Heating and cooling questions, answered

Heating and furnaces

• Why is my furnace blowing cold air?

  Most of the time a furnace blows cold air because the thermostat fan is set to ON instead of AUTO, the filter is clogged, or the furnace has shut its…

• What furnace noises mean (banging, squealing, rattling, humming, clicking)

  Some furnace sounds are normal: a soft click when it starts, the whoosh of burners lighting and a low hum from the blower. Loud banging at startup,…

• How much does a new furnace cost in the Chicago suburbs?

  A complete gas furnace replacement in the Chicago suburbs typically runs about $5,500 to $11,000 installed in 2026, according to a local cost guide,…

• Why does my furnace keep turning on and off (short cycling)?

  A furnace that turns on and off every few minutes is short cycling. The most common causes are a clogged air filter, a thermostat in the wrong spot,…

• Do heat pumps work in Chicago winters?

  Yes. Modern cold-climate heat pumps keep heating well below freezing, and ENERGY STAR's cold-climate rating requires tested performance down to 5°F.…

• Do I need a permit to replace a furnace or AC in the northwest suburbs?

  In most northwest suburbs, yes. In Schaumburg, replacing a furnace, air conditioner or water heater requires a permit, but it's a quick Express…

• ComEd and Nicor Gas rebates for furnaces, AC and heat pumps

  In 2026, Nicor Gas offers $150 to $225 rebates on furnaces rated 95% AFUE or higher ($200 to $275 when bundled with a smart thermostat) and $350 on…

• No heat? 8 things to check before you call

  Before calling for service, check the thermostat mode and batteries, the furnace power switch and breaker, the air filter, the furnace door, the…

Air conditioning and heat pumps

• Why is there ice on my AC lines or coil, and what should I do?

  Ice on your AC lines or indoor coil almost always means the coil is getting too cold, usually from weak airflow (a dirty filter or blocked vents) or…

• Why is my AC running but not cooling?

  When your AC runs but the house stays warm, the most common causes are a thermostat set wrong, a clogged air filter, a tripped breaker for the…

• R-454B and the refrigerant change: what it means for your R-410A or R-22 system

  New central ACs and heat pumps now use lower-impact refrigerants such as R-454B because of EPA rules under the AIM Act. If you have an R-410A system,…

• Should you repair or replace your AC or furnace?

  Repair usually makes sense if the system is fairly young and the fix is small. Replacement is worth a look when an AC or heat pump is more than 10…

• What size AC or furnace does my house need?

  The right size comes from a Manual J load calculation, which measures how much heat your home gains in summer and loses in winter based on its…

Maintenance, rebates and permits

• Is a furnace or AC tune-up worth it?

  For most homes, yes. ENERGY STAR recommends a yearly tune-up because clean, properly adjusted equipment runs more efficiently and comfortably, and…

Indoor air quality

• How often should I change my furnace filter?

  Check a standard 1-inch furnace filter every month and replace it at least every 3 months. With pets, allergies or heavy winter and summer use, plan…

• What humidity should my house be in winter?

  Most homes do well around 30 to 40% relative humidity when it's 20 to 40°F outside, and closer to 25 to 30% when it drops below 10°F. EPA's general…

Safety and emergencies

• What to do when your carbon monoxide alarm goes off

  If your carbon monoxide alarm is sounding, get everyone (and pets) out of the house right away, then call 911 from outside. Don't try to find the…