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Discussion Starter #1
Please forgive me... I know this subject has been beaten to death.

I'm in the process of picking an A/C unit for my new build. Of course initially, I was hoping the U.S. RV industry had developed the technology for more efficient A/C options... even hoped I would find a DC version that I could run off an inverter... don't worry... I've given up on that idea!! It seems Europe has figured these things out... but what's available here seems outrageously expensive or just not possible.

I'm assuming a rooftop would provide the most performance... and is probably what I will choose.
However, I really hate the idea of adding height to the roof.

In my last van I used a single hose portable. It takes up a lot of space, and although it was better than nothing... on hot days it did very little.

I know others have used window air conditioners... but the results seem to be about the same I had with the portable.

So... before I give into the rooftop and adding height that I don't want to... I was wondering if anyone has had any experience with a RV under the bench A/C unit? I'm not referring to household window type A/C... but to the units specifically made for RVs. Just curious if they perform as well as a rooftop? If you did use one, would you use it again, etc.?

Here is a link to the type of unit I'm asking about:
https://www.dometic.com/en-us/us/products/climate/air-conditioners/air-conditioners-for-rvs/cool-cat-_-20788

Thanks,
Tom
 

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Have you seen this thread? http://www.promasterforum.com/forum/showthread.php?p=464738#post464738

I'm with you, I don't want to use my precious rooftop real estate for an A/C unit. A really well insulated unit should be easily cooled by 5,000 BTU's. ****, it's hardly 75 sq. feet! Also, I intend to make some zones with curtains and walls to only have to cool the "bedroom" or "living room/kitchen". The cab could also be closed off to not cool that much.

Too bad they don't make a smaller unit like the dometic. What do they use in Europe? Maybe we could acquire something...

In the end, I'll probably go with a little 5,000 BTU window unit, like a Frigidaire, but I won't be in love with the fact that I will need to buy extra batteries and solar just for that.
 

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Discussion Starter #3
Thanks jrosser1,

Yes, I read that thread with great interest... but I'm not convinced it's any better than using a portable. In the end for me, I'll probably go with a rooftop because it seems to get the best score for cooling performance. I would definitely use an under the bench unit if I knew they performed well. My fear is the floor will be cool, but the rest of the van will not be :).

Europe seems to have smaller units, 12 volt models, etc. But they use a 230 volt power system. For an example, check out the Dometic products they sell in Sweden:

https://www.dometic.com/en/se/products/climate/air-conditioners/air-conditioners-for-rvs/dometic-freshlight-2200-_-20662

Look through the rest of their offerings... even their generators seem smaller and easier to work with.

I enquired to see if there is a US version of the Freshlight rooftop and was told there wasn't, nor are they planning to offer them. When I asked if I could run it on our power supply with an adapter, she said we would need a very expensive converter... but didn't know what kind or where to buy them.

More than likely, I'll end up with a rooftop... unless I hear from someone who has had a great experience with an under the bench unit.

Good luck with your build... it will be interesting hearing what you decide.

Thanks, Tom
 

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Anyone install a two pipe portable small enough to fit between the front seats using the front windows for intake and exhaust? I feel I could roll it back and lash it for trips and store it in the house (the Ms. wants it) when at home. For 6 months it could stay in the garage out of the way. 110V is Ok as I’d use it in the East and everyone seems to have electrical hook ups. Right proeddie?
 

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Cool Cat air conditioners I've seen require a very large opening on side of RV for venting condenser. Mostly I've seen them on small trailers where they were trying to keep height low (like on [email protected] trailers show in attached picture) or on pop-ups where a roof A/C isn't practical.

They are now higher-capacity at 13,500 BTU/hr than I recall previously, and seem physically large too.
 

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Discussion Starter #6
Thanks Chance,

I knew they required a large vent opening on the sidewall... I'ld be OK with this if they function as well as a rooftop. The trade off would be not having to increase the height of the van. I figure we have to make holes either way :).

Can't find any reviews on them anywhere.
 

