It's a common problem: you turn on the air conditioning and your downstairs gets really cool, but the upstairs of your home stays warm. This issue is most common in older homes where HVAC systems were not initially built with air conditioning in mind, but it can happen in newer homes with minimal ductwork, too. Luckily, there are a few steps you can take to encourage your upstairs to cool off more effectively.
Close any doors between the floors.
One of the reasons upstairs floors are hard to cool is because heat travel upwards. Your AC unit may be depositing plenty of cold air up there, but it just can't keep up with all of the warmth traveling up from downstairs. By closing the doors between your floors, you keep heat from continuing to rise into the upstairs of the home. Essentially, you're "trapping" the cool air upstairs.
If you do not have a door between your floors, it may be worth your while to install an inexpensive, temporary one. You can find accordion-style doors that can be mounted to one side of a wall and pulled out to extend across a stairway or wall. They're easy to install with a drill and some screws.
Close a few downstairs vents.
Since your downstairs is cooling off well, you can probably afford to close a few vents down there. Do so in the downstairs rooms you use the least. This will essentially leave more cooled air in the system, so more of it is deposited into the upstairs of your home,
Check on your insulation.
Insulation is typically seen as a way to keep your home warm in the winter. But it also functions to keep your home cool in the summer. If your attic is lacking insulation, then heat from the roof is probably making its way into the upstairs, combating the efforts of your air conditioner to keep it cool.
In most areas, you need two layers of fiberglass insulation to insulate effectively. If you only have one, unroll a second one in the direction perpendicular to that of the first layer. If your current insulation is discolored, damp, or squished, it's not doing its job as well as it could. Pull it out and replace it. Your upstairs will stay much cooler as a result.
If your upstairs is still too warm after following these steps, contact a local HVAC company, like Boyers R S Heating & Air Conditioning Inc. You may need a larger air conditioner or some duct modifications to cool your home more effectively.