Home energy audit in Illinois: free options, costs and what to expect

Free and low-cost options in Illinois

• Ameren Illinois customers: a FREE Home Energy Assessment is available to income-qualified households in single-family homes that heat with gas or electricity from Ameren Illinois, or Ameren electric customers who heat with propane. You may qualify for upgrades like insulation and air sealing at little to no cost, plus free installation of LED lighting, faucet aerators and an advanced power strip. Renters in a single-family home or duplex can apply with the owner’s consent, and the work is done by an Ameren Program Ally contractor (Ameren Illinois).
• Don’t qualify? Ameren says insulation discounts and product rebates are still available (Ameren Illinois), and its online marketplace sells discounted energy-saving products (Ameren Illinois).
• ComEd customers: ask ComEd about its home energy savings programs for your type of home.
• Income-eligible households anywhere in Illinois: the Illinois Home Weatherization Assistance Program can fund air sealing, insulation, HVAC and water heater repair or replacement, and more, up to $20,000 per home for energy-related work. Households at or below 200% of the federal poverty level, or LIHEAP clients in the last 12 months, can qualify. See our Illinois heating bill help guide.

What happens during a professional audit

• Blower door test: a powerful fan in a doorway lowers the pressure inside so the assessor can find air leaks. DOE says to make sure they use a calibrated blower door, which measures how much air leaks, not just where (DOE).
• Infrared scan: a thermal camera shows warm and cool spots in walls, roofs and around windows and doors (DOE).
• A report: afterward you should get a report of findings and ideas for improvements. DOE says you may only need to air seal small gaps or add attic insulation, or bigger upgrades may be cost-effective (DOE).

How to get the most from it

• Use a certified assessor. DOE says to check with your electric or gas utility, your state or local weatherization office, or ENERGY STAR (DOE).
• Before the visit, list problems like drafty rooms or condensation, and have recent energy bills ready (DOE).
• Ask about Home Performance with ENERGY STAR. DOE says those programs have contractors’ work checked by third parties (DOE).
• Look up rebates for the upgrades with the ENERGY STAR Rebate Finder.

Try a free do-it-yourself check first

• Paper test: close a door or window on a sheet of paper. If you can pull it out without tearing, air is leaking (DOE).
• Smoke test: on a cool, windy day, close windows and doors, turn on exhaust fans, and pass a lit incense stick around likely leak spots. Smoke that moves means a leak (DOE).
• Attic insulation: if the insulation is level with or below the floor joists, you probably need more (ENERGY STAR). Don’t disturb vermiculite insulation, a gray, pea-size flaky mineral that may contain asbestos, unless a lab has tested it (ENERGY STAR).

What about the federal tax credit?

The federal Energy Efficient Home Improvement Credit used to cover up to $150 for a home energy audit, but the IRS says it only applies to improvements made through December 31, 2025 (IRS, IRS FAQs). Check with a tax professional about your own situation.

Comparing solar options? See our community vs. rooftop solar guide, or our HVAC guide if your audit flags your furnace or AC.