Furnace Installation in Fond du Lac, WI
A new furnace here will run from September through May every year. Tell us about the house, and a licensed contractor who covers Fond du Lac County will get in touch.
Tell us about the job
It takes about a minute.
Nine months of heat, and nights that drop to 13 degrees
Fond du Lac County homes need the furnace running from September through May. That is nine months of the year. On winter nights averaging 13°F, a furnace has to bring the house up to temperature and hold it there for hours, night after night, with little break between one heating season and the next.
A furnace installed here has to be sized for that, not for a mild cold snap. Any non-weatherized gas furnace built today has to reach at least 80 percent AFUE, so more of every dollar spent on gas turns into heat rather than exhaust. Wisconsin also saw 18 percent of households lose power for a day or more in 2024, and the county has logged 15 winter storms and 59 damaging wind events over the past ten years. Worth asking how a new furnace handles a power outage before the install is done, not after the next storm.
- 9 months
- September through May, your furnace is on duty
- 13°F
- the average winter night it heats against
- 66%
- 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 $100 a year to run in Fond du Lac County compared with a gas furnace.
Estimates for a typical Fond du Lac County home, from EIA household energy data, Wisconsin fuel prices and NOAA climate normals. Your home will differ.
Wisconsin requires contractors to register with the state.
The registration puts the business on file with the Department of Safety and Professional Services. Nobody tested this contractor on furnace installation to get that number, and the state does not track complaints or revoke it for bad work. Wisconsin also does not let Fond du Lac County or its cities set their own HVAC license on top of this, so the registration is the only state-level record that exists for this job.
What actually backs up a furnace installation here is the permit. Most cities and counties in Wisconsin require a permit before a furnace goes in and an inspection once it's done, and that inspection is what catches a bad gas connection, a vent that's not right, or a flue that was rushed. With most homes in Fond du Lac County heating with gas, that inspection is doing the job people usually assume a license does.
Sources: Wisconsin Legislative Reference Bureau · Wisconsin Department of Safety and Professional Services
- What size furnace does my house need?
- The right size comes from a load calculation, not the size of the furnace you have now. A contractor measures your square footage, your insulation, your windows, and your ceiling height, then runs those numbers to find out how much heat your house actually loses on a cold night. Too big and the furnace short cycles, heating the air fast but never running long enough to warm the house evenly. Too small and it runs constantly and still can't keep up. With winter nights here averaging 13°F, getting this number right matters more than it would somewhere milder.
- How do I know it's time to replace my furnace?
- Age is the first thing to check. A furnace running well past its expected age is working harder to do the same job it used to do easily. Watch for rising gas bills with no other explanation, rooms that heat unevenly, short cycling, or a burner flame that looks yellow instead of blue. A contractor can tell you whether a repair makes sense or whether replacing it is the better move, and that decision matters more here since homes need heat nine months of the year and a failing furnace has little time to rest between seasons.
- Is a high-efficiency furnace worth it?
- For a house that needs heat from September through May, a high-efficiency furnace has a lot more months to earn back the difference than one running only a few months a year elsewhere. Every furnace made since November 2015 has to hit at least 80 percent AFUE, and high-efficiency models go higher than that by pulling more heat out of the exhaust before it leaves the house. A contractor can look at your current furnace's rating and your house's heating load to tell you what the jump in efficiency would actually mean for your situation.