Thoughts on single hose portables vs window units for high humidity?

I had a similar nightmare with a Black+Decker 12,000 BTU unit last summer in my garage workshop. The negative pressure issue is very real. becuase it's constantly blowing conditioned air out that single hose to cool the compressor, it has to replace that air from somewhere. In my case, it was sucking damp 90-degree air thru the door seals and even the light fixtures. My hygrometer wouldn't drop below 65% no matter how long I ran it. If you realy can't go back to a window unit because of the frames, you need a dual-hose setup like the Whynter ARC-14S. Since it has an intake and an exhaust hose, it doesn't create that vacuum in your room. I also wrapped my exhaust hose in reflectix insulation because those plastic hoses radiate a ton of heat back into the room. It's not as efficient as my old LG window unit, but it actually manages the humidity without making the power meter spin like a top.

I've been using a Whynter single-hose setup in my 1920s guest house for three years and I don't see the 'vacuum' effect as a dealbreaker. The real culprit is ussually the uninsulated hose. These manufacturers ship these thin plastic tubes that radiate heat like a space heater. I bought some cheap sleeve insulation from the hardware store, and it dropped my intake temps significantly. If the hose is hot to the touch, you're fighting a losing battle regardless of the negative pressure. You also have to be aggressive with sealing the gaps. I don't use the standard plastic window sliders alone; I add foam tape and then clear duct tape over the edges. If your apartment has 70% humidity, you likely have air leaking in from the hallway or floorboards, not just the AC unit's exhaust. My 12,000 BTU unit keeps my workspace at a crisp 48% even when the Florida afternoon storms hit. It takes a bit more DIY effort than a window unit, but it's worth it to keep the original wood frames from rotting out under a heavy, vibrating window shaker.

Honestly, those window kits they give you are absolute garbage. I'm over in Tampa and found that even if the hose is 'sealed,' air's still leaking through the gaps in the window slider itself. I had to go ham with some weatherstripping and duct tape to keep the swamp air out. If you're seeing 70% humidity, your unit's prolly just swimming in its own condensate. Check if the internal tank's full—half the time they don't even trigger the light and just stop dehumidifying properly.

You're essentially fighting a losing battle against the laws of thermodynamics because that single-hose configuration forces the unit to prioritize sensible cooling over latent heat removal, meaning it’s dropping the dry-bulb temperature slightly while simultaneously inviting a constant stream of high-dew-point ambient air to infiltrate your envelope through every structural aperture. I’ve found that even with a dual-hose, the inherent inefficiency of the small-diameter condenser fan often fails to reach the neccessary static pressure to overcome the resistance of those corrugated hoses, so you might check if your specific model allows for a shorter, straighter exhaust run to maximize the cubic feet per minute actually leaving the building.

If you’re stuck with portables, you need to jump to an inverter model like the Midea Duo 14,000 BTU (12,000 SACC). Most people don't realize that standard portable compressors are binary—they're either 100% on or 100% off. When they cycle off, that wet evaporator coil just sits there and blows moisture back into your 1903 space. The Duo uses a hose-in-hose setup and variable speeds to keep the coil consistently cold. I’ve seen it outperform those cheap Hisense or Honeywell single-hose rigs every time in the Gulf heat. If you aren't pulling gallons of condensate a day in FL, the machine isn't doing its job.