Get the furnace ready for winter
Book the fall tune-up, check the filter every month, and seal the ducts that run through cold spaces.
Why it matters
Nearly half of the energy a home uses goes to heating and cooling, ENERGY STAR says. A furnace that runs every day from November on is worth an hour of attention in October.
The tune-up
ENERGY STAR's maintenance checklist says to have the heating system checked in the fall. A contractor's heating check covers what you should not open yourself: the gas or oil connections, the gas pressure, the burner and the heat exchanger. A dirty burner or a cracked heat exchanger can make the equipment run less safely, which is why the CO alarms belong on the same list.
The filter
The one part you can do yourself. Check the filter every month, especially in winter. If it looks dirty after a month, change it, and change it at least every three months either way. A dirty filter slows the air and makes the system work harder.
The ducts
Ducts that run through the attic, a crawlspace, an unheated basement or the garage lose heat on the way. ENERGY STAR says sealing and insulating ducts can improve a system's efficiency by as much as 20 percent. Seal the seams and joints with duct mastic or foil tape (not cloth duct tape), then wrap them in insulation.
The thermostat
Keep the heat at 55 degrees or higher, even at night and even when nobody is home, so the pipes stay safe. ENERGY STAR says homes with high heating bills, or that sit empty much of the day, can save about $100 a year with a certified smart thermostat.
The steps for furnace and filters
- Book the furnace tune-upENERGY STAR says to have the heating system checked in the fall: the gas or oil connections, the burner and the heat exchanger, which a contractor can see and you cannot.
- Check the furnace filterCheck it every month in winter. If it looks dirty after a month, change it, and change it at least every three months either way.
- Seal the ducts in unheated spacesStart with ducts in the attic, crawlspace, unheated basement or garage. Use duct mastic or foil tape on the seams, then wrap the ducts in insulation.
- Keep the heat at 55 degrees or higherEven at night, and even when nobody is home. Illinois Extension sets the floor at 55.
- Set the thermostat to 55 before you goNo lower. A smart thermostat lets you watch it, and change it, from wherever you are.
Sources
- ENERGY STAR: Heat and cool efficiently energystar.gov
- ENERGY STAR: Maintain your equipment, a checklist energystar.gov
- University of Illinois Extension: Cold weather, frozen pipes? Extension gives you all you need to know extension.illinois.edu
Drafted on October 26, 2026 with a language model from the pages listed above, each opened that day, and sampled by the editor after publication. Every figure is computed by the same code the tools run, and a test fails the build if one stops matching.
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