Questions to ask before you hire an HVAC contractor in Chicago
In Chicago, heating is the job that matters most: long, cold winters with subzero snaps put real stress on furnaces and boilers, and a no-heat night can freeze pipes fast. Summers are shorter but humid, and many greystones, two-flats, and older bungalows still heat with steam or hot-water radiators and have no ducts for central air. Illinois has no statewide HVAC license, so in the city the question is whose City of Chicago general contractor license the job runs under, and whether your replacement even needs a permit. Use these questions to compare Chicago-area HVAC contractors on verified credentials, sizing for winter and summer, safe venting, and a written scope, not just who can come out today.
Questions to ask
1. Who is the licensed contractor on my job: do you hold a City of Chicago general contractor license (or the license my suburb requires), and can I see the number?
Why it matters: Illinois does not have a statewide HVAC contractor license (HVAC is not among the professions on the state’s IDFPR regulated-professions list), so HVAC licensing in the Chicago area is local. Inside the City of Chicago there is no separate HVAC trade license: the Chicago Department of Buildings requires a licensed general contractor (Class A through E, based on total project cost) on most mechanical permits, and an HVAC company that contracts directly with you generally needs that general contractor license itself, both for permitted work and for permit-exempt work such as an in-kind replacement, because the city treats permit-exempt building work as a regulated activity that requires the license (Chicago general contractor license). An HVAC company working as a subcontractor under someone else’s general contractor license does not need its own, which is why you should ask exactly whose license the permit will be pulled under and who is responsible for the work. Any new electrical circuit or disconnect (for a heat pump, mini-split, or condenser) is electrical work, which in Chicago requires a City of Chicago licensed electrical contractor (Chicago trade licensing). In suburbs such as Evanston, Oak Park, Skokie, Cicero, or Naperville, contractor registration rules vary by municipality, so check your own village or city. Verify the license on the City of Chicago Department of Buildings contractor license lookup (or your suburb’s list), and ask for a current liability insurance certificate.
2. Which technicians on my job hold EPA Section 608 certification, and are they trained on the newer A2L refrigerants?
Why it matters: Anyone who installs, services, or repairs equipment containing refrigerant must hold EPA Section 608 certification or work under the direct supervision of someone who does; the City of Chicago’s mechanical permit conditions repeat that requirement. Many newer systems sold since the federal refrigerant transition use A2L refrigerants (such as R-454B or R-32), which have their own handling and installation requirements. Ask who on the crew is certified, whether they have installed the refrigerant your proposed system uses, and how they will recover refrigerant from the unit they remove. If your central air still runs on R-22, ask plainly whether a repair still makes sense or whether replacement is the honest answer.
3. Will you run a Manual J load calculation for Chicago winters and humid summers, instead of matching the old unit’s size?
Why it matters: In Chicago, heating is usually the bigger load: the coldest nights can drop below zero, and many older bungalows, two-flats, and frame houses leak air and have little wall insulation. Summers are shorter but can be hot and humid. A Manual J (or equivalent) load calculation should account for local design temperatures, insulation, windows, air leakage, and where the ducts or pipes run, and you should get the results in writing. Oversized furnaces and air conditioners are common: they short-cycle, wear out sooner, create uneven rooms, and an oversized AC removes less moisture on muggy days. Ask how the proposed system will keep up during a deep cold snap and a July heat wave, and whether insulation or air sealing would let you buy smaller equipment.
4. Would a high-efficiency gas furnace, a cold-climate heat pump, or a dual-fuel system fit my home, and how will it heat on the coldest nights?
Why it matters: Most Chicago-area homes heat with natural gas, but cold-climate heat pumps and dual-fuel systems (a heat pump paired with a gas furnace as backup) are increasingly offered, and utility incentives sometimes favor heat pumps. Press on cold-weather performance. Ask for the manufacturer’s rated heating capacity at low outdoor temperatures, what backup heat is included (gas furnace or electric resistance strips), at what outdoor temperature the system switches to backup, and what electric strips would mean for your panel and your ComEd bill. If you keep gas, ask how the furnace’s efficiency (AFUE) and blower type affect comfort and operating cost under your gas rates from Peoples Gas, Nicor Gas, or North Shore Gas. A good contractor compares options for your house and explains the trade-offs; be wary of anyone who pushes one answer without looking at it.
