Instruct: Classify the given review into positive or negative sentiment.
Query: Works perfectly

You can use to control the temperature in a room when either heating or cooling it. I use it to control a fan to cool off our bedroom in the evenings in the spring and fall when the outside air is cool but the room gets hot from the sun during the day. I also use it to keep the nursery at 72 deg all the time, while the rest of the house gets cooler at night because we have the furnace thermostat programmed that way to save energy.