An air-conditioning apparatus for air conditioning indoor environments has a containment structure having a casing delimiting a first compartment and a second compartment. A pellet stove configured to operate in heating mode and provided with a first duct for movement of combustion air in input to the pellet stove is housed inside the first compartment. A monoblock portable heat pump configured to operate in heating and/or cooling mode and provided with a second duct for movement of heated air in output from the monoblock portable heat pump is housed inside the second compartment.