HVAC in Pittsburgh has to finish a real winter in a house the wind can find. Furnaces and boilers sit in basements that are often walk-out on the downhill side and buried uphill. That basement may be damp. Lines and ducts run through a building that is not a simple box. Summers are humid in the valleys, so cooling is wanted, but no heat is the emergency. Say furnace or boiler, and say whether you have heat tonight.
Symptoms need the hill in them. A burner that drops out, radiators or registers that never catch the top floor, a condensate line that froze, a flue that drafts badly when the valley wind hits the chimney. Filters and blocked returns matter if you have ducts. Many older houses have radiators instead. Do not invent ducts. If the lower level is wet, say whether the equipment has been in water. Combustion air on a tight, buried basement wall is a fair thing to mention if the plant is starved when everything is closed.
Replacement has to fit the slope. An outdoor unit needs a pad that is not in the path of water off the hill and not hanging on a grade that washes out. Line sets and drains have to survive a freeze. Attic ducts in a cold roof make a furnace look weak. Ask what was checked before the whole system is condemned: filter, flue, condensate, the obvious failures that mimic a dead machine. If only the rooms on the windward side suffer, say that. The windows may be helping the problem.
Say the fuel and the age in plain words if you know them. Say radiator or register. Ask about matching equipment if cooling is being added to a house that never had it. A checkup is not a no-heat call. If older people or children are in a house with no heat, say that immediately. Steps and tight streets do not change the urgency. They change how the visit happens.
This is a hill basement and a winter that keeps its word. HVAC in Pittsburgh starts with the plant you have and whether it is running. Call the number on this page.