Your furnace is running, the thermostat says heat, and the air coming out of the vents is cold. Most of the time it’s one of eight things you can check yourself in about ten minutes. This guide covers those checks, what furnace repair costs if you need one, and how to tell a small fix from a replacement conversation.
Furnace Repair in the Quad Cities
Doug’s Heating & Air Conditioning has handled heating repair across the Quad Cities for decades, covering Moline, Davenport, Rock Island, Bettendorf, East Moline, Silvis, Milan, Coal Valley and the surrounding towns with 24/7/365 emergency service. Our union technicians work out of a fleet of more than 15 service and installation vehicles, and emergency service runs 365 days a year, nights and holidays included. We work on every major brand, including YORK® and Mitsubishi equipment. When your furnace isn’t producing heat, we find the actual cause, explain it in plain language, and give you the repair price before any work starts.
Why Is My Furnace Not Blowing Hot Air? 8 Things to Check First
A furnace that runs but blows cold air is usually doing one of two things: the blower is running while the burners aren’t lighting, or a safety switch has shut the burners down and left the fan on. Both have simple causes worth ruling out before you book a repair. A thermostat set to fan-On instead of Auto will push room-temperature air all day and feel exactly like a broken furnace. A clogged filter can overheat the furnace and trip a limit switch within a few minutes of startup. The eight checks below are safe for a homeowner, take about ten minutes, and if you do end up calling us, they help our technician get to the cause faster.
Before anything else: if you smell gas, see scorch marks around the furnace, or your carbon monoxide alarm is sounding, leave the house immediately. Call 911 and MidAmerican Energy at 800-595-5325 from a safe distance. Do not go back inside to keep troubleshooting.
1. Start with your thermostat
Many no-heat calls end here. Set the mode to Heat, set the temperature a few degrees above the current room temperature, and set the fan to Auto rather than On. Replace the batteries if it has them, and check that a setback schedule isn’t holding the temperature down. A blank or flickering display points to a thermostat or low-voltage fault that needs a technician.
2. Confirm the system actually has power
A gas furnace will not run without electricity. Check the switch on or near the furnace that looks like a light switch, because these get flipped by accident. Then check your panel for a breaker labeled furnace, air handler, or HVAC, and reset it once. Make sure the furnace door panel is seated properly too, since many units cut power when it’s off. If the breaker trips a second time, stop. Repeated trips point to an electrical or motor fault, and cycling the breaker can make the damage worse.
3. Check your filter and return air
A clogged filter is one of the most common causes of a furnace that starts, runs briefly, then blows cold. Pull the filter from the return grille or the slot near the furnace, and if it’s gray or packed with dust, replace it with the arrow pointing toward the furnace. Clear furniture and rugs off the return grilles.
A starved furnace overheats, a safety limit shuts the burners down, and the blower keeps running, which is why you feel cold air. After a fresh filter and a 30-minute cool-down it may restart on its own.
4. Make sure your supply vents are open
In the older housing around Moline and Rock Island, vents get closed off and forgotten. Open every supply register fully and move rugs, furniture, and drapes clear. Note which rooms run coldest, since that’s useful for your technician. Closing vents to save money usually backfires, because it raises static pressure in the ductwork and makes the whole system work harder.
5. For gas furnaces, check the simple fuel problems
If the blower runs but the air stays cold, the burners may not be lighting. Confirm the gas shutoff valve at the furnace is parallel with the pipe, which means open. Then try another gas appliance like your range. If nothing gas-fired works, the problem is your gas service rather than your furnace, and MidAmerican Energy is the call. On an older standing-pilot furnace, look through the viewing window to see whether the pilot is lit. Leave the burner assembly, gas valve, and igniter alone. Those are licensed-technician jobs.
6. For heat pumps, check the outdoor unit
Plenty of Quad Cities homes heat with a heat pump or ductless mini split, often with a furnace as backup. Light frost on the outdoor coil is normal, and the system should periodically run a defrost cycle where the fan stops and steam comes off the unit. Clear snow from the base, keep the top and sides open, and check the disconnect switch nearby. If the unit is a solid block of ice, grinding, or refusing to defrost, shut it off and call us.
7. Look for an error code
Most furnaces built in the last 25 years flash a diagnostic code when they fault. Look for a small viewing window on the cabinet, watch for a blinking LED, and count the blinks or write down whatever the display shows. You don’t need to decode it. Telling our technician what you saw shortens the diagnosis.
8. Know when to stop and call
Stop troubleshooting and call Doug’s if you notice burning, electrical, or gas odors, a breaker that trips more than once, banging or screeching from the blower, short cycling where the furnace quits after a minute and repeats, a sounding carbon monoxide alarm, or visible soot, rust, or cracking around the heat exchanger.
