A/C For Small Trailer/ Bus or alternatives

[Jin+Guice]

I'm living in a converted Ford E450 Bus. I need to get an A/C for the upcoming summer. Does anyone have any recommendations or alternative ideas? The bus gets full sun (solar panels... would be cool to run the A/C off of them, but not counting on it/ have access to grid power) and temps are between 90-100.

Right now it needs to vent out of a window that is 7" by 7.75"... so probably tube vent... a stick in the window unit is not going to work right now (it's possible to alter it for this, but that's beyond my skill set.

The bus is super small (old person bus) and I'm fine with inside temps in the high-70s, especially if it's dehumidified a bit.

Swamp cooler is not an option as this relies on dry air and the air here is about as wet as it gets.

I'm also interested in what to do about getting some sort of shade structure vs solar panels. The bus is also painted black now, which is not ideal, but does look pretty cool. I'm interested in repainting it, I'd like it not to be so heat absorptive, but also are about aesthetics.

While I'd love to come up with some out of the box solution, the primary thing I need to do asap is figure out some sort of traditional A/C for the upcoming summer and this is a problem that I'm willing and able to pay to solve.

[Slevin]

I'm also interested in what to do about getting some sort of shade structure vs solar panels. The bus is also painted black now, which is not ideal, but does look pretty cool. I'm interested in repainting it, I'd like it not to be so heat absorptive, but also are about aesthetics.

I don't know if you have to move the bus often, but if not, first step should be to put up a tarp shade of some sort over the bus, removing the extra heat incoming from the sun before you have to pay a lot of electricity to remove it. Pretty much any shade sail type of thing can work, and if you are on your friends property you can maybe just smash some tall aluminum posts into the ground (at an angle away from where the shade sail will connect), then set up the shade structure off that.

Then yeah, it doesn't matter, AC all works the same. Do a cost / benefit of the SEER ratings (efficiency at moving heat) and electricity costs versus how long you are gonna need this thing, then buy a corresponding mobile AC unit. Use some insulation + plywood + duct tape to fit the ducting onto a window, and make sure that the venting pressure is okay (not leaking into your van).

That's basically best you can do without getting really complicated about it.

Also, if you can, obviously eventually you should build a shade structure out of solar panels so you get both the shade and the power for the AC. Used solar panels are weirdly cheap .

[AxelHeyst]

You can buy standalone ACs with tube vents (I believe they include kits to match window openings). Pretty sure these units even have casters so you can scoot it around easily. Get a unit that’s rated for a bit more square feet than your bus is and you should be good on capacity. You won’t probably be able to find a unit *too* small, but I’m not sure.

Second thing I’d do is buy a gallon of Henry’s RV Cool Roof paint and paint the roof. I might have the name slightly mixed up but you’re looking for stuff designed for metal RV roofs. The difference this paint makes is huge. Read the application directions, they’re important to follow correctly.

Then I’d look into roof mounting solar panels which will also shade roof. Options for creativity here, would need to see pics again.

For the sides, one idea is to get shade cloth (eg for greenhouses/hoop houses) and make shade awnings on the south and west exposure for your bus, to keep sun off sides but not have to repaint. Options for creativity here too.

[Jin+Guice]

Thanks y'all!

Slight clarification: The bus came with a ready to rock solar system (previous owners who did the convert had lived in the bus for several years) and the solar panels are already roof mounted.

When I asked about shade structure vs solar panels, I meant how do I address the tradeoff between loss of solar energy and shading the bus, which I was not clear about.

Bus is currently stationary in a friends backyard. I use very little electricity currently because I have access to my friend's house.

[Slevin]

Can you take them off and put them on a stand next to the bus that isn't in the shade? Or is that liable to cause a leaky roof / be overly complicated? Is it a lot of panels? I.e. it could be worth it to just shade the bus and then wire up different panels to your actual electric system, if it isn't a massively expensive ask.

[Jin+Guice]

@Slevin: I have no idea what I'm doing, so, probably not for now. I'd also be open to expanding the solar setup, particularly to run an A/C off of. I'm into the shade structure out of solar panels idea, but not for this year as I lack the skills. I also need to check with my friends before putting anything in their yard, especially permanent (their likely to say yes to anything temporary).


