Are portable ACs as effective as window units?

No. Portable ACs are 20-40% less efficient due to exhaust hose heat radiation and (single-hose) negative pressure issues. Window units are more efficient but not always an option.

Can I vent a portable AC without a window?

You can vent through a ceiling tile, dryer vent, or sliding door with an adapter kit. Some users vent into dropped ceilings. The exhaust must go somewhere outside the conditioned space.

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