VentCool™ Whole House Fans replace warm/stale inside air with cool/fresh outdoor air. Fresh, cool nighttime air is brought in from outdoors to precool the house and its contents (thermal mass cooling). Free cooling is a great way to reduce energy costs, increase fresh air ventilation, and enhance indoor air quality. Our VentCool free cooling whole house fans are available in three series: Tahoe, Summit and Vista. All series feature models in a range of sizes and configurations.