How Much Does Furnace Repair Cost in the Quad Cities?
Most furnace repairs cost $125 to $480, according to HomeGuide’s 2026 cost data, with a national average around $300. The two most common failures are near the bottom of that range: a dirty or failed flame sensor, the usual reason a modern furnace lights and then shuts off after a few seconds, and a cracked hot surface igniter. The expensive repairs are the motors and the heat exchanger, and those are the ones where replacing the furnace can make more sense than fixing it. The table below shows national ranges from two cost guides. They’re estimates, not Doug’s prices, and a part on an accessible furnace in a dry basement is a different job from the same part in a tight crawlspace. Doug’s diagnoses the fault first and gives you a price before any work starts.
| Repair | HomeGuide (2026) | Angi (2026) |
|---|---|---|
| Flame sensor | $80 to $250 | $150 to $250 |
| Hot surface igniter | $100 to $250 | $150 to $500 |
| Thermocouple (older standing-pilot furnace) | $100 to $300 | Not listed |
| Limit switch | $100 to $375 | Not listed |
| Gas valve | $200 to $800 | $200 to $600 |
| Control board | $300 to $650 | $200 to $600 |
| Blower motor | $300 to $900 | $150 to $2,000 |
| Draft inducer motor | $400 to $1,100 | $200 to $1,500 |
| Heat exchanger replacement | $1,000 to $3,000 | $500 to $1,500 |
Doug’s also takes $25 off HVAC repairs as an online special. Check our current specials for what’s running this month.
HomeGuide notes that most technicians replace a failed heat exchanger rather than repair it, because a crack can leak carbon monoxide. On a furnace past about 12 years old, that repair usually leads to a replacement conversation.
What Does a No-Heat Call Cost After Hours?
After-hours, weekend, and holiday HVAC service typically runs $140 to $210 per hour, compared with $75 to $150 per hour during normal hours, according to HomeGuide. Angi puts a full emergency furnace repair at about $300 to $1,200. Doug’s Gold Maintenance Plan members pay no after-hours fees, which is worth knowing if you’re weighing a plan before winter. We answer the phone around the clock either way, at 563.326.1223 in Iowa and 309.764.2500 in Illinois.
Repair or Replace? The $5,000 Rule
The $5,000 rule is a quick way to decide: multiply your furnace’s age in years by the estimated repair cost, and a result over $5,000 leans toward replacement. A 20-year-old furnace with a $400 repair comes to $8,000, which says replace. An 8-year-old furnace with a $300 igniter comes to $2,400, which is an easy repair. When the math lands near the line, local conditions help decide it. The 99% winter design temperature for Rock Island County, Illinois and Scott County, Iowa is -2°F (RESNET/ICC Appendix A, ASHRAE 2017 Handbook of Fundamentals). That’s the temperature your heating system has to hold the house against, and it changes two things:
- A marginal furnace carries more risk here. A furnace that fails during a hard freeze can mean frozen and burst pipes, which cost far more than the furnace. A 15-year-old unit facing a $350 repair lands at $5,250, right on the line, and in this climate we’d lean toward furnace replacement.
- Most homes here still need a furnace. Cold-climate heat pumps from makers like Mitsubishi are rated to hold full capacity down to 5°F, which is above the local design temperature. That’s why most Quad Cities heat pump installs keep a furnace or a dual-fuel setup for the coldest stretches.
When the math is close, we’ll walk you through both options with real numbers and let you decide. Our furnace replacement cost guide covers what a new furnace runs here. Doug’s old-furnace buyback, currently $500 toward a new energy-efficient model, can change a borderline call. It can’t be combined with other Doug’s discounts.
Will My Furnace Work During a Power Outage?
No. A natural gas furnace will not produce heat without electricity, because the blower motor, the hot surface igniter, the draft inducer, and the control board all run on household power. The gas keeps flowing during an outage, and the furnace still won’t light. Winter ice storms do take down lines in the Quad Cities, and in a long outage during a cold snap, pipes in exterior walls and crawlspaces can start freezing within hours. If you’ve lost heat because you’ve lost power, the fix is a standby generator rather than a furnace repair. We cover the cost in What Does a Whole-House Generator Cost in the Quad Cities?
When Is a No-Heat Problem a Carbon Monoxide Emergency?
