Window AC venting to cab

[BlackNBlue]

I've been thinking about what kind of cooling system to install in my step-van build. Rooftop AC is expensive, I already own a household window AC but don't want it protruding from the sides, don't have enough space in the back to fit it, got to scheming up a complex contraption involving ducts and auxiliary fans... and had a lightbulb moment:

Since there will be a fully-insulated bulkhead between the back and the cab, why not install it in that wall, vented to the uninsulated cab? It'll make the cab hotter, but with its large windows and presence of an engine, it's already going to be a hellhole, so what's another few degrees?

Anyone see any drawbacks? Any other opinions?

 

[Every Road Leads Home]

In some of the smaller travel trailers that don't have rooftop units they install it in a sidewall and build it into a cabinet, leaving only about an inch protruding to the outside, just enough for the heat and condensation to exit the vehicle. They have a cover on the outside wall so it looks like a clean finished install

 

[highdesertranger]

what are you going to do with the condensation. plus the cab can get way over 100 degrees which will drastically cut the efficiency of the AC. highdesertranger

 

[BlackNBlue]

For condensation - drain hose. For temperature - good point, and I'm looking into just how much efficiency is affected. However, I won't be running it unattended, so keeping the cab doors or their roll-up windows open should make cab temps about equal with outdoor air. My forseen climates are such that needing protection from rain at the same time as air cooling is vanishingly unlikely.

What I'm also looking into - and welcoming any opinions about - is putting the AC entirely indoors (in the back) to work as a non-cooling dehumidifier during winter months.

Thanks for the thread link, Guy. It's one of those subjects that's hard to search for because there are so many possible words to describe the idea.

 

[ahh_me2]

I actually did that for a while, running A/C in the van with the heat side into the cab.
While it actually worked, meaning it cooled the van, the temperature in the cab was extremely hot.

I tried running with the windows open and it still wasn't enough, I had to have to have the 2 front doors wide open
at which point the stealth factor is completely gone.

I don't recommend it, and wouldn't do it again.

 

[BlackNBlue]

I don't recommend it, and wouldn't do it again.

Oh? I read your post in that thread and you seemed happy with the results at the time. Were there problems besides the heat? Also, what kind of insulation do you have in the back, meaning how much were you actually running the AC?

Since it did work ok (right?) with the doors wide open, my thinking is that if I'm running a generator or shore power, there's no stealth factor anyway. Mine's a stepvan, so the cab is much bigger, the doors are much bigger, and they slide open; a semi-attended stepvan parked with its doors open seems less eye-catching than an Econoline.

Hey, another little lightbulb: an in-window box fan to keep the cab better-ventilated? We're getting slightly Rube Goldberg at this point, but I still see advantages over mounting in an external wall.

 

[highdesertranger]

I am guessing you are stuck in a location that you must have AC? if it was me I would move to cooler climes. highdesertranger

 

[ahh_me2]

Oh? I read your post in that thread and you seemed happy with the results at the time. Were there problems besides the heat? Also, what kind of insulation do you have in the back, meaning how much were you actually running the AC?

Since it did work ok (right?) with the doors wide open, my thinking is that if I'm running a generator or shore power, there's no stealth factor anyway. Mine's a stepvan, so the cab is much bigger, the doors are much bigger, and they slide open; a semi-attended stepvan parked with its doors open seems less eye-catching than an Econoline.

Hey, another little lightbulb: an in-window box fan to keep the cab better-ventilated? We're getting slightly Rube Goldberg at this point, but I still see advantages over mounting in an external wall.

It did work, and I was happy with it at the time.
The back was well insulated, but that vehicle sat baking in the hot sun all day, and being dark brown, absorbed a huge amount of heat.
I have a job in the city, so stealth was/is important to me.

 

[Mobilesport]

Adventure van man on Youtube just did this , it looked pretty rigged up though and he didn't even have a box fan , adding the box fan would look even more rigged up , hes stationary at the moment so it works for him.

 

[DannyB1954]

You would need to install a roof vent in the cab, and have a way for air to get in easy, (like a floor vent).
Once heat is created it can not be destroyed. It can only be moved. The A/C does this by absorbing the heat in one area and moving it in a concentrated form to another area. The temperature of the condenser can be over 150 degrees.

 

[BlackNBlue]

Floor vent would be almost trivial; there's a removable steel panel right over the transmission. Roof vent... not a biggie either, though I'd prefer a high side vent.

The insulation is 4" thick polyiso, though I'm looking to use XPS instead. The van is white and will stay that way, esthetics be damned. I can't imagine ever using AC in a situation where stealth is at all a factor, and those side doors are enormous, so... the concerns are meaningful but it sounds like the idea is quite feasible for my situation.

Moving to a climate where AC is never needed is not an option.