HVAC in Indiana works both ends of the year, with a short pause between. Furnaces meet a real freeze. Cooling and sticky air arrive fast when summer sits on the attic. Newer houses may use a heat pump. Older ones often have a basement furnace and weak upstairs ducts. If the house is uncomfortable right now, say heat or cooling before you hunt a model plate.
A dead compressor is not the first guess. Choked filters, a crushed return in a basement, and a closed bedroom register imitate one. Attic ducts in new subdivisions bake in summer and bleed heat in winter if they were left loose. Ask what got ruled out. Combustion gear needs a clear flue. A furnace that short-cycles on the first cold night should not wait, because mild weeks here do not last.
Replacement follows the house. Windows, the attic, and duct size change the load. Matching the old cabinet because it fit the closet leaves the same hot upstairs. A new outdoor unit on an old indoor coil is not a matched system. Say whether the ducts run in a hot attic or a damp basement. A no-heat night does not wait for a polite season.
Humidity is the summer complaint people misname as temperature alone. The house can feel heavy while the thermostat thinks it has won. That can be airflow, a coil, or a system that short-cycles. Condensate lines clog in the humid stretch and then overflow into a ceiling or a basement floor. Outdoor units sit on clay that shifts, so a pad does not stay level by hope.
Say the town, the symptom, and whether every room fails or only the one over the garage. Clear snow off the outdoor unit if you can do it safely, then call. Do not open a gas compartment to poke around. Call the number on this page.