The Aprilaire ARN25K Radon Mitigation Kit is a white, wall-mounted thermostat with a programmable schedule for 1 week. It features ambient light sensor technology and can be controlled through an app. This unit is designed for homes up to 2500 sq. ft., making it suitable for larger spaces. The Aprilaire ARN25K is a reliable and efficient option for maintaining a comfortable temperature while also helping to reduce radon levels in your home.