van. The extra foam will take up more space but to me it improves my comfort level. 

At 3 inches very little heat comes through the roof, a small AC will easily overpower any heat that might come in, I have a small 2 amp swampcooler that keeps the back of my van cool even in the hottest parts of summer. In arizona you might even have to go with 4 inches in some areas like roof corners. Foam is cheap, and the comfort it provides is worth it.

My advice get a IR thermometer and point it around inside your trailer, any hotspots add more foam insulation. I just hotglue my foam, it sticks extremely well to other foam.   

IR thermometer for checking for hotspots (cost 15 dollars)

 

[jwh92020]

Add more insulation, 1.5 inches won't be enough. I'm in southern california and I have 3 inches on the roof and 2 inches on the sides. I started with 1/2 inch and slowly added more layers of rtech foam insulation. 3" inches is the sweetspot in my van. The extra foam will take up more space but to me it improves my comfort level. 

At 3 inches very little heat comes through the roof, a small AC will easily overpower any heat that might come in, I have a small 2 amp swampcooler that keeps the back of my van cool even in the hottest parts of summer. In arizona you might even have to go with 4 inches in some areas like roof corners. Foam is cheap, and the comfort it provides is worth it.

My advice get a IR thermometer and point it around inside your trailer, any hotspots add more foam insulation. I just hotglue my foam, it sticks extremely well to other foam.   

IR thermometer for checking for hotspots (cost 15 dollars)

I've been contemplating adding more insulation to the roof. I talked to RMax tech support today and they said that 1.5" should be sufficient in the walls since the trailer will be wood framed with a radiant barrier over the frame and wood siding over that. They recommended 2" in the roof because it will have the same radiant barrier under the roof metal.

 

[RVTravel]

What radiant barrier will you use?

 

[jwh92020]

I'm using ThermoPly. It is a 1/8" sheathing that is moisture resistant and acts as a radiant barrier as well. I've used it on 2 previous builds and on those I used 1" foam board in a 1.5" thick wall. One trailer was skinned with FRP and the other was skinned with cedar. Both would stay in the low 70's on a 100 degree day here in Oklahoma using a 5000 btu window unit. Here we have 100 degree days & 80 degree nights, so it's easier to keep them cool with a small ac.

 

[RogerD]

You should also insulate the floor if the objective is to hold cold air in.

Hot air rises / cold air falls.

Take a look at LizardSkin, says it will reduce the inside temp of a vehicle by 25-30 degrees.

https://www.speedwaymotors.com/Liza...ermal-and-Sound-Insulation-2-Gallon,2157.html

Page has some videos. The IceCube on a grill is cool and makes it seem like it's legit.

I'm going to try it.

 

[jimindenver]

Hmmmm
Phoenix in August is a lot hotter than I am willing to be in even with both my A/C's.

 

[jwh92020]

RodgerD - The Lizard Skin looks pretty cool (pun intended), but at $800 to do my trailer, I'll have to talk to them about it's performance on a wooden surface. I will be insulating the floor as well.

jim - I spent a couple of years in Phoenix and summers are no fun, but between family and income opportunities there (as well as Vegas and OKC), I'll end up there at some point during the heat. I know you've had success with the 5k btu a/c's, but I question whether they can handle the constant heat, even in a well insulated trailer. I was thinking an 8k unit would keep a 7 x 12 x 6'2" space cool. I'm not going to try and run it on solar, it will be shore power or a generator. If a 5k would work, I'd look at enough solar to run it. I used a 10k unit in a black 7 x 14 x 6'6" cargo trailer that had 1" in the walls & 1.5" in the ceiling. The roof had 3 coats of Henry's TropiCool on it. That a/c kept that trailer at 72 on 100 degree days here in Oklahoma.

 

[Gr8ful]

That's not the AC used in the video.

The one in the video is a Frigidaire FFRE0533S1 and the most it pulls is 410 watts.

No it's not, it's max draw is 460 watts but it starts soft & I can get for $129/shipped. It doesn't have a remote which I don't need.

• Low power start-up conserves energy and saves you money

Also use foil faced Iso board as it has 7R value per inch & tape all your joints.