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[Chance]

Originally Posted by Moondoggie

Thanks Chance. Actually I don't think I knew about the dual hose units. I guess one is intake and the other is exhaust? Dang, I've got a lot to learn. At any rate, the new unit will only need to cool the 80 sq ft. bedroom (8 x 10) Most of what I'm seeing "says" it will cool 150 to 250 sq. ft. The front, where the main unit is, does ok most of the time.

Thanks again everyone. it's getting to be my bedtime.

That’s correct, a 2-hose unit uses one hose to bring outside ambient air to the condenser, and the other hose to return the even warmer air to outside.

With a single hose unit, it draws air from inside the room that has already been cooled and dehumidified to run over the condenser, then rejects that warmer condenser air to outside through the single hose.

The problem with single-hose units is that all air the unit uses for condenser cooling (that has already been cooled and dehumidified) is sucked out of the RV/house and is replaced with warm humid air that has to leak back into cooled space.

Thus, if you measure performance of the unit itself, it looks like it’s doing a great job, but what’s not readily apparent is that it is adding a significant cooling load to the RV/house by bringing in warm and humid outside air that has to be cooled.

There has been a lot of controversy on how to rate these 1-hose units more accurately. I noticed in your specs that it’s rated at 8,000 BTU/hr by ASHRAE, but 4,600 BTU/hr by DOE. This is interesting to me, so I’ll have to look at testing details of both, and compare to typical RV air conditioning standard.


For what it’s worth, if the effective cooling is only 4,600, the EER is horrendous. Even at 8,000 it’s much lower than most window units that size (not suggesting you can use window A/C, just comparing energy efficiency). A 2-hose portable unit should be closer to window unit in efficiency.