# Portable Air Conditioners Portable air conditioners are easy to misuse: the wrong BTU number, a leaking window kit or a single-hose setup can leave a room warm despite a running unit. These guides cover sizing, venting and the fixes for common problems. _Last updated: 2026-09-28_ ## What you will find here - ASHRAE vs DOE BTU: which number to compare - How to install and seal a portable AC exhaust hose - Why a portable AC blows warm air - Single-hose vs dual-hose portable AC ## Frequently asked questions **Q: What is the difference between ASHRAE and DOE BTU?** A: DOE BTU is measured under a newer, more realistic test method, so a given unit is usually rated lower in DOE than in the older ASHRAE figure. Compare ratings of the same type; do not compare an ASHRAE number to a DOE number. **Q: Does a portable AC need to be drained?** A: In cooling mode most units evaporate the condensate and need little or no draining, but in humid conditions or in dehumidify mode the tank can fill and must be emptied or connected to a drain. ## Products in this category - [DREO 543S Portable Air Conditioner](https://www.amazon.com/dp/B0H7BMR888?maas=maas_adg_api_585602613512925350_static_12_201&ref_=aa_maas&tag=maas&aa_campaignid=PBd80bd4ce4ece40f44bcc76fcc0c48425&aa_adgroupid=1709F0YoFvn8WQ063L58iFizKDKVpa2b3GHOYuFXiqmLN1RXz8YT3n9by2hV4_a1UOj3lhrTxeHQ0tffeqQbC&aa_creativeid=4c49c7_agox8Dnfln5YFpaffCTsBTExy8Meqw7K_aH3G3MyZo_c) — Best for: Small bedrooms. Amazon rating 4.2/5 (1334 reviews). ASIN B0H7BMR888. - [DREO 516S Portable Air Conditioner](https://www.amazon.com/dp/B0GQGJ6DML?maas=maas_adg_api_585602613512925350_static_12_201&ref_=aa_maas&tag=maas&aa_campaignid=PBd80bd4ce4ece40f44bcc76fcc0c48425&aa_adgroupid=4fb2VYJ6Pwk9zor9pIsuXQFhc0usX44qjhak8BA_a0_bCEu3kAnU_a6FSgwfcH0Hr_bCukAi2CeaMaSoi7gRCJFg&aa_creativeid=9893bt31K2W7fp7u8SAKOBcsuXVYwVj2pwaK5tGNu8S5MIQ_c) — Best for: Larger rooms. Amazon rating 4.1/5 (746 reviews). ASIN B0GQGJ6DML. _Specifications and ratings are manufacturer/retailer figures, not SmartAirGuide measurements. Some links are affiliate links._ --- Canonical: