Furnace Not Turning On: What to Check Before You Call in Eau Claire

Furnace Not Turning On: Safety Checks First

A furnace not turning on in the middle of an Eau Claire winter often traces back to something you can check in minutes, such as a thermostat setting, a tripped breaker, a clogged filter or a snow-covered vent. Work through the checks below in order. If they don’t fix it, our directory of HVAC contractors in Eau Claire is a place to start. One furnace manufacturer’s troubleshooting guide notes that technicians sometimes arrive to find the system was simply turned off, so the basics are worth a few minutes.

Rule out the two emergencies before you touch anything:

• If you smell gas: don’t operate electrical switches and don’t try to relight anything. Get everyone out, move a safe distance away and call 911 from a safe place. Then call Xcel Energy at 800-895-2999 if Xcel is your gas utility.
• If a CO alarm sounds: get everyone outside and call 911 or the fire department. Wisconsin DHS says not to go back in until the fire department has inspected and declared it safe. Our guide to carbon monoxide detector beeping explains what each alarm sound means.

A furnace owner’s manual explains that when one or more safety devices activate, furnace operation stops. A furnace that will not start is often protecting itself, so never try to get around that. The manufacturer’s guide says not to attempt repairs involving gas, oil, electrical components or internal furnace components unless you are qualified.

Furnace Not Turning On: 8 Checks in Order

Is the thermostat actually calling for heat?

The thermostat needs power, Heat mode and a setpoint above the current room temperature. Replace the batteries if it runs on them, and set the fan switch to On or Auto. If the fan doesn’t start, the manufacturer’s guide says the issue may be the furnace controls, the thermostat or the power supply.

Is the power switch or breaker off?

The furnace power switch must be On and its circuit breaker must not be tripped. The owner’s manual’s reminder list also says to replace blown fuses or reset circuit breakers.

When did you last change the filter?

Check the filter monthly, because a clogged one restricts airflow and can shut the system down. The manufacturer’s guide says many 1-inch filters last 30 to 90 days and thicker 4-inch media filters may last 6 to 12 months. ENERGY STAR says to inspect, clean or change filters once a month.

Are the supply and return vents open?

Supply and return vents should be open and unobstructed. Blocked vents can also contribute to short cycling.

Is the front panel seated?

Make sure the furnace front panel is seated, because a loose one can trigger a safety switch. Check it from the outside only, and do not open the furnace.

Is the gas valve open?

The handle on the gas valve near the furnace should sit parallel to the gas line. The owner’s manual also says to confirm that gas is on at the meter and that the manual main shut-off valve is open. If you smell gas at any point, stop and leave.

Is there fuel in the tank?

Check your propane or oil level if the home doesn’t use natural gas. An empty oil tank can shut the furnace down and may need professional service or a reset of the primary control.

What if the pilot light is out?

Relight a pilot on an older furnace only by following the owner’s manual. After a natural gas outage, do not relight appliances yourself: Xcel Energy says it will check the meter, lines and appliances and relight them free of charge, if Xcel is your gas utility.

Furnace Not Turning On After Snow or Ice

Are the outdoor vent pipes buried in snow?

Check the plastic intake and exhaust pipes outside after any heavy snow, ice or frozen fog, because the furnace owner’s manual says they may become restricted. Remove any snow or ice blocking them.

Xcel Energy gives three more rules for winter storms:

• Gently brush snow or ice from the gas meter, its piping and appliance vents.
• Keep snow blowers away from the meter.
• Watch for roof snow, which can fall and bury meters and vents.

Xcel says snow and ice around a meter can interfere with gas flow, and that a frozen meter can disrupt heating. Clear vents also matter for safety, since blocked exhaust vents can lead to CO buildup. For ice on the meter or a blocked regulator vent, Xcel’s number is 800-895-2999.

Furnace Not Turning On or Blowing Cold Air

Why is my furnace blowing cold air?

Air that isn’t hot enough usually calls for a look at the filter and vents first. The manufacturer’s guide says to replace a filter that looks gray or has a visible layer of dust, and to confirm the vents are open. If it continues, call a professional.

Why does my furnace turn on and off?

