Furnace Installation in Marion, IL
A new furnace here will run from October through April every year. Tell us about the house, and a licensed contractor who covers Williamson County will get in touch.
Tell us about the job
It takes about a minute.
Marion asks a furnace to work seven months a year
From October through April your furnace is the thing standing between your house and a winter night that averages 27°F. That is seven months of regular use, not just a few cold snaps.
Most homes in Marion heat with electricity, so a bad ice storm that knocks out power can take the furnace with it. Williamson County has seen 14 winter storms and 88 damaging wind events over the past ten years, and in 2024, 16% of Illinois households lost power for 24 hours or more. Any furnace installed today also has to meet the federal minimum of 80.0 percent AFUE, so you know it is built to actually use the fuel it burns.
- 7 months
- October through April, your furnace is on duty
- 27°F
- the average winter night it heats against
- 80% AFUE
- the federal minimum any new unit must meet
NOAA nClimDiv, 1991–2020 normals
In Illinois, HVAC licensing for homes is left to the cities and towns.
Williamson County sets its own rule on who can do this work, since Illinois leaves HVAC licensing to the cities and towns rather than handling it at the state level. That means there's no state license to check and no statewide test a contractor had to pass. Whatever requirement exists here comes from the county, not from Springfield.
For a furnace installation, the protection you have is the permit process. In most places, swapping in a new furnace needs a permit from the local building office, and the finished work gets inspected before it's signed off. That inspection is what catches a bad gas connection or a venting mistake, not a license number. The permit and the inspection are the record that this job was done and checked, in a state where no license does that job for you.
Source: Illinois General Assembly
- What size furnace does my house need?
- It depends on your square footage, your insulation, your windows, and your ceiling height, so no online chart will get it exactly right. A contractor works this out with a load calculation that looks at your actual house, not just its size on paper. Going too big wastes fuel and cycles the furnace on and off more than it should, while too small leaves rooms cold on the coldest nights. With winter lows here averaging 27°F and heat needed October through April, getting this number right matters more than it would somewhere milder.
- How do I know it's time to replace my furnace?
- An aging furnace that needs more repairs each year is usually the first sign, especially once a repair bill starts to rival what a new furnace would cost. Watch for rooms that heat unevenly, a furnace that runs longer than it used to, or a rise in your gas bill with no other explanation. If a contractor has told you the heat exchanger is cracked, that is not a repair, that is a replacement, since a cracked heat exchanger can leak carbon monoxide into your home. With heat needed here from October through April, a furnace that cannot keep up is not something to leave for next season.
- Is a high-efficiency furnace worth it?
- It depends on what you have now and how long you plan to stay in the house. Furnaces built since November 2015 already have to reach 80 percent AFUE at minimum, so if yours is older than that, almost any new furnace will burn less gas than what you have. A high-efficiency model pulls more heat out of the same amount of fuel and vents through PVC pipe instead of a metal flue. With heat running seven months a year here, that difference adds up faster than it would in a milder climate, but a contractor can walk you through the actual models and what each one would mean for your house.