It seems like a central air conditioner blows cold air into your house and that's all there is to making you comfortable. However, there's a little more to how an air conditioning system works. An AC has three important roles in treating your indoor air. One is to remove heat from the space, another is to reduce humidity, and the third is to filter the air. Here's a closer look at each of these roles and how you can ensure your AC does the best job possible at keeping you cool.