Can you convert a single-hose portable AC unit to a double-hose setup and gain tons of efficiency ?
Read on.

The answer in short is yes. But it's way more complicated than just fixing a second hose to the back air inlet.
In a dual hose AC unit there's a separation between the high and low pressure chambers to make sure that the two air sources don't mix. This is missing in a cheap single-hose unit.
For my unit, I had to seal up the area surrounding the compressor and condenser so the air would not get pulled in from the cold side of the device.
Just attaching a hose even lowered the performance.

The final result is surprisingly effective, and beat my expectations.

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