Steam heat, one-pipe systems, and cooling that was added later
A large share of Brooklyn's heating load still runs on steam. One-pipe systems in Park Slope brownstones and Bay Ridge rowhouses come with failing air vents, waterlogged returns, banging risers, and boilers sized for a building that has since been split into three apartments. Diagnosing them over the phone is impossible, but qualifying them is not — knowing that a caller has radiators rather than registers already tells your dispatcher which technician can actually help.
Cooling is almost always a later addition. Window units, sleeve units cut into masonry, and ductless mini-split heads mounted wherever a line set could be run. Bensonhurst and Sheepshead Bay have a heavy concentration of condensers hung on rear walls and on flat roofs with limited access, which changes both the quote and the crew size before anybody drives out.