A hot room saps a person’s energy like nothing else. You can drop the temperature with a modern window air conditioner, but there a lot of options when it comes to zeroing in on a unit for the room you plan to use it in. Here are three things to consider when you’ve had enough of the heat.

This product projects in four different directions. LG

A window air conditioner is rated by how many BTUs (British thermal units) its capable of producing. To understand how many BTUs you need to cool a room, match the square footage of the space to a BTU range. Generally speaking, a 150 square foot room needs 5,000 BTUs, 450 square feet needs 10,000 BTUs, and 1,100 square feet needs 20,000 BTUs.

This small unit has two cool settings and two fan speeds. FRIGIDAIRE

A cool room might feel great on your skin, but some window air conditioning units make more noise than others. If you’re installing A/C in a room where quiet is a must, like a bedroom or a nursery, make sure the unit doesn’t run at a high decibel level. A quiet machine runs between 52 and 55 decibels.

This model is also a dehumidifier. LG

Many window air conditioning units include a remote control, but modern models can link to a smartphone app that lets you control your air conditioner even when you’re not in the house.