Stroll through almost any outdoor shopping area in the heat of summer, and you’ll see retail stores with open doors while the A/C is blasting. It’s a practice that presumably lures customers into the store, but wastes excessive amounts of energy.

According to the Natural Resources Defense Council, nearly 20 percent of stores nationwide leave their doors open with the air conditioning set on a low temperature. Generation 180, a non-profit organization, is working to close the doors by empowering customers to help reduce energy waste through its Keep It Cool campaign. Customers can participate by using Facebook Messenger to tag a store with its doors open (or closed). Then the campaign will reach out to ask businesses to close their doors, or congratulate them on keeping them closed.

The average store with an open door wastes 4,200 kWh of electricity every summer and releases 2.2 tons of additional CO2 into the atmosphere, reports Generation 180. That’s equivalent to the pollution released by a semi-truck driving from New York, NY to Miami, FL.

The open-door practice also increases the risk of brownouts or blackouts because retail store doors are often propped open on the hottest summer days, when citywide energy demand is already peaking.

Learn how to participate and track the campaign’s nationwide progress at Keep It Cool