Every time your thermostat calls for heat, the furnace works through a fixed checklist. The inducer motor starts and proves draft by closing a pressure switch, the hot surface igniter heats up, the gas valve opens, the burners light, and the flame sensor confirms there is fire. Only after all of that does the blower begin sending warm air into the house. Finding the step that fails is most of the job. Around Janesville, WI, the usual failure points are a flame sensor fouled with oxide, an igniter cracked by years of heating and cooling, a pressure switch that stays open because of a weak inducer or a clogged condensate trap on a high-efficiency unit, and control boards with burned relays. Any one of them halts the startup, and from the hallway they all look alike.
Rather than guess, Janesville HVAC tests the sequence stage by stage. We read igniter resistance, measure flame signal in microamps, check that the pressure switch responds to real inducer draft, confirm voltage at the gas valve, and test the blower and its capacitor. Because this is a fuel-burning appliance, the safety basics come with every visit: the heat exchanger gets inspected, gas connections get leak-tested, and draft gets verified. You cannot tell a furnace problem from a furnace hazard by looking at the thermostat. Before we leave, temperature rise is measured against the data plate so the fire and the airflow are balanced as the manufacturer intended.
Janesville HVAC services natural gas, propane, and electric furnaces from all major brands, from standard 80 percent units to condensing high-efficiency models with their traps, drain lines, and dual pressure switches. Our trucks carry the parts that really fail, such as igniters, flame sensors, pressure switches, capacitors, inducer assemblies, and blower motors, so a typical no-heat call ends with the house warming up. Call (920) 516-9404 for furnace repair anywhere in Janesville, and we can have someone out today.
For air conditioning breakdowns, see AC Repair in Janesville.
How Much Does Furnace Repair Cost in Janesville?
For most Janesville homes, a furnace repair runs $150 to $600. Cleaning a flame sensor is a small job; replacing a blower motor or control board is a bigger one. Every furnace repair starts with a real diagnosis and a clear price.
| Repair | Typical cost | What it usually means |
|---|---|---|
| Flame sensor cleaning or replacementFurnace lights, then shuts off within seconds | $80–$250 | Burners light but cut out almost immediately |
| Hot surface igniter replacementNo ignition; one of the most common winter failures | $150–$400 | Furnace clicks and tries to start but never lights |
| Draft inducer motorLoud humming or grinding at startup, then lockout | $400–$1,000 | Startup fan fails, furnace won't fire |
| Blower motorBurners run but little or no air comes out of the vents | $400–$1,500 | No airflow, or the blower runs nonstop |
| Control boardFurnace won't respond to the thermostat | $300–$700 | Furnace won't respond to the thermostat |
| Gas valve replacementValve fails to open, so the furnace never lights | $250–$700 | Valve fails to open, so the furnace never lights |
Ranges are typical for these repairs; you get an exact quote before any work starts.
What Moves the Cost Up or Down
- Furnace age and type, because 90%+ efficiency models have more specialized parts
- A cracked heat exchanger, which is a safety issue and usually points to replacement
- Same-day or after-hours service versus a planned visit
- Access to the furnace in attics, closets, or crawlspaces
If your furnace is past 15 to 20 years old or the repair is a major one, we'll give you repair and replacement prices side by side. Call (920) 516-9404 to get your price.
When to Call for Furnace Repair in Janesville
Recognizing the warning signs early can save you time, money, and prevent significant damage to your property. Keep an eye out for the following clues that it's time to bring in an expert:
- Yellow, wavering burner flames where they should be sharp blue
- The igniter glows and clicks, yet no flame ever appears
- Burners light, run a few seconds, then shut down repeatedly
- Air moving through the vents that never gets warm
- Short cycling every few minutes without reaching the setpoint
- Booming or banging at light-off from delayed ignition
- Rust streaks, soot, or water around the cabinet or flue
- Squealing or grinding from the blower compartment
Act Before It Gets Worse
Most HVAC failures start small, a weak capacitor, a squealing blower, a system that runs a little longer each week. Call Janesville HVAC at (920) 516-9404 at the first sign of trouble.
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Call (920) 516-9404 TodayYour Furnace Repair Questions Answered
The Benefits of Professional Furnace Repair
The failure that matters most in a furnace is usually hidden. A cracked or corroded heat exchanger can let combustion gases into the airstream, and nothing about it is visible from the outside of the cabinet. Delayed ignition makes things worse, because each boom at light-off puts more stress on that metal. Add high voltage, a gas valve, and a flue to the same box, and there is little room for guesswork. Diagnosis is full of traps too. A high limit that keeps tripping could be a bad switch, or it could be doing exactly its job because a filter is clogged or the blower is dying, and swapping out a working switch only hides the real fault.
Our experienced technicians treat every symptom as a question about the whole system. Flame signal gets measured rather than assumed, so a healthy sensor is never replaced while a cracked igniter or weak gas valve skates by. Draft is verified at the pressure switch and the flue. Temperature rise is checked against the data plate, which is how airflow problems get caught before they shorten the exchanger's life. And the gas side is leak-tested with instruments, not a sniff and a shrug. The result is a furnace that has been proven safe and correct under a full cycle, and an honest report if the unit is nearing the point where replacement beats another repair.
Our Furnace Repair Process
Our systematic workflow delivers thorough, lasting results on every job. Here's a look at each step our Janesville HVAC team takes:
Startup Sequence Testing
We watch the furnace's startup sequence and measure at every stage: inducer draft, pressure switch, igniter resistance, flame signal, and gas valve operation, to find exactly where it breaks.
Combustion Safety Check
On every visit, we inspect the heat exchanger, leak-test the gas connections, and confirm the flue is drafting. No furnace repair is complete until the unit is proven safe.
Expert Repair
Most furnace repairs finish in one trip. The common failure parts, from igniters and flame sensors to pressure switches, capacitors, and motors, are stocked on the truck and ready to go.
Full Verification
The last step is a full-cycle test: temperature rise matched to the data plate, smooth ignition with no booming, and every limit switch and safety control confirmed working.
Questions About Furnace Repair?
We provide honest advice and upfront pricing on all furnace repair work.
Call (920) 516-9404 NowMaintenance Tips for Furnace Repair
Smart maintenance is almost always cheaper and easier than an early replacement. Here are our expert recommendations:
- Keep a working carbon monoxide alarm on every level of the home and check it each month
- Have the furnace checked every autumn, while a weak igniter or fouled sensor is still an easy fix
- Keep the condensate trap and drain clear on high-efficiency units to prevent lockouts
- Clear boxes, lint, and above all chlorine-based cleaners out of the furnace area
- Give the furnace room to breathe, since a crowded utility space starves the burners of air
- Pay attention when the burners light, since a boom instead of a soft whoosh calls for service
- Change the filter monthly during heating season; it is the cheapest furnace part you will ever buy
Comparing DIY and Professional Furnace Repair
Some simple checks are suitable for DIY, but most heating and cooling repairs benefit from professional tools, training, and experience. Consider the following comparison:
| Factor | DIY Attempt | Professional Service |
|---|---|---|
| Heat Exchanger | Damage hidden inside the cabinet | Checked every time we open the unit |
| Ignition Faults | New igniter installed on a hunch | Every stage measured before replacing parts |
| Gas Safety | Small leaks missed entirely | Every fitting checked with a detector |
| High-Limit Trips | A safety device jumpered out | Root cause of overheating corrected |
| Airflow Match | Blower speed left wherever it was | Temperature rise set to the data plate |
| Verification | Declared fixed after one flame | Full cycles proven clean and safe |
Talk to a Furnace Repair Expert
Every day you wait puts more strain on a struggling unit. Get Janesville HVAC on the job today.
Call (920) 516-9404 NowFurnace Repair Across the Janesville Area
Our technicians handle furnace repair throughout Janesville and the surrounding communities, with the same upfront pricing everywhere we work.