Chicago's brutal winters force residents to seal homes tighter than almost anywhere in the country. You weatherstrip doors, install storm windows, and caulk every gap to keep heating bills manageable when wind chills hit 20 below. Modern energy efficiency upgrades like spray foam insulation and high-performance windows reduce air infiltration to near zero. That saves money but eliminates natural ventilation that once diluted carbon monoxide from minor leaks. Older Chicago homes were drafty by design. Fresh air leaked in through gaps and cracks, preventing dangerous gas buildup. Today's airtight homes trap carbon monoxide if combustion appliances malfunction or vent improperly.
Chicago's dense urban neighborhoods create unique carbon monoxide risks. Row houses, two-flats, and courtyard apartments share walls and sometimes share vents. A carbon monoxide leak in one unit can migrate through walls into neighboring spaces. Basement furnaces in multi-unit buildings pull combustion air from shared mechanical rooms where other equipment exhausts. Understanding these interconnected systems requires local experience. National chain companies send technicians who learned HVAC in suburban sprawl with detached single-family homes. They miss the complexity of Chicago's urban housing stock. Local HVAC professionals grew up working on these buildings and understand how they breathe.
