Illinois does not set one minimum legal temperature for tenants statewide. The legal temperature for tenants in Illinois depends on where you live: Chicago requires at least 68°F during the day and 66°F at night from September 15 through June 1, Evanston and Oak Park set their own numbers, and tenants in cities without a heating ordinance fall back on the implied warranty of habitability, which requires adequate heat without naming a degree.
Chicago’s Required Indoor Temperatures
Chicago’s Heat Ordinance (Municipal Code Section 14X-8-803) is the most specific rule in the state. The heating season runs September 15 through June 1. In a building with central heating and no central cooling, the landlord must keep every unit at a minimum of 68°F from 8:30 a.m. to 10:30 p.m. and 66°F from 10:30 p.m. to 8:30 a.m.1City of Chicago. Chicago Heat Ordinance
Buildings where one system handles both heating and cooling generally follow the same 68°F/66°F standard, though the minimum drops to 64°F at all hours during narrow transition windows at the start and end of the season. In buildings where each unit has its own heating equipment, the equipment itself must be capable of holding 68°F in typical Chicago winter conditions, and any failure during the heating season is a violation on its own.
Fines run $500 to $1,000 per day, per violation.1City of Chicago. Chicago Heat Ordinance
Evanston, Oak Park, and Other Suburbs
Several suburbs run their own heating ordinances with their own numbers and calendars. Check your city’s municipal code if you rent outside Chicago.
Evanston requires landlords who provide heat to maintain at least 68°F in all habitable rooms, bathrooms, and toilet rooms from September 15 through June 1. Space heaters, whether portable or permanently installed, are not allowed as the primary heat source for any unit.2City of Evanston. Heat Requirements
Oak Park requires adequate heat in all habitable rooms, bathrooms, and toilet rooms from September 15 through May 15. The minimum is 68°F from 6:30 a.m. to 11:00 p.m. and 65°F from 11:00 p.m. to 6:30 a.m.3Village of Oak Park. Property Standards
Oak Park’s heating season ends two weeks earlier than Chicago’s, and its overnight minimum is one degree lower. If your municipality is not listed here, call the local building department or code enforcement office and ask whether a heating ordinance applies to your unit.
If Your City Has No Heating Ordinance
Illinois courts recognize an implied warranty of habitability in every residential lease, established by the Illinois Supreme Court in Jack Spring, Inc. v. Little in 1972. Your landlord must keep the property fit to live in, and functioning heat is part of that obligation whether or not the lease says so. A unit that drops to dangerously low temperatures during an Illinois winter is not livable, and you can pursue legal remedies even without a local ordinance.
The downside of the warranty is that it gives you no specific number. Courts ask whether the heat provided was reasonable or adequate under the circumstances. That is why local ordinances, where they exist, are a stronger tool: they put exact temperatures, time windows, and penalties on the record.
Senior Housing: The One Statewide Number
Illinois does have a statewide statute with specific temperatures, but it applies only to residential rental properties restricted to tenants aged 55 or older. Under 765 ILCS 705/20, landlords of qualifying senior housing with a building-wide heating or cooling system must meet these standards:4Illinois General Assembly. 765 ILCS 705/20 – Heating and Cooling Standards
- Heating season (October 1 through May 31): at least 68°F between 6:00 a.m. and 10:00 p.m. when the outdoor temperature falls below 55°F, and at least 62°F between 10:00 p.m. and 6:00 a.m.
- Cooling season (June 1 through September 30): cooling systems must operate when the heat index exceeds 80°F.
If a 55+ property lacks a building-wide cooling system, the landlord must provide at least one indoor common gathering space with free, working cooling that all tenants can access. Properties without any such common space are exempt from the cooling requirement. The statute took effect January 1, 2024.
Air Conditioning Is Not Required
Outside of 55+ housing, no Illinois law requires landlords to provide air conditioning. Cooling is not treated as essential under the implied warranty of habitability for general tenants, and a landlord can legally rent you a unit with no AC at all.
If your lease includes air conditioning, or the unit came with an AC when you moved in, the landlord is responsible for keeping it working. A broken AC the landlord promised you is a breach of the lease, but it generally does not let you withhold rent or declare the unit uninhabitable.
