Every portable AC in this family is designed to exhaust warm air outside — venting anywhere else defeats the purpose.
Why outdoor venting is not optional
The unit removes heat from indoor air and exhausts it, along with the warm air itself, outside. Venting into another indoor room, a hallway, or an unsealed gap doesn’t remove that heat from your home — it just relocates it, and often makes the exhaust destination uncomfortably warm.
Some manufacturers offer a wall-adapter accessory
Dreo states a separately available wall-adapter accessory for the AC318S, for installations that don’t use a window at all — worth checking whether your specific unit’s manufacturer offers an equivalent option before assuming a window is the only route.
A dedicated wall sleeve is the more permanent alternative
A small, purpose-built opening through an exterior wall, fitted with a proper sleeve, gives a portable AC a permanent, well-sealed vent path without relying on a window kit at all — a bigger step than a window installation, but a genuine option for a room with no suitable window.
Don’t improvise a seal through a door gap
Venting a hose through a door left ajar, with no proper seal, both looks and performs like a poorly sealed window kit — warm air gets pulled back in continuously, and the setup is also a security and draft concern.
What we would not do
Suggest that venting indoors, even into an unused room, is an acceptable substitute for proper outdoor venting. It doesn’t cool your home overall, and it can create a new heat and humidity problem in whichever space receives the exhaust.
Check your own manual before you follow anything here. Humidity ranges, wattages, voltage and current ratings differ from model to model, and the manufacturer's figures take precedence over anything written on this site. We report what makers and monitors publish — a target humidity percentage, a heater's tip-over and overheat protection, a plug or thermostat's maximum load rating — and we never turn a reading into a health verdict or a diagnosis. Questions about air quality and health are matters for a qualified professional and your national health authority, and this site points you to them rather than restating them. Where wiring, voltage or load ratings are involved, matching them exactly to your appliance is a safety matter, not a technicality.
The questions that keep coming up
Can I just vent the hose into another room instead of outside?
No — this exhausts the heat the unit is removing from your room directly into another indoor space, rather than outside, which does not actually cool your home overall and can make the second room uncomfortably warm.
Last reviewed 24 August 2026