Has anyone fucked with one of these ice-chest coolers? Are they a possible solution or underpowered or a gimmick?

Thanks again for the help y'all!

[jacob]

We actually have an A/C with a tube vent that we bought for our previous apartment, because we weren't allowed to hang anything out the window. In summary, it works, but not very well. You basically have a hot compressor inside and you're trying to cool it by blowing air from the inside over the heatsink to the outside. This creates an underpressure which sucks in warm air from the outside through some leak or gap. This makes it pretty hard to win.

A regular window unit that has the alu heat sink hanging on the outside is much better. Also cheaper. Attach it to window with foam boards. You could even make a hole in the wall. You'll have to remove it for driving.

There are also RV A/Cs (6x+ the price) that you could put on the roof. They still run on 115V. A/C is just a power-hungry job! (A swamp cooler is cheaper/DIY and can run on 12V... but the air needs to be dry!) I highly recommend against putting more holes in the roof than you absolutely need to to avoid a long battle with caulking and sealant that you'll eventually lose.

For shading, you can get one of those tent-carports. They come in all sizes. https://www.amazon.com/Outdoor-Carport- ... B0CXWTSXGH ... or you could frame your own and put a tarp over it. We used a billboard (very strong poly) to cover our RV in the winter. Like e.g. https://www.ebay.com/itm/166468054303 ... they also come in many sizes from big to very big!

Putting alu-foil right up about the window (no air space!!!) also works fantastic! Just use masking tape. We've even used it on some of the windows in the house.

Painting your bus white---prison style---would also help a lot. I really wonder when I see black/grey color schemes on RVs.

Whatever you do, DO NOT PARK UNDER A TREE!! The dripping sap will make a mess of your roof. You don't want to park over vegetation (like grass) for similar reasons. The moisture will rust your undercarriage.

It's hard for me to believe that a PV system and 12V appliances would in any way be cheaper than an extension cord and regular consumer appliances.

[Jin+Guice]

@jacob, thanks for weighing in. I'm a bit concerned about a window unit making the bus easier to break into. Not sure how much I care about this. Windows are also a weird size... I think a small window unit would maybe fit though? I'd have to see. I'd also need to fill in a bit of open space... I'm sure it's doable though.

I've had tube vent AC units that worked relatively well before in a regular apartment, but not sure on the specs.

Thanks for the tip on the tree and the other tips!

PV system came with the bus, so locked in now. I really have no idea about PV or electrical stuff so can't provide any info or make decisions. It runs a fan at night and charges a laptop and for all that's all I care about, lol.

[AxelHeyst]

AC/DC chest style fridge/freezers are good, I have one. I assume they’re more expensive than a normal house small fridge? Def not a gimmick, although there’s a range of quality. I have an iceco and it runs great.

[Jin+Guice]

@AH: There are ice chest AC units. Supposedly the ice helps cut down on power usage?

Here's the first hit on google: https://www.icybreeze.com/

[7Wannabe5]

In Victorian times they kept human bodies from decomposing in the morgue by running cold water over the slabs. You could hook up a hose with a timer so that it sprayed cold water over the van on an intermittent basis and/or refilled your mini-water-bed with cold water. This could even be accomplished to some extent with a large DC powered drinks cooler.

[jacob]

@AH: There are ice chest AC units. Supposedly the ice helps cut down on power usage?

Only if you get the ice for free #thermodynamics

[ffj]

The thought of living in a metal box in the humid Louisiana heat makes me ill, literally. But I'll have a go at your situation if only to save your life, haha.

If you have access to regular AC power, the window unit is the way to go. It's cheap and very effective. Cutting a whole in the side of the van is not hard and if you do it right, burglars will have a hard time removing it and bugs and outside air will stay out of your abode.

As mentioned already, keep the sun from baking your house. Find one of those huge live oaks and plant yourself underneath it while also protecting your roof with another reflective shield such as a tarp that allows air to move and moisture to evaporate. It will also keep water out and maybe create a covered picnic area. You can also put reflective shields in your windows to keep the sun out.

