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.
But ! With this one you just need to attach a second hose securely. Done !

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

If you like what you see, and want to help out making this sort of development and production possible in the future, please consider a small donation at:
https://www.paypal.me/dherrendoerfer
This helps a lot in keeping the channel and its content free and un-influenced.