5. My home has a boiler and radiators, or no ductwork at all. How will you handle heating, and what are my cooling options?
Why it matters: Many Chicago greystones, two-flats, and older bungalows heat with steam or hot-water boilers and radiators and have no ducts, so cooling has historically meant window units. If you have a boiler, ask whether the contractor regularly works on steam or hydronic systems, how they will check near-boiler piping, venting, the low-water cutoff or pressure relief valve, and the expansion tank, and whether a replacement boiler is sized from a heat-loss calculation or radiator survey rather than the old boiler’s rating (old steam boilers were often oversized). For cooling or heat-pump heating without ducts, ask about ductless mini-splits or small-duct high-velocity systems, where indoor heads and the outdoor unit would go, how line sets and condensate lines will be routed through masonry walls, and whether the system can heat on its own or is meant to supplement the boiler. In a multi-unit building, ask how the work affects other units and whether your building has boiler inspection requirements.
6. How will you check furnace or boiler venting, the chimney, and carbon monoxide safety, including vents that can get blocked by snow?
Why it matters: High-efficiency condensing furnaces and boilers usually vent through plastic pipe out a side wall, and in Chicago winters drifting snow and ice can block the intake and exhaust terminations or freeze a poorly routed condensate line, shutting the system down on a cold night. Ask where the vents will exit, how high above expected snow level, and how condensate will drain without freezing. When an old furnace that shared a masonry chimney is replaced with a side-vented unit, the remaining gas water heater can be left alone in an oversized chimney, which can cause poor draft and condensation; ask whether a chimney liner or other venting change is needed. Ask them to test for gas leaks and carbon monoxide and to confirm you have working CO alarms; Illinois’ Carbon Monoxide Alarm Detector Act requires an operating CO alarm within 15 feet of every room used for sleeping in each dwelling unit, with exemptions for homes that have no fuel-burning heat or appliances, no attached garage, and no nearby CO source (430 ILCS 135/10 and 135/20).
7. What will you check on ducts, humidity, and condensate, and how do you handle old materials that may contain asbestos?
Why it matters: In many Chicago-area homes the furnace and main ducts are in the basement, with some runs in attics or exterior walls of second floors that are hard to heat and cool evenly. Ask whether they will inspect and pressure-test the ducts and what sealing, balancing, or return-air fixes they recommend for rooms that are always too hot or cold. Winter air is very dry indoors, so ask whether a humidifier makes sense and how it would be maintained; in summer, ask how the AC’s condensate will drain and whether a pump or float switch is needed. Older basements and boiler rooms often have pipe insulation, duct wrap, or flue materials that may contain asbestos. Suspect material should be tested before anyone disturbs it, and in Chicago some asbestos work requires an Asbestos Project Notification with the Chicago Department of Public Health (Chicago DOB), so ask how they handle it.
8. Does my job need a City of Chicago or suburban permit, who pulls it, and is the inspection included?
Why it matters: In the City of Chicago, the Department of Buildings says a permit is not required to repair heating and cooling equipment, and in residential buildings up to four stories it is also not required to replace a boiler, furnace, or air conditioner in kind (same type, size, and shape). Changing the type of system, such as a furnace to a heat pump, adding a mini-split with a new hardwired electrical connection, or altering ducts or venting generally takes a permit with a licensed general contractor listed, and electrical work needs its own licensed contractor. Exceptions may not apply to Chicago Landmark properties or districts. Even when no permit is needed, the contractor generally still needs a Chicago general contractor license (see question 1). Suburbs such as Evanston, Oak Park, Skokie, and unincorporated Cook County follow their own rules. Ask the contractor to explain in writing whether your job needs a permit and why, who pulls it, and whether inspection fees are in the quote. Confirm your Authority Having Jurisdiction (AHJ) yourself if the answer sounds like it is only meant to save time.
