A Chicago winter is a long runtime. At O’Hare, a typical January still averages a high near 31°F and a low near 17°F, and the 1991–2020 climate normals include about six or seven nights a year at or below zero. Add a 10 to 15 mph wind off the lake and the house loses heat through every gap it has. Preventive maintenance is how you find out, in October, whether the heating system can do that work.
Zima HVAC maintains furnaces, boilers, water heaters, and the air equipment that shares the same house. We are in Mundelein, and the homes we see around Lake County live in this climate even when they sit well back from the shoreline.
The furnace, while it is still easy to get to
Most forced-air homes here heat with gas. A fall visit covers the heat exchanger, burners, igniter, safety controls, blower, and the intake and exhaust on a high-efficiency furnace. Those plastic vent pipes are easy to bury in a drift or pack with frost once the wind comes off Lake Michigan. A filter that was fine in September is often loaded by the time the fan starts running all evening. A clean filter is the cheapest way to keep airflow up and the heat exchanger in its designed temperature range.
We also look at the flue on older atmospheric furnaces. A bird nest or a deteriorated liner is a carbon monoxide problem, and winter is when that furnace runs. The tune-up is the inspection, plus a combustion check, before the season depends on it.
Boilers and radiant heat
If the house has radiators or in-floor tubing, the heating plant is a boiler, and it wants its own visit. Burners, the heat exchanger, the circulator, the expansion tank, and the relief valve are the pieces that fail quietly and then fail completely on a below-zero night. Homes around Chicago still have a lot of this equipment, and it rewards a November appointment more than a January emergency call. The boiler checklist is covered in our pre-winter boiler tune-up.
Dry air is part of the same system
Lake-effect cold is dry once it gets indoors and heats up. A whole-house humidifier only helps if the water panel is clean and the drain is open. A neglected humidifier grows scale, then mold, then a musty smell the furnace blows through every room. Winter maintenance includes that pad, the solenoid, and a setting that matches the outdoor temperature so the windows do not run with condensation.
Put the air conditioner to bed in the same trip
The outdoor condenser just spent a humid Chicago summer moving moisture, which is harder work than the thermostat temperature suggests. Fall is the time to wash the coil, confirm the disconnect, and leave the top of the unit open to the air so a cover does not trap moisture against the fins. Book the cooling tune-up for spring at the same time. May fills up once the first hot week hits the inland suburbs. What that summer actually does to the equipment is in our note on Chicago cooling season.
A short report beats a surprise
You should leave the visit with a clear list: what is sound, what is wearing out, and what can wait. That is more useful than a generic promise that the system is “good.” Chicago weather will test the weak part. Better to name it while the temperature is still in the 40s.
Call Zima HVAC at (847) 323-8314 to schedule winter maintenance. We are at 1917 McRae Ln, Mundelein, and we work across Lake County.