I wouldn't count on solar panels powering an air conditioner. At least not the small quantity that would fit on a van rooftop. I would remove the panels and make a stand for them so they stay in the sun while your house is completely shaded. Much better yield then keeping them on the roof. I assume you won't be driving constantly.

Don't forget consistent breezes if you are lucky enough to have them. Orient your van to maximize air flow. This also includes utilizing powered fans as they make a tremendous difference, especially with an AC unit.

Good luck

[Gilberto de Piento]

I'm guessing this has already been done or is impractical but what about air sealing and insulation to help keep the cold air from getting out?

What about window tint, reflective window coverings, or window shades to keep the sun out?

[mooretrees]

Our tips for keeping our bus cool:
- move to higher elevation firstly
-orient the bus with the least amount of sun exposure if possible
- white paint on roof
- cover all direct sun windows with reflextix
-fans
-window ac unit. We found a small one a few years ago and it fits in our bus windows. I think all windows are standard so you should be able to find one.

[Hristo Botev]

If you have access to regular AC power, the window unit is the way to go. It's cheap and very effective. Cutting a whole in the side of the van is not hard and if you do it right, burglars will have a hard time removing it and bugs and outside air will stay out of your abode.

This is the smallest window ac unit I was able to find for my shoffice project: https://www.homedepot.com/p/GE-5-000-BT ... /315262616. I just cut a hole in the metal siding and framed around the ac unit, and added some insulation, caulk, etc. the unit is screwed in to the support framing so a robber would have a hard time removing it to get inside. The shoffice is only 100 sf but this ac unit provides way more cooling than I need. Seems like the same principles would apply for a metal bus as would a metal shed.

I looked at doing a tube vent portable ac unit but ruled it out for the reasons Jacob mentioned.

[Jin+Guice]

Thanks everyone for all of the help!!!

@mooretrees: I don't have a school bus so window sizes are likely different. It's for sure not school bus windows.

I measured the window I've got, it's roughly 28 inches tall by 24 inches wide. A little bit bigger than that in both dimensions it appears.

I'll probably take a few more days to decide, but based on the huge endorsement of window unit, I'll probably try to go window unit. The unti @Hristo sent looks like it will fit in my window.


If I got this route, how should I seal the rest of the space?

Thanks again everyone, I really appreciate everyone's help. I'm really grateful for this community and how willing everyone is to give advice.

I'll also be implementing some of the passive heat reduction techniques listed here (no decisions made yet). I'll try to keep this thread updated with what I'm doing and how it's working. I'm sure I'll need more help along the way.

Please keep the recs coming in! It'll take me at least a few days to even make an AC decision.

[Hristo Botev]

I'll probably take a few more days to decide, but based on the huge endorsement of window unit, I'll probably try to go window unit. The unti @Hristo sent looks like it will fit in my window.


If I got this route, how should I seal the rest of the space?

There are plenty of people with way more knowledge and competence about this, but in case it's helpful, here's my install progression for my a/c unit in the shoffice:





(I've not finished the finishing details on the frame around the unit in the last photo, so don't judge me too harshly.)

ETA: Note that they make versions of window units that are designed to go through the wall, like I did here, the main difference of which being that they come with a metal sleeve that the a/c unit sits in. That probably would have made more sense for me to do with the shoffice, and it might make sense for a bus buildout like you are planning, but in my quick search at the time I wasn't able to find any that were as small as I was looking for, and it seemed like the cost for the through the wall unit was a couple multiples more than what the equivalent window unit would be, for no reason other than, apparently, the novelty of the through-the-wall set up vs. the ubiquitous window units. So I just went with the smallest and cheapest window unit Home Depot had in stock.

[Jin+Guice]

@Hristo: Thanks for the pics. In my mind, I'm modeling everything off of my urban garden friend. He has a Shipping Container with 2 holes cut in it, one for the door and one for the A/C. He has a small window unit A/C. Shipping container is slightly more sqft than my bus. Works great in the NOLA summer heat in a metal box (painted yellow instead of black... repainted the roof white myself while I lived there).

My concern with the bus is, structural integrity of putting a hole in it, plus how it might compromise driving the bus? As I know nothing, these are just concerns that popped into my head.