From The Manufacturer:
"Big Ass Fans are the highest quality, most meticulously engineered HVLS fans on the planet. HVLS stands for High Volume / Low Speed, meaning Big Ass Fans move a lot of air with their size (which is up to 24-ft. in diameter), not speed. Moving at a low speed means less energy used for operation, translating into more energy savings for you. And Big Ass Fans aren’t just for the warmer months. Big Ass Fans can save you money and keep you comfortable year-round.."