Portable air conditioners are not only versatile, meaning you can move them from room to room as needed, they can also double as dehumidifiers. They are also remarkably easy to install, unlike boxy window units that require quite a bit of effort. But if you’ve ever looked into buying one, you know that it can be confusing to distinguish what kind of unit will work for you. Read on to find out which unit will be just right for your space.

This model not only cools, it also controls humidity and provides ventilation. BLACK+DECKER

First, a quick primer on BTUs (British Thermal Units), the main measure of energy output in air conditioners. The higher the BTU, the more square footage you can cool. For example, an unit with 8,000 BTU is perfect for cooling about 300-400 square feet. More square footage means you’ll need a higher level of BTU to keep it comfortable. If your unit will be installed on an upper floor where heat rises and gets trapped, opt for a slightly higher number of BTU than you might otherwise in order to mitigate that stuffiness.

Compact unit for cooling a bedroom, office or other modestly sized living area. BLACK+DECKER

One helpful feature of portable a/c units is their dehumidifying power. You don’t have to only use it to cool down warm spaces—one can also pull excess moisture from the air. This function is especially helpful in humid climates, as it makes the conditioned air feel cooler. It also helps suppress mold spores that thrive in warm, wet environments.

Powerful enough to cool up to about 700 square feet. Honeywell

If you’ve ever installed a window a/c unit, you know how awkward it is to balance the heavy box while trying not to drop it. Securing it safely in the window can also prove tricky. Portable a/c units have a single venting hose that installs quickly into any 4- or 5-inch wide window opening, and draws hot air outside where it belongs. And because these a/c units are portable, you can wheel them anywhere you need them most.