lightweight Roof Air Conditioners?

[LJ-TJ]

As we all know, older winnies Roofs sag because of the weight of the air conditioner and due to the weakness of roof structure support.  So, the question that begs to be asked is, if one was looking to replace their roof air, what is the lightest and most efficient air conditioner on the market that would cool a rig which is 1,176 Cubic Feet?  i??

[Oz]

Most, standard size (13,500 btu) roof air conditioners weigh in right around 100 lbs, give or take maybe 2 lbs.  With a 21' RV, you may find a 10,000 btu air conditioner adequate for the job.  These run about 95 lbs.  Even a 8,500 btu unit weighs in at about 88 lbs.  A high efficiency, 7,000 btu unit is about 75 lbs, which is quite a bit lighter than the standard, 13,500 btu units these vintage RVs were originally equipped with and are good for cooling smaller rigs.  However...

You also need to remember that these lower btu units didn't come into play until ducted air systems were put into use.  The roof depth is much greater and the newer RVs are more insulated.  I seriously doubt anything less than 10,000 btu would do the job for you with a standard, non-ducted system. 

So, you're going to be sitting at 95 - 100 lbs (Unless you want to have a really fun project:  making a ducted system.)

The remedy:  you have to cure the real problem.  It's not the weight of the air conditioner, it's the support for it.  You could put a 75 lb unit up there and you know what's still going to happen over time...

We've seen a few members here post different ways to fix this issue.  Everything from a complete, arched roof make-over to an on-top-of-the-roof, steel brace.  Stop the sag = fix the support.

Edit:  JD just "bumped" up this recent topic for you to look at, TJ

http://www.classicwinnebagos.com/forum/index.php?topic=3114.0

[ibdilbert01]

The PO of my rig ran metal tubing across the roof and the air conditioner saddled the tubing.   Wish I had taken pictures before I tore off the roof.   

[Oz]

That's sounds exactly like the one a member has posted photos of back on the MSN site.  The tubing extended out to the side drip rails and had the 14" x 14" square in the center.  He just sealed the center shroud extension in the original roof mount opening.

[ibdilbert01]

I wonder if I now have that members rig.....     Hm?

[Oz]

As we all know, older winnies Roofs sag because of the weight of the air conditioner and due to the weakness of roof structure support.  So, the question that begs to be asked is, if one was looking to replace their roof air, what is the lightest and most efficient air conditioner on the market that would cool a rig which is 1,176 Cubic Feet?  i??

I don't think any of us have actually bought, mounted, used and evaluated every model available by each manufacturer so, that's most likley why you didn't get any responses.

What to do?  Look at the manufacturer's websites and the different models and note the weights and dimensions and the usage and compare them.

[DELTA912]

My evaporative cooler weighs 30 or so pounds when wet. but I like my vintage Bycool that fits in a 14X14 vent hole. There was a vent there but the PO took it out and put that in its place.

[Oz]

That's what they call a "swamp cooler", correct?  And it's a completely different animal than an air conditioner.  A good topic on evaporative coolers can be found here if you want to look at that as an option:
http://www.classicwinnebagos.com/forum/index.php/topic,7705.msg37591.html#msg37591

However, an actual roof air conditioner of 13,500 btu output is going weigh between 99 and 105lbs, from the last time I checked for a replacement, which was around a half-dozen years ago.  So, unless they've made some significant changes in design, that's what they will weigh-in at.  99lbs was the lightest I found and that was a Carrier V, which is no longer manufactured.