What to Do When the Heat Fails
Document the Temperature
Before taking any legal step, build a record. Take timestamped photos or short videos of your thermostat showing the indoor temperature along with the date and time. Log the outdoor temperature from a weather source for the same period. Keep copies of every message to the landlord. If you have a standalone thermometer, place it three feet from an exterior wall and three feet above the floor, the measurement standard Evanston uses and a reasonable benchmark elsewhere.
Send Written Notice
Put the complaint in writing. Describe the problem, list the dates and times when the temperature was inadequate, and tell the landlord what you expect them to fix. Send it by certified mail or another method that proves delivery. Almost every legal remedy below requires proof the landlord received written notice and failed to act.
File a 311 Complaint in Chicago
Chicago tenants can file a heat complaint through 311 by phone, online, or the CHI 311 app. The Department of Buildings enforces the Heat Ordinance and will inspect the unit.5CHI 311. Chicago Heat Ordinance The daily fine tends to move repairs faster than a letter alone.
Repair and Deduct
Under the Illinois Residential Tenants’ Right to Repair Act, if your landlord fails to make a required repair within 14 days of receiving your written notice, you can hire someone to fix the problem and deduct the cost from your next rent payment. The repair cost cannot exceed the lesser of $500 or one-half of your monthly rent. In emergencies that threaten health or safety, or that would cause irreparable harm to the unit, you do not have to wait 14 days. After the repair, submit the paid bill to your landlord along with the name, address, and phone number of the person who did the work.6Illinois General Assembly. 765 ILCS 742 – Residential Tenants Right to Repair Act
The $500 cap makes this remedy a fit for a broken thermostat or a faulty igniter, not a furnace replacement.
Withhold Rent (Chicago RLTO)
Chicago tenants covered by the Residential Landlord and Tenant Ordinance may have the right to withhold rent when the landlord fails to supply heat.1City of Chicago. Chicago Heat Ordinance This is the strongest tool and the riskiest. Withholding without following the proper procedure invites a nonpayment eviction, and you will have to convince a court the withholding was justified. Keep the withheld rent in a separate account; spending it undermines your position.
The RLTO does not cover every Chicago unit. The most common exemption is owner-occupied buildings with six or fewer units. If that is your building, RLTO remedies do not apply, but you still have rights under state law and the Heat Ordinance itself.
Terminate the Lease
Under the Chicago RLTO, if heat is not restored within 72 hours after the landlord receives your written notice, you may terminate the lease. You then have to vacate within 30 days after that 72-hour window closes. Outside Chicago, lease termination for failure to provide heat is harder to establish and usually requires showing constructive eviction, meaning the conditions became so severe you were effectively forced out. Talk to an attorney before terminating. Getting this wrong can leave you on the hook for the remaining rent.
Federally Subsidized Housing
If you receive a Housing Choice Voucher (Section 8) or live in public housing, federal standards apply on top of state or local rules. Under HUD’s Housing Quality Standards, every unit must have a safe heating system in proper operating condition capable of providing adequate heat to each room. Unvented heaters that burn gas, oil, or kerosene are prohibited.7GovInfo. 24 CFR 982.401 – Housing Quality Standards
HUD guidance for public housing sets a minimum of 68°F when the housing authority controls the heat, and requires heating equipment capable of reaching 68°F when the tenant controls it. Indoor temperatures should never drop below 55°F. Report heating problems to your local Public Housing Agency, which can withhold housing assistance payments from the landlord until repairs are made.
Help Paying for Heat
If you are struggling with heating bills, or your landlord is not supplying heat, the Low Income Home Energy Assistance Program (LIHEAP) may help. The federal program, administered in Illinois by the Department of Commerce and Economic Opportunity, pays toward heating bills, prevents shutoffs, and can fund emergency repair or replacement of heating equipment.8Administration for Children & Families. Low Income Home Energy Assistance Program (LIHEAP)
For the 2026 program year, eligibility is set at 60% of state median income. A single-person household qualifies with annual income at or below $39,979; for a family of four, the threshold is $76,884. You may still qualify even if heat is included in your rent. Apply online at helpillinoisfamilies.com during your application month, or contact your local administering agency.9Illinois DCEO. How to Apply – Utility Bill Assistance
One safety note worth emphasizing while you wait on repairs: never use an oven, stovetop, or charcoal grill to heat your home. These are leading causes of residential fires and carbon monoxide poisoning during heating emergencies.10USFA FEMA. Heating Fire Safety