5 Most Common HVAC Repairs in Metro Detroit & Prevention
After 35 years serving Southeast Michigan homeowners, we've seen the same HVAC repairs come up year after year. Not because systems are poorly made—but because Michigan's climate puts unique stress on heating and cooling equipment. Polar vortex events that drop temperatures to -15°F in January. Humid summers that push air conditioners to their limits. Basements that flood during spring thaws. All of it takes a toll.
The good news? Most of these repairs are preventable. When homeowners in Sterling Heights, Troy, and Royal Oak call us for heating and cooling services in Metro Detroit, we're often fixing problems that could have been caught during a routine tune-up. This guide walks through the five most common HVAC repairs we handle—what causes them, what they cost, and how you can avoid them entirely.
1. Furnace Ignitor Failure
This is the number one repair call we get every November. A homeowner wakes up to a cold house, checks the thermostat, and realizes the furnace won't start. In most cases with modern gas furnaces built after 2000, the culprit is a failed hot surface ignitor.
What It Is and Why It Fails
Hot surface ignitors are ceramic or silicon nitride components that glow red-hot to ignite the gas in your furnace. They replaced standing pilot lights in most residential systems because they're more efficient and safer. But they're also fragile. The ignitor cycles on and off every time your furnace runs—sometimes 10-15 times per day during a Michigan winter. Over time, thermal stress causes micro-cracks. Eventually, the ignitor can't reach ignition temperature, and your furnace shuts down on safety lockout.
Average lifespan? Four to seven years, depending on how often your furnace cycles. If you're dealing with furnace short-cycling issues, that lifespan can drop to two or three years because of the increased stress.
Signs You Need This Repair
- Furnace won't start, even though the thermostat is calling for heat
- You hear the blower motor running, but no warm air
- Clicking or ticking sounds from the furnace cabinet
- Furnace tries to start, then shuts down after 10-15 seconds
- Error code on the control board (often a flashing LED sequence)
Prevention Strategy
There's no way to prevent ignitor wear entirely—it's a consumable part. But you can extend its life and catch failure early with annual furnace maintenance. During a fall tune-up, a qualified technician will inspect the ignitor for cracks, measure its resistance with a multimeter, and replace it if it's near end-of-life. That's far better than discovering the problem at 2 a.m. on the coldest night of the year.
Also critical: change your air filter every 60-90 days. A clogged filter restricts airflow, which causes your furnace to overheat and cycle more frequently. More cycles mean more ignitor stress.
Cost Reality
Ignitor replacement during normal business hours: $150-$400, depending on the furnace brand and ignitor type. Carrier and Lennox ignitors tend to run on the higher end. Emergency service on a Sunday night? Add $100-$200 to that. This is exactly why we recommend the Next Care Plan—our $5/month maintenance plan includes priority scheduling and a 10% discount on repairs, which more than pays for itself if you need one emergency call avoided.
2. AC Refrigerant Leaks
Refrigerant doesn't "run out" the way gasoline does. It's a closed-loop system. If your AC is low on refrigerant, there's a leak somewhere—and just adding more refrigerant without fixing the leak is a temporary band-aid that wastes money and harms the environment.
How Leaks Develop
Most refrigerant leaks happen at connection points, valve cores, or in the evaporator coil. Vibration from the compressor, corrosion from moisture, and thermal expansion/contraction cycles all contribute. In Michigan, the freeze-thaw cycle is particularly hard on outdoor condensing units. We see a lot of leaks in systems that are 10+ years old, especially if they use R-22 refrigerant (which is being phased out under EPA regulations).
Evaporator coil leaks are especially common in humid climates—and yes, Michigan summers are humid. Condensation forms on the coil, and if the drain pan isn't draining properly, that moisture sits on the coil and accelerates corrosion.
Signs You Have a Refrigerant Leak
- AC runs constantly but doesn't cool the house below 75-78°F
- Ice forming on the refrigerant lines or evaporator coil
- Hissing or bubbling sounds near the indoor or outdoor unit
- Higher-than-normal electric bills (the compressor works harder when refrigerant is low)
- Warm air blowing from vents even though the thermostat is set to cool
If you're noticing hissing or buzzing sounds from your AC, that's often an early warning sign of a refrigerant leak.
Prevention Strategy
Annual spring AC maintenance is the best defense. A technician will check refrigerant levels, inspect coils for corrosion, and test for leaks using electronic leak detectors or UV dye. Catching a small leak early—before the system loses enough refrigerant to damage the compressor—can save you thousands.