A furnace problem becomes a carbon monoxide emergency when combustion gases stop venting properly. Carbon monoxide is odorless and colorless, and the CDC lists gas- and oil-burning furnaces among the household items that produce it. Each year, according to the CDC, more than 400 Americans die from unintentional carbon monoxide poisoning not linked to fires, more than 100,000 visit an emergency department, and more than 14,000 are hospitalized. The CDC says symptoms are “often described as flu-like”: headache, dizziness, weakness, nausea, chest pain, and confusion. People who are asleep can die from carbon monoxide poisoning before they have symptoms, which is why alarms matter.
What to do:
- Alarm sounding, or flu-like symptoms that improve when you go outside: get everyone out and call 911.
- Smell of gas: follow the steps at the top of this post.
- Replace carbon monoxide alarms every five years, or on the manufacturer’s schedule, and install them near every sleeping area.
- Cracked heat exchanger: this is the furnace failure that produces carbon monoxide. Doug’s technicians check the heat exchanger and venting on a no-heat call.
MidAmerican Energy supplies gas on both sides of the river, so it’s the same emergency number, 800-595-5325, whether you’re in Illinois or Iowa.
MidAmerican Instant Discounts on a New Furnace
If you decide to replace, MidAmerican Energy’s Instant Discounts program takes money off a qualifying natural gas furnace at the point of purchase, at $2.40 per MBtuh of input capacity. On an 80,000 BTU furnace that’s about $192, and on a 100,000 BTU unit about $240. There’s no rebate form, because the discount comes off the price. The equipment has to be purchased, installed and operating in 2026, the discount is only available through providers that participate in the program, and it can’t be combined with other MidAmerican rebates. MidAmerican suggests asking your contractor whether they participate, and the full terms are on MidAmerican’s discounts and rebates page.
There is no federal tax credit on a 2026 furnace. The 25C credit ended for equipment placed in service after December 31, 2025.
Prevent the Next No-Heat Emergency
The least expensive furnace repair is the one caught at a scheduled tune-up. A cracked igniter found in October is a weekday repair. The same part failing in January can mean an after-hours call on the coldest night of the month. Doug’s maintenance plans include two visits a year, one for heating and one for cooling:
| Plan | Price | What it includes |
|---|---|---|
| Silver Maintenance Plan | $250 per year | Heating system cleaning and inspection, cooling system cleaning and inspection |
| Gold Maintenance Plan | $340 per year | Everything in Silver, plus 10% off parts and labor for the year, no after-hours fees, and priority service |
A tune-up also gives a technician the chance to spot heat exchanger cracks and venting problems before they turn into safety calls. New plans are currently 10% off.
Frequently Asked Questions
What is the average cost to repair a furnace?
Most furnace repairs cost $125 to $480, with a national average around $300, according to HomeGuide’s 2026 data. The main exception is the heat exchanger, at $1,000 to $3,000, which is also the only common furnace repair that’s a safety issue rather than a comfort one.
What is the $5,000 rule for HVAC?
Multiply the equipment’s age in years by the repair cost. A result over $5,000 points toward replacement. It’s a starting point rather than a verdict, and in a climate with a -2°F design temperature, we’d lean toward replacement when the number is close.
Should a 25-year-old furnace be replaced?
In most cases, yes. HomeGuide notes that replacement is usually the better choice for a furnace that needs frequent repairs or is more than 20 years old. At 25, parts get harder to find, efficiency is well below a current model, and heat exchanger cracks become more likely.
How long should a furnace last in the Quad Cities?
HomeGuide puts furnace life at 15 to 30 years, depending on the brand, installation, usage and maintenance. A Quad Cities furnace runs more hours each winter than one in a mild climate, so annual maintenance does a lot to decide which end of that range you land on.
What is the most expensive part to fix on a furnace?
The heat exchanger, at roughly $1,000 to $3,000 installed according to HomeGuide. It’s also the most safety-critical part, because a cracked heat exchanger can leak carbon monoxide into your home. On an older furnace, the repair cost usually points toward replacement.
Why is my furnace blowing cold air instead of hot air?
The most common cause is that the burners aren’t lighting while the blower keeps running, usually from a dirty flame sensor, a failed igniter, or a safety limit shutting the burners down because of a clogged filter. It can also be as simple as the thermostat fan being set to On instead of Auto, which runs the blower continuously and moves unheated air. Check the filter and the fan setting first.
Ready for Heat? Doug’s Is Here 24/7
If you’ve worked through the checks and still have no heat, call us. Doug’s Heating & Air Conditioning provides 24/7/365 furnace repair across Moline, Davenport, Rock Island, Bettendorf, and the surrounding Quad Cities. Reach us in Iowa at 563.326.1223 or in Illinois at 309.764.2500, or request service online.
We’ll tell you what’s wrong, what it costs, and whether repairing it makes sense. Financing through Synchrony is available if the answer turns out to be a new system.
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