Abstract: Methods and systems for monitoring the condition of a new air filter installed in an HVAC system are disclosed. In one example, an input that indicates a new air filter has been installed may be accepted, and in response, the HVAC system may be automatically operated in an air filter verifying mode, in which the fan of the HVAC system is activated to drive air through the new air filter. While in the air filter verifying mode, a measure related to an amount of flow restriction presented by the new air filter may be received. A status of the new air filter may be determined based, at least in part, on the received measure related to the amount of flow restriction presented by the air filter of the HVAC system. Once the status of the new air filter is determined, an indication may be displayed on a display, which may communicate the determined status of the new air filter to a user.

Abstract: Sensor offsets for an air filter monitor installed in an HVAC system may be determined by measuring a sensor offset differential pressure value across an air filter when substantially no air flow exists through the air filter. The sensor offset differential pressure value obtained at or near zero flow may represent the sensor offset for the air filter monitor. The sensor offset differential pressure value may be used to compensate an un-compensated differential pressure value obtained during flow conditions.

Abstract: A clean air filter may be used to set an air filter change threshold value for an air filter monitor installed in an HVAC system. The air filter change threshold value may be used to determine a status of an air filter (e.g., clean or dirty).

Abstract: Methods and systems for monitoring an air filter installed in an HVAC system may include operating the HVAC system in an air filter monitoring mode such as, for example, a fan only mode, and measuring, for example, a differential pressure across the air filter when the HVAC system is operating in the air filter monitoring mode. The method may include evaluating a status of the air filter using, for example, the measured differential pressure value, and in some cases, display the status on a display of an HVAC controller.

Abstract: The disclosure relates generally to steam humidifiers with an auto-cleaning feature, and more particularly, to steam humidifiers that include an auto-cleaning feature for automatically cleaning impurities and/or other byproducts from the steam humidifier while still operating the humidifier in a relatively efficient manner. In some illustrative embodiment, this may be accomplished by providing some level of flexibility of when an auto-cleaning routine is initiated and performed. For example, tank flushing may be initiated and performed preferentially during non-heating states of the steam humidifier, which may potentially decrease down time and increase attainable output capacity and efficiency of the steam humidifier.

Abstract: Systems and methods for the auxiliary stage control of multistage thermostats are disclosed. An illustrative multistage thermostat for a multistaged HVAC system installed within a building or structure can include a processor having a control algorithm adapted to operate the thermostat in either a normal mode for achieving rapid temperature changes within the building or structure or an economy mode for conserving energy usage. In the economy mode of operation, the thermostat can be configured to determine a target time for achieving a temperature setpoint by either delaying or suppressing activation of the system's auxiliary stage. The target time can be adjusted in part based on the past usage characteristics of the auxiliary stage, the behavior of the user, and/or the progress of the primary stage in achieving the setpoint change without operating the auxiliary stage.

Abstract: A thermostat system having multiple and individual schedules. For instance, a user may have different schedules and setpoints for heating and cooling. An appropriate schedule combining individual schedules may be automatically selected based on a system configuration. Schedule control may involve manual changeover from one schedule to another or automatic changeover relative to the schedule combining schedules. The thermostat system may be programmable. Also, there may be a system switch mode, for example, between heat and cool, where the schedules of either may be edited. Scheduling may be menu and option key driven.