9. Which ComEd, gas utility, or other efficiency programs might apply, and will you handle the paperwork?
Why it matters: Most of the Chicago area gets electricity from ComEd, while natural gas comes from Peoples Gas in the city, North Shore Gas in some northern suburbs, or Nicor Gas in much of the rest of northern Illinois. Each runs its own residential efficiency programs (ComEd, Peoples Gas and North Shore Gas, Nicor Gas), and those programs change, often yearly, with deadlines and equipment requirements such as SEER2, HSPF2, AFUE, or an AHRI certificate for the matched system. Some towns with municipal electric utilities, such as Naperville, may not be eligible for ComEd programs. Ask which programs the contractor participates in, which equipment ratings the rebate depends on, who submits the application and by when, and get any promised amount in writing as an estimate, not a guarantee. The federal Energy Efficient Home Improvement Credit (25C) ended for equipment placed in service after Dec. 31, 2025 (IRS), so a system installed in 2026 does not qualify for it; be wary of any quote that still counts a federal tax credit. Verify current rules directly with the utility before you sign.
10. What does the written estimate include: model numbers, venting, duct or piping work, electrical work, disposal, and a labor warranty?
Why it matters: A good quote lists the exact indoor and outdoor model numbers, efficiency ratings, thermostat, line set, pad or wall bracket, venting and any chimney liner, condensate drain or pump, duct or boiler piping changes, humidifier if included, electrical work for a heat pump or condenser, permit fees, and disposal of the old equipment. Ask how they handle surprises like a corroded flue, asbestos-suspect material, a cracked heat exchanger, or tight basement access, and require a stop-and-call change-order process before extra work. Get the manufacturer warranty and the contractor’s labor warranty in writing separately, and confirm who registers the equipment so the manufacturer warranty applies.
11. How do you handle no-heat calls during a cold snap and no-cooling calls in a heat wave, and can you give me recent Chicago-area references?
Why it matters: Losing heat during a Chicago cold snap is more than uncomfortable: pipes along exterior walls and in unheated spaces can freeze within hours, and older adults, young children, and pets are at risk, while summer heat waves can be dangerous too. Every HVAC company in the region gets slammed at once. Ask what response time looks like for existing customers during those surges, what after-hours and weekend rates apply, whether a maintenance plan actually moves you up the list, and what a fall tune-up includes before heating season. Then ask for two or three recent local references for similar homes, such as a boiler replacement in a two-flat, a furnace and AC in a bungalow, or a heat pump in a suburban split-level. References tell you about punctuality, cleanup, and whether the system was set up right the first time, which star ratings alone often miss.
Red flags
Quotes a replacement size over the phone or by matching the old furnace, boiler, or AC, with no load or heat-loss calculation.
Cannot tell you whose City of Chicago general contractor license (or suburban registration) the job is under, or which licensed electrical contractor will do the wiring.
Offers a lower price to skip a permit your job actually needs, or cannot explain why your job is exempt.
Vague about which refrigerant the new system uses or who on the crew is EPA 608 certified.
Pitches a heat pump without explaining cold-weather capacity, backup heat, and what electric strips need from your panel.
Ignores side-wall vent placement for snow, condensate freezing, an orphaned water heater in the chimney, or carbon monoxide checks.
Wants to rip out a boiler or radiators without explaining how the home will be heated and how the replacement was sized.
Disturbs old pipe insulation or duct wrap without talking about asbestos testing.
No model numbers, no venting, duct, piping, or electrical scope, and no written labor warranty on the estimate.
Promises a specific rebate or tax credit as guaranteed, or asks you to sign over a rebate you have not verified.
Get at least two written quotes for the same scope, with model numbers, efficiency ratings, and venting, duct or piping, and electrical work listed.
Ask each contractor to share their load or heat-loss calculation and explain how the system handles a deep cold snap and a humid heat wave.
Confirm your AHJ (City of Chicago, a suburban village or city, or unincorporated Cook County), whether your job needs a permit, and who pulls it and schedules the inspection.
Make sure you have working carbon monoxide alarms and ask for a combustion, venting, and chimney check on any gas furnace, boiler, or water heater.
Ask where side-wall vents and the outdoor unit will go relative to snow drifts, and how condensate will drain in winter.
Ask about asbestos testing before anyone disturbs old pipe insulation, duct wrap, or flue materials.
Check current incentives directly with ComEd and your gas utility (Peoples Gas, North Shore Gas, or Nicor Gas) before you sign.
Agree in writing on equipment placement, filter location, warranty terms, payment schedule, and a stop-and-call change-order process.
Keep the permit record (if any), warranty registrations, and final invoice for resale and future service.