Design Green Design This Little Solar Gadget Uses Evaporative Cooling to Cut AC Costs Up to 30% By Derek Markham Writer Derek Markham is a green living expert who started writing for Treehugger in 2012. our editorial process Twitter Twitter Derek Markham Updated October 11, 2018 ©. Mistbox Share Twitter Pinterest Email Design Tiny Homes Architecture Interior Design Green Design Urban Design By adapting a proven technology used in commercial AC units to home central air conditioners, Mistbox increases the efficiency of the units, saving up to 30% on AC costs. As we get closer to summer, keeping the inside of our homes cool begins to be one of our priorities, but running an AC unit to do so can come at a high cost, not just in money, but also in energy. AC costs can quickly add up during hot weather, but there's a way to decrease those costs using just water, and it doesn't involve a swamp cooler or increasing the humidity within your home. One of the issues with central air conditioning units is the fact that during the times when you need it the most, the condenser unit, which sits outside the home, is forced to use the hot outside air to cool off the refrigerant. This leads to a harder-working AC unit and increased power consumption, which in turn translates into higher costs. However, by pre-cooling the immediate area around the condenser unit with a fine mist of water, AC units can run more efficiently, which reduces both power consumption and costs. Mistbox, which promises a quick and easy 5-minute installation, along with a set-it-and-forget-it computer-optimized control system, is a small solar-powered misting unit that mounts to the outside of the AC condenser, enabling the condenser to pull in cooler air for its operation during hot days. According to the company, this can reduce AC costs anywhere from 20-40%, right from the get-go, and can pay for itself within the first season of use. Here's how it works: Because the water mist merely cools the outside condenser unit, it doesn't enter the home's air supply, so humidity levels won't rise inside the home (which might be a boon in arid regions, but is completely undesirable in humid areas). And the company says that because the mist from the units is a 'fine spray' and the unit only runs when conditions require it (based on the temperature settings for the unit), "not much water is used," amounting to just pennies per day. Mistbox retails for $399, and in the US, qualifies for the 30% residential energy tax credit. Find out more at Mistbox.