After 60+ hours of research and reviewing, we can confidently say that the best thermostat lock box on the market right now is the Emerson F29-0222. This lock box is simple, standard for lock boxes, but the sturdy metal construction makes it reliable and recognizable. This is the regular beige-enamel metal lock box that we have all seen at one point or another. This box is vented correctly to make sure your thermostat works as it’s supposed to, without giving off a false reading due to a lack of airflow. All boxes from this model are keyed differently, which is another layer of safety. If you want a lock box that will keep your thermostat out of sight and discourage unwanted tampering, this is the box for you.