HVAC in Pennsylvania is a heating season that is not optional, plus summers humid enough to make upper floors miserable. Rows often still run on radiators and a boiler, with a window unit in the sash. Hill houses and detached houses may have a furnace, a boiler, or both generations in one basement. Philadelphia rowhouses are not Pittsburgh houses on hills, and the basement you are standing in is the proof. No heat is the call to make now. Weak cooling in a July row house is a real call too.
Name the machine and the symptom. Whole building cold, or one radiator. A furnace that will not stay lit. A condenser crammed into a tiny row yard, or a long leaky duct run. Filters, a blocked return, and a flue that does not draft can imitate a dead plant. Ask what gets ruled out. In a row, the boiler may serve more than one household. On a hill, the equipment may sit in a basement that takes water from the slope. Say if it has been wet.
The shape changes the install. A row has no side yard for a condenser, so the outdoor piece ends up on a roof, in a rear slit of ground, or not at all. A hill house has outdoor space and a grade problem: equipment, lines, and condensate have to live with freeze and with water running at the foundation. Steam or hot water is not forced air. Do not let the call assume ducts you do not have. Say radiator or register in the first minute.
If replacement is the question, say the fuel and the type. Ask whether indoor and outdoor equipment are matched when cooling is part of it. Ask about the flue, combustion air, and a condensate line that can freeze. A checkup and a no-heat emergency are different appointments. Say whether you are cold tonight, and whether a neighbor on the stack is cold too. That last fact is a row question more than a hill question.
Bring the house shape with the equipment. HVAC in Pennsylvania is a boiler in a row or a furnace in a hill basement, and the season you are actually in. Call the number on this page.