A disgruntled customer is suing Nest, claiming that the company’s popular line of home thermostats are defective because they heat up and fail to measure a room’s actual temperature. In a complaint filed this week in San Jose, Maryland man Justin Darisse said he bought the device on Amazon for $249.99 after seeing Nest promotional videos that suggested it would save him money, but that faulty temperature readings caused him to actually pay more for energy costs: “Nest’s base and faceplate heat up, which causes Nest’s temperature reading to be from two to ten degrees higher than the actual ambient temperature in the surrounding room. This defect prevents the thermostat from working properly. As a result, Nest users do not experience the advertised energy savings.”