Illinois Air Duct Pros guide
Radiators, Central Air or Forced Air? Does Your Illinois Home Have Ducts?
Not every Illinois home has heating ducts. About 76% of Illinois homes heat mainly with a furnace, which moves air through ducts, but about 11% use a steam or hot-water boiler that sends heat through pipes to radiators or baseboards. Before booking duct cleaning, find out which system you have, whether central air adds separate ductwork, and, in condos and multi-unit buildings, who is responsible for shared parts.
Updated October 19, 2026Sources listed below
Why this question comes up in Illinois
In the U.S. Energy Information Administration's 2020 Residential Energy Consumption Survey, about 76% of Illinois homes used a furnace as their main heating equipment and about 11% used a steam or hot-water boiler.
Housing age and building type add to the confusion. Census survey data show about 39% of Chicago's housing units were built in 1939 or earlier, and about seven in ten are in buildings with two or more units. In older and shared buildings, heating and cooling equipment may have been added or changed over time, and the resident may not know what's behind the walls.
Sources: U.S. EIA: 2020 RECS, Highlights for space heating in U.S. homes by state; U.S. Census Bureau: ACS 2024 1-year, Table DP04 (Illinois, Chicago)
How to tell which system you have
The U.S. Department of Energy explains the basic difference: a furnace heats air and uses a blower motor and air ducts to distribute it, while a boiler heats water to provide hot water or steam that is distributed through a series of pipes. A few quick checks usually tell you which you have:
- Radiators, or hot-water baseboard units fed by pipes, usually point to a boiler rather than ducts.
- Floor, wall or ceiling grilles that blow warm air in winter point to a furnace and ductwork.
- Grilles that blow only in summer, in a home with radiators, suggest ductwork for central air alone.
- Window or wall air conditioners plus radiators can mean there are no ducts to clean.
If you live in a condo, two-flat or apartment building
About 26% of Chicago's housing units are in buildings with two to four units and more than a quarter are in buildings with 20 or more, according to Census survey data. In these buildings, responsibility can be split: a unit owner may control the ducts inside the unit while the association controls shared shafts, roof equipment and exterior terminations.
Before requesting duct or dryer vent cleaning, ask your association or building manager what you're responsible for and whether access to common areas or the roof is allowed. Then tell us which unit the request covers and what you learned.
Source: U.S. Census Bureau: ACS 2024 1-year, Table DP04 (Illinois, Chicago)
What duct cleaning can and can't do
If your home does have ducts, EPA recommends cleaning only as needed: for example, when ducts are clogged with excessive dust and debris or particles are actually released into the home, when there's evidence of rodents or insects, or when there's substantial visible mold growth inside sheet-metal ducts. EPA also says duct cleaning has never been shown to actually prevent health problems.
Cleaning is not HVAC repair, and it doesn't include chemical treatment by default. EPA notes that research hasn't demonstrated the effectiveness of biocides and sealants in duct cleaning. If a boiler, furnace or air conditioner needs service, that's a job for an HVAC technician.
Source: U.S. EPA: Should You Have the Air Ducts in Your Home Cleaned?