The present invention provides apparatuses and methods for restricting access to a control unit in an environmental system based on a lock level. The control unit (e.g., a thermostat) is configured with a selected lock level, where each lock level is mapped to an associated set of features. A user is able to access any of the features from the associated set of features without entering a security sequence. Also, a feature parameter may be restricted in accordance with the activated lock level. The control unit may be reconfigured with a different lock level by an administrator only when a security sequence is entered. Also, features may be mapped by an administrator to a set of features when the control unit is operating in the locked state. When the control unit is operating in the unlocked state, all supported features can be accessed by a user.