At Amazon, get this Vivosun Quiet Register Booster Fan for $20. It’s the best price we could find by $45. A built-in temperature probe and LCD controller start the fan automatically at heating or cooling thresholds you set, and it is rated at 18 dB. It is designed for wall or floor registers and is not recommended for ceiling mounting. Shipping is free for Prime members. Buy Now at Amazon
Features
Fits 4″ x 10″ register openings 10 adjustable fan speeds Programmable LCD controller w/ temperature probe that runs the fan at preset heating or cooling thresholds 18 dB noise level, 1,800 rpm max speed Aluminum frame w/ thermoplastic housing Includes a 12-ft. power cord
