Update: Mistbox has come out with the second iteration of its device. 

On a hot summer day, all you might want to do is duck indoors and relax in an air-conditioned space. However, it could be costing you big bucks to keep your home cool and comfortable throughout the season. Now, Mistbox is here to lower your air conditioning bills by up to 30 percent, according to its creators.

We first told you about this product back in 2015, but two years later, the Mistbox team has made some major upgrades to its tech. Instead of looking like a portable radio (with a small, boxy shape and a long, black antenna as featured in its earlier design), the device has gotten a lot sleeker. But the technology inside it is still the same — the Mistbox houses a tiny computer, which is responsible for its functionality and efficiency. The computer has sensors that tell the Mistbox when to spray a cool mist toward air entering the AC unit. This process is known as evaporative cooling and it has been around for a while.

In the 1920s, for instance, residents in the Arizona desert would sleep outside in screened porches, relying on evaporative cooling to make things more comfortable, according to the California Energy Commission. People would hang blankets, soaked in water, on the inside of the screens. Then, they would direct electric fans toward the blankets, pulling the cool, night air through the moist cloth.

Through evaporative cooling, the temperature of the outside air can be reduced by up to 30 degrees. This is how the creators of Mistbox intend to help homeowners reduce their energy bills. If the air is already cool when it enters the unit, the AC doesn’t have to work as hard to lower the temperature.

After you attach Mistbox to your AC unit, you feed its tubing into a direct water source. Once it is in place, you can start tracking your power consumption and savings with the Mistbox app on your phone. The device has built-in Wi-Fi, and it’s completely powered by solar energy.

Already, the newest version of the Mistbox has raised 150 percent of its original $10,000 goal and still has more than eight weeks left in its Kickstarter campaign. You can grab one yourself for a $90 pledge, with an estimated delivery in August.