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I have a Danhard unit, which has the condenser and compressor mounted under the rig, and the evaporator inside. The compressor takes [email protected], with the fans being run on 12VDC. The specific unit I have is a custom build Danhard does for Sportsmobile, but the parts are available from Danhard themselves. You often see this sort of unit installed on tractor-trailer units, with the fans on the back of the cab. I can run mine off the inverter and batteries for a short time, and run it off the inverter + alternator pretty much indefinitely.
 

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Discussion Starter #8
Thanks Wowbagger,

Have you've been happy with the Danhard's performance?

Can you post a picture of your set up?

I went on their site... but I can't figure out which parts I should be looking at :).

Sounds like nice alternative... Thanks,

Tom
 

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Hi,
I would not group window AC units with portable AC units on efficiency -- especially single hose portables. The EER of the portables is around 8 while you can easily find 5 or 6K BTU window AC with and EER of 12.
The EER 12 window AC would use 500 watts to produce 6000 BTU of cooling.
The EER 8 portable AC would use 750 watts to produce 6000 BTU of cooling.

The window ACs are also a fair bit more efficient than the RV roof AC units, not to mention being available in smaller sizes that are a better match for a van conversion.

I think a 5 or 6K BTU window AC unit could cool a well insulated van with reflective window treatments.
I think this setup could be efficient enough to run the AC off a largish house battery setup for a useful amount of time.

The problem with window ACs for the van is installing them in such a way the condenser gets adequate cooling -- if you don't do this, the EER will fall off.

Take a look at the 12 volt AC units you are thinking about and see what their EER is -- if they don't publish one, I'd be suspicious. EER is (BTU of cooling) / (power consumed in watts), so if the give max cooling capacity in BTU and the power in watts that goes with it, you can estimate the EER.

A couple links:

and

Gary
 

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IMO it's a fancy overpriced swamp cooler, good for dry heat, poor for hot and muggy.
 

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Roof vents, fans and windows will work most of the time depending temperature, RH and dew point.

We had a few nights here with high temp and high dewpoint, god awful, went back inside where the A/C was.
 

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I have a window AC, I did a thread about it and tested it on a 99 degree day here in Texas with the van in partial sun. 5000 BTU/ hr is enough for a well insulated van in the shade.

That said, I built my current van and bought my first (a factory built 1989 class B on a dodge b350 chassis). I had a generator in the old van and roof air. I have a 600AH lithium battery bank with a window unit in the current van. I rarely used either in the 4 years I have been living out of these two vans (part time). One was my home away from home in Birmingham, AL and the other is used in Connecticut.

In my experience the number one factor that determines the need for air conditioning is the overnight low temperature. If it is 100 in the day, ok, you aren't planning to sit inside the van in the middle of the day right? but if the overnight low doesn't get down close to 70 you won't be comfortable to sleep and that is kind of the point of having the van as a place to sleep.

With the right ventilation even 80 is not terrible, but you need really good ventilation. I have two roof vents (no windows in the conversion area, only one in the rear doors and the normal cab windows. I have a gimbal fan mounted near the bed.
 

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Thoughts on the Fresair? Relatively new product I guess. VanLife - Fresair
Hi,
The evaporative coolers are good for some dry climates -- see the map on this page:

In climates where they are effective, they are much more efficient that regular AC units and they can be run off a much smaller house battery.

So, I'd say, it depends on where you plan to travel.

The $1500 price for this one seems really high for such a simple device.
There are DIY (and commercial) ones on this page:

Gary
 

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Gary is correct about swamp coolers (as he seems to be about many things). In the climates where they work they are a very effective alternative that used much less power (but more water, which can be scarce in those climates).

The main problem is the climates where I have experienced the most need for air conditioning are those with a high level of humidity and dew point which keeps the temperatures from dropping as much overnight.

If you can carry the water and are in a dry climate, a swamp cooler can be the answer.
 

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I ended up getting a maxxair-- partially because I finally found one ready to ship, and partially because the humidity past few days have me thinking I'd be disappointed by the fresair, and partially because I'm just now learning about Tennessee sales tax on a NH purchased vehicle and... wooooof. My conversion budget just contracted by about $2k.
 
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