Also: keep vegetation trimmed back from your outdoor condenser unit. Overgrown bushes trap moisture and accelerate corrosion on the coil fins and refrigerant lines.
Cost Reality
Finding and repairing a refrigerant leak: $200-$1,500, depending on location and severity. If the leak is in an accessible valve or connection, it's a quick fix. If it's inside the evaporator coil in your attic or basement, you're looking at coil replacement, which can run $800-$1,500 in parts and labor. Add refrigerant recharge on top of that—R-410A costs about $50-$100 per pound, and most systems hold 6-12 pounds.
If your system uses R-22 (Freon) and has a major leak, it's often more cost-effective to replace the entire AC unit rather than pay $150+ per pound for discontinued refrigerant.
3. Blower Motor and Capacitor Problems
Your blower motor is the workhorse of your HVAC system. It runs during both heating and cooling, pushing air through your ductwork and into your home. When it fails, you get no airflow—which means no heating or cooling, even if the rest of the system is working perfectly.
What Causes Blower Motor Failure
Most blower motor problems are actually capacitor failures. The capacitor is a small cylindrical component that provides the electrical "kick" to start the motor and keep it running. Capacitors have a limited lifespan—typically 10-20 years—and Michigan's temperature swings accelerate wear. A capacitor that sits in a 140°F attic in July and a 10°F basement in January doesn't last as long as one in a climate-controlled space.
When the capacitor fails, you'll hear the motor humming but not spinning. Sometimes it'll start if you manually spin the blower wheel (don't do this—it's dangerous). Other times, the motor won't respond at all.
The motor itself can fail due to bearing wear, overheating (from a clogged filter restricting airflow), or electrical issues. Motors in systems 15+ years old are more prone to failure simply because they've logged tens of thousands of operating hours.
Signs of Blower Motor or Capacitor Problems
- No airflow from vents, even though the furnace or AC is running
- Humming or buzzing sound from the indoor unit
- Weak airflow—some rooms get air, others don't
- Intermittent operation—airflow starts and stops randomly
- Burning smell from the vents (motor overheating)
Prevention Strategy
Change your air filter regularly. A clogged filter is the number one cause of premature blower motor failure because it forces the motor to work harder to move air. In Michigan homes with pets or older ductwork, that means changing the filter every 30-60 days, not the 90 days the manufacturer suggests.
During annual maintenance, your technician will lubricate motor bearings (if applicable—some motors are sealed), test capacitor voltage, and check for unusual sounds or vibration. Catching a weak capacitor before it fails completely prevents a no-heat or no-AC emergency.
Cost Reality
Capacitor replacement: $150-$300. It's a 15-minute repair for a qualified technician, but the part itself costs $30-$80 depending on the microfarad rating and voltage. Blower motor replacement: $400-$1,200, depending on motor type (single-speed, multi-speed, or variable-speed ECM motor). Variable-speed motors cost more but are significantly more efficient—if you're replacing a motor in a 15-year-old furnace, it's worth considering a furnace upgrade instead of sinking $1,000 into an aging system.
4. Thermostat Malfunctions
Thermostats are the brain of your HVAC system, but they're often the most overlooked component. Homeowners assume that if the thermostat display is lit up, it's working correctly. Not always.
Common Thermostat Issues
Old mechanical thermostats (the round dial type) can lose calibration over time. You set it to 70°F, but the actual room temperature is 68°F or 72°F. The bimetallic coil inside the thermostat drifts, and suddenly your furnace is cycling too often or not often enough.
Digital thermostats have their own issues. Dead batteries are the most common—and the easiest to fix. But we also see wiring problems, especially in older homes where someone installed a smart thermostat without checking compatibility. If your furnace or AC uses a 24-volt transformer and the thermostat expects a different voltage, you'll get erratic behavior or no operation at all.
Location matters, too. A thermostat installed on an exterior wall, near a window, or above a heat register won't give accurate temperature readings. It'll call for heating or cooling based on a "hot spot" or "cold spot" rather than the actual home temperature.
Signs of Thermostat Problems
- Temperature swings—house gets too hot, then too cold
- HVAC system doesn't respond when you adjust the thermostat
- Blank or flickering display
- Thermostat reading doesn't match actual room temperature (test with a separate thermometer)
- System runs constantly or won't turn on at all
If you're experiencing constant running issues, check out our guide on why your AC won't shut off during Michigan summers.
Prevention Strategy
Replace thermostat batteries once a year (we recