Locate all of the vents on the second floor and check to see if they are blocked in any way.
How to keep 2nd floor cool.
Keeping your blinds closed in areas that are unbearably hot will reduce the temperature of your upstairs.
Fully open each vent to allow for maximum air flow.
Remove any furniture blocking the air flow.
Divide the house into two zones one for each floor.
If you allow sunlight to shine in through a window you are adding heat to your home.
To prevent the heat from rising separate the two floors with a door or curtains so your efforts to cool the second story are not lost when heat from below rises to replace any cool air.
Air sealing prevents conditioned air from leaving the home.
Add a small return vent duct to each room on the second floor.
Use curtains and drapes to block sunlight.
Set the fan to be on all the time.
Open doors on the second floor so air is more evenly distributed when using a central ac system close doors that lead to rooms where cooling isn t a priority when using a supplemental ac unit upgrade your thermostat to a programmable or smart wifi version.
Use a floor fan or ceiling fan to improve or direct cold air flow upstairs.
Keeping cool in a 2 story house from a lot of experience i can say that a simple easy to implement yet significant contribution to improving a 2nd floor that gets too hot in summer is to install insulating shades lower them in the morning then raise and vent at night.
Consider installing power or ridge vents to help cool the attic and provide better ventilation which also helps prevent ice dams in winter.
This will block the excess heat from the sunlight.
These appliances draw excess moisture out of a room and collect it into a bucket for disposal or routed into a drain.
Slightly restricting airflow to your first floor will increase the volume of cool air to your second floor balancing out comfort.
If humidity is the chief agent behind your second floor not being cool enough you should look into purchasing a dehumidifier.
To handle this problem there are four common ways to improve cooling on your second floor.
Air seal the windows in the attic and second floor.
Reducing the airflow to the first floor with also ensure longer cycle times as your thermostat is most likely on the first floor as well.
Longer cycle times mean more cool air is getting to the second floor.