This guide is based on independent research into published specifications and standards. South Report has not physically tested the products discussed, and it does not name a single winner where the right choice depends on your setup.
A portable air conditioner can be the most practical option for renters who cannot install a window unit. It needs a way to vent hot air outside, so check your windows and your room size before comparing models.
Choose the right size
Air conditioner capacity is measured in BTUs. ENERGY STAR publishes this general guide for room air conditioners:
| Room size | Capacity |
|---|---|
| 100 to 150 sq ft | 5,000 BTU |
| 150 to 250 sq ft | 6,000 BTU |
| 250 to 300 sq ft | 7,000 BTU |
| 300 to 350 sq ft | 8,000 BTU |
| 350 to 400 sq ft | 9,000 BTU |
| 400 to 450 sq ft | 10,000 BTU |
Increase capacity for very sunny rooms, kitchens or rooms with high ceilings. In the US, compare the DOE SACC rating on portable units if it is listed, as it reflects real-world performance better than a headline BTU figure.
Single hose or dual hose?
- Single hose: simpler and often cheaper, but it pulls warm air into the room from outside as it exhausts.
- Dual hose: takes in outside air through a separate hose, and usually works more efficiently in hot weather.
Check your window
Most units include a kit for sliding or hung windows. Casement or unusual windows may need an adapter, and you should check your lease or building rules. Keep the hose as short and straight as you can, because a long or bent hose reduces performance.
Noise and drainage
Portable units contain the compressor inside your room, so they are louder than most window units. Check decibel levels if the unit will be in your bedroom. Many models evaporate most of their condensation, but some need a tank emptied or a drain hose fitted in humid weather.
Electrical safety
Plug the unit directly into a suitable wall outlet. Follow the manual on extension cords, since most manufacturers advise against them, and check that the circuit is not overloaded by other appliances.
Improving comfort at home? See our Bedroom & Comfort guides and air purifier guide for small apartments.
