Abstract: Improved window HVAC housings and installation methods reduce unwanted heat transfer through the window areas in which the window-based HVAC equipment, such as air conditioners including heat pumps and fans, are installed. An insulating pane may be installed in lieu of or combination with a window in a wall, wherein the insulating pane is configured to pass a heat exchanger connector connecting heat exchangers on opposing sides of the insulating pane. A heat exchanger sleeve may be provided to pass the heat exchanger connector and may provide support for the connector and/or HVAC equipment. An interior or exterior housing portion may be provided. The interior housing portion may include an accessible front portion and HVAC support to support installed HVAC equipment. The exterior housing portion may be attached to the window frame, insulating pane, and/or interior housing and may be installed from inside the building.