A furnace that turns on and off frequently (short cycling) may have an airflow or thermostat problem. A thermostat near a heat source, or a faulty one, can misread the room. A dirty filter can make the heat exchanger overheat and trigger a safety shutoff. Blocked vents contribute too. If replacing the filter and clearing the vents doesn’t help, call a technician to look at airflow, sizing and controls.

Why won’t my furnace ignite?

A dirty flame sensor or a failed ignitor is a common cause, and both are technician jobs. The manufacturer’s guide names the flame sensor as a reason a heater can suddenly stop, and lists the ignitor among the parts that typically fail first. Leave both alone, since they sit inside the furnace.

Furnace Not Turning On: When to Call a Technician

Call a qualified HVAC professional if the checks above don’t fix it. Our directory lists HVAC contractors in Eau Claire.

What sounds and smells mean stop?

Repeated shutdowns, burning odors, error codes and unusual noises all mean it’s time for professional service. A bang or boom at startup suggests a clogged burner delaying ignition, which is a professional job. The owner’s manual also says to shut down and call for inspection if you notice:

• Repeated new or unfamiliar sounds, or unusual odors
• Unusual condensate on windows
• Burnt components
• Dirt or rust on the vent pipe
• Headache, nausea, fatigue or dizziness at home that eases when you leave, which can point to CO

Do not use the furnace if any part has been underwater.

What should I tell the technician?

Give the make, model, serial number and symptoms. Record the model and serial number from the furnace nameplate, note any noises, uneven heating or frequent cycling, and clear the area around the furnace before the visit, as Angi suggests.

Furnace Not Turning On: National Repair Costs

How much does a furnace repair cost?

Angi’s 2026 national data puts the average furnace repair at $318, and most homeowners pay $133 to $505. There are no published Eau Claire prices, so treat these as national figures and ask for a written estimate.

Repair	National cost (Angi, 2026)
Flame sensor replacement	$150 to $250
Thermostat repair	$100 to $300
Circuit board	$200 to $600
Gas valve	$200 to $600
Draft inducer motor	$200 to $1,500

Angi puts labor at $50 to $150 an hour nationally, and small repairs are often billed at a $100 to $200 minimum. Emergency pros charge $150 to $215 an hour, and emergency repairs can cost up to twice as much. If the repair bill makes you wonder whether to keep the furnace, see our guide to furnace replacement cost.

Furnace Not Turning On in a Cold Snap: Protecting the House

Pipes are the next risk once the heat is off. Eau Claire’s January average low is 5.8°F, and the airport averages about 28 nights a year at or below 0°F (NOAA 1991-2020 normals).

How do I keep pipes from freezing while I wait?

Open kitchen and bathroom cabinet doors and let cold water drip from a faucet served by exposed pipes, as the Red Cross advises. It also says to keep garage doors closed. Our guide on keeping pipes from freezing has more detail.

If you must leave the house unattended for an extended period with no heat, the furnace owner’s manual says to shut off the water supply and drain the pipes.

What should I avoid using for heat?

Never run a gas or propane heater or a grill indoors or in the garage. Wisconsin DHS also says never to run a generator within 20 feet of your house, so keep it at least that far away.

Furnace Not Turning On and No Money for Repairs: Local Help

Who helps with no heat in Eau Claire County?

Western Dairyland, at 715-836-7511, handles no-heat calls for eligible households in Eau Claire, Clark and Trempealeau counties. It runs the Home Energy Plus HVAC program for homes whose primary heating system no longer heats, is inoperable or has become unsafe. The program can pay for repairs and, in some situations, replacement of a non-operating system. Staff are on call after hours, weekends and holidays. The statewide line is 1-866-432-8947 if you are without heat.

Who qualifies, and how fast do they respond?

Household income must be at or below 60% of the state median income. State manuals say services are discretionary, so even an eligible household may not receive them, and services never result in a lien or a charge to the household. During the heating season, October 1 to May 15, the local agency must respond within 48 hours, or 18 hours for urgent safety concerns.

Furnace Not Turning On Less Often: The Yearly Check-Up

What does a fall check-up cover?

A contractor’s check-up covers the condensate drain, controls and starting cycle, gas connections, gas pressure, burner combustion and heat exchanger, according to ENERGY STAR. It recommends scheduling in the fall, since contractors get busy once winter comes. Wisconsin DHS also says to have your furnace inspected each year by a professional.