A filter assembly for an air conditioner unit includes a filter frame defining a plurality of attachment features for engaging a plurality of mounting features defined on an inlet frame of a cabinet of the air conditioner unit to secure the filter frame over the indoor inlet. A filter screen is attached to the filter frame for filtering a flow of air through the indoor inlet and the filter frame defines a mounting bracket for a secondary air filter.

A single-package air conditioning appliance includes a housing defining an outdoor portion and an indoor portion. An outdoor heat exchanger assembly is disposed in the outdoor portion. The outdoor heat exchanger assembly includes an outdoor heat exchanger and an outdoor fan. An indoor heat exchanger assembly is disposed in the indoor portion. The indoor heat exchanger assembly includes an indoor heat exchanger and an indoor fan. A compressor is in fluid communication with the outdoor heat exchanger and the indoor heat exchanger to circulate a refrigerant between the outdoor heat exchanger and the indoor heat exchanger. The single-package air conditioner unit also includes a make-up air module. The make-up air module extends between the outdoor portion of the housing and an outside of the housing. The make-up air module includes a plurality of make-up air fans.

A single-package air conditioning appliance includes a housing defining an outdoor portion and an indoor portion. An outdoor heat exchanger assembly is disposed in the outdoor portion. The outdoor heat exchanger assembly includes an outdoor heat exchanger and an outdoor fan. An indoor heat exchanger assembly is disposed in the indoor portion. The indoor heat exchanger assembly includes an indoor heat exchanger and an indoor fan. A compressor is in fluid communication with the outdoor heat exchanger and the indoor heat exchanger to circulate a refrigerant between the outdoor heat exchanger and the indoor heat exchanger. The single-package air conditioner unit also includes a make-up air module. The make-up air module extends between the outdoor portion of the housing and an outside of the housing. The make-up air module includes a plurality of make-up air fans.

An air purifier is provided. The air purifier includes a plurality of filters, a driving unit configured to individually move the plurality of filters, and a processor configured to control the driving unit so that at least one of the plurality of filters is disposed in an air passage in the air purifier according to an air state.

An intake hood system for a heating, ventilation, and/or air conditioning (HVAC) unit includes an intake hood having an inlet configured to receive an air flow into the intake hood, a first support configured to engage a first end of an air filter, and a second support configured to engage a second end of the air filter, where the first support is configured to align with a boundary of the inlet. The intake hood system also includes a lock bar configured to couple to the intake hood while abutting the first support and the second support to secure the air filter within the intake hood.

An air conditioning appliance or a make-up air (MUA) assembly may include an intake conduit and a secondary air duct. The intake conduit may be attachable to a housing of the air conditioning appliance. The intake conduit may define an intake passage upstream from the indoor inlet. The intake conduit may further define a secondary inlet upstream from the intake passage to permit air thereto. The secondary air duct may extend from the intake conduit outside of the housing upstream from the secondary inlet to direct air thereto.

An air conditioning appliance or a make-up air (MUA) assembly may include an intake conduit and a secondary air duct. The intake conduit may be attachable to a housing of the air conditioning appliance. The intake conduit may define an intake passage upstream from the indoor inlet. The intake conduit may further define a secondary inlet upstream from the intake passage to permit air thereto. The secondary air duct may extend from the intake conduit outside of the housing upstream from the secondary inlet to direct air thereto.

A gas sensing system for an air conditioner unit is provided. The air conditioner unit includes a bulkhead that divides a cabinet into an indoor portion and an outdoor portion, and a compressor circulates refrigerant through a sealed system. An electrically protected housing is positioned within the indoor portion and defines a sensor enclosure for receiving a gas sensor for measuring a gas concentration of leaked refrigerant within the sensor enclosure. The housing includes vent apertures to permit leaked refrigerant to enter the sensor enclosure while the vent apertures are covered by filters to prevent contaminants from entering the sensor enclosure.

A gas sensing system for an air conditioner unit is provided. The air conditioner unit includes a bulkhead that divides a cabinet into an indoor portion and an outdoor portion, and a compressor circulates refrigerant through a sealed system. An electrically protected housing is positioned within the indoor portion and defines a sensor enclosure for receiving a gas sensor for measuring a gas concentration of leaked refrigerant within the sensor enclosure. The housing includes vent apertures to permit leaked refrigerant to enter the sensor enclosure while the vent apertures are covered by filters to prevent contaminants from entering the sensor enclosure.

A ventilation air conditioning structure including a room that has a floor portion to a fourth wall portion, a first wall portion to be a building outer wall in which an air supply opening is formed in a vicinity of a third wall portion, and an air exhaust opening that is formed in a vicinity of the fourth wall portion. The ventilation air conditioning structure also includes an air conditioner that is disposed inside the room and where at least one of air sending openings of a room interior unit is capable of sending air in a direction of a second wall portion, and an external-air conditioner that is disposed outside the room. The external-air conditioner includes heat exchangers that are incorporated in a refrigerant circuit of the air conditioner via a branched pipe that is branched from a refrigerant piping and a casing that houses the heat exchangers.