Owners of two-story homes face the same problem every summer: The upstairs is hotter than the first floor. The choice seems to be to sweat it out or lower the thermostat to make up the difference. Unfortunately, doing nothing can lead to a lot of hot, sleepless nights, while adjusting the thermostat can give you a chill when you receive your summer energy bills. There has to be a better way.

Why it's hotter upstairs

The temperature imbalance in your home has to do with science, but you don't have to be a scientist to understand it. As air gets warmer, its molecules spread farther apart and it becomes lighter. The lighter hot air rises to the second floor. The denser cool air sinks and gets trapped downstairs.

Striking the right the balance

While you can't change the laws of physics, there are things you can do to make your upstairs more comfortable and save money.

• Close first floor air registers. This will divert more of that cool air upstairs.
• Turn the fan setting on your thermostat to "on." This keeps air flowing throughout your home, making the temperature more balanced.
• Use fans. Place fans at the bottom of the stairs pointing upward, sending cool air on the first floor upstairs where you need it. If you have ceiling fans in second floor rooms, turn them on. They will circulate air and make you feel cooler. Switch them off when you leave to avoid wasting energy.
• Check attic insulation. Letting conditioned air escape through your attic makes your upstairs hotter and it costs you money. Hire a qualified contractor to make sure you have the right amount of attic insulation and to check for and seal any air leaks.

Long-term fixes

If your air balance problems are extreme, or you're remodeling your home, consider the following upgrades:

• Cool your roof. Traditional roof materials absorb solar heat and bring it into your home. A cool roof reflects sunlight and emits solar radiation, reducing the need for air conditioning and making your home more comfortable.
• Get in the zone. Install a zoned system, which adds a second thermostat to control the upstairs temperature separately. In some cases, a second air conditioner or heat pump for the upstairs can provide the same benefits. 

Considering an air conditioning system upgrade? Use the Cooling System Comparison Calculator to estimate the cost of operating different types of units.