Furnace Installation in Ottawa, IL
A new furnace here will run from October through May every year. Tell us about the house, and a licensed contractor who covers LaSalle County will get in touch.
Tell us about the job
It takes about a minute.
Eight months of heat, and winter nights near 19 degrees
Furnaces around LaSalle County work from October through May. That is eight months a year of regular runtime, in a place where winter nights average 19°F. A furnace here needs to hold up to that stretch, not just get through a cold snap.
Most homes in the area heat with gas, and any new gas furnace has to meet the federal minimum of 80 percent AFUE. Power is worth planning around too. Across Illinois, 16 percent of households lost power for 24 hours or more in 2024, and this area has logged 19 winter storms and 124 damaging wind events over the past ten years. A furnace installed here should be sized and set up for the winters this place actually has.
- 8 months
- October through May, your furnace is on duty
- 19°F
- the average winter night it heats against
- 76%
- of homes here heat with gas, so most furnaces here burn gas
- 80% AFUE
- the federal minimum any new unit must meet
NOAA nClimDiv, 1991–2020 normals
A high-efficiency gas furnace would save about $130 a year to run in LaSalle County compared with a gas furnace.
Estimates for a typical LaSalle County home, from EIA household energy data, Illinois fuel prices and NOAA climate normals. Your home will differ.
In Illinois, HVAC licensing for homes is left to the cities and towns.
That means whether a contractor needs a local license to install your furnace depends on which city or town in LaSalle County the house sits in. Some places keep their own list of licensed contractors, others register businesses without testing anyone, and some have no rule at all. There is no statewide test or license behind the person doing this work, only whatever the local office requires.
What covers you here is the permit process. In most cities and counties, replacing a furnace needs a permit from the local building office and an inspection once the work is done, and that inspection is what checks the gas connection, which is the part of this job that can hurt someone if it is done wrong. With most homes in LaSalle County heating with gas, that inspection is doing the job a license would do somewhere else.
Source: Illinois General Assembly
- What size furnace does my house need?
- The right size depends on your home's square footage, how well it's insulated, your window count, and your ceiling height, so a contractor needs to walk through and run a load calculation to get it right. Guessing based on your old furnace's size is not a good starting point, especially if that furnace was installed decades ago under different building codes. Too big and it short cycles, wearing out parts fast and leaving rooms uneven. Too small and it runs constantly and still can't keep up on the coldest nights. Since homes here need heat from October through May, getting this number right matters more than in places with a short winter.
- How do I know it's time to replace my furnace?
- If your furnace is having trouble keeping the house warm through nights that average 19°F, is cycling on and off more than it used to, or needs a repair call more than once a season, it's time to start looking at replacement. An older furnace working harder than it used to, even without a full breakdown, is also a sign. Rising gas bills without a clear reason, uneven heat between rooms, and a burner flame that looks yellow instead of blue are also worth having a contractor check out.
- Is a high-efficiency furnace worth it?
- It depends on how long you plan to stay in the house and what your current furnace costs to run, and a contractor can walk you through the actual math for your situation. What's true everywhere is that any furnace made since November 2015 is required to hit at least 80 percent AFUE, so even a standard model today isn't wasting nearly as much fuel as an old one. A high-efficiency furnace pulls more heat out of the same amount of gas than one built to that minimum, which matters here since 76.1 percent of homes heat with gas and the furnace runs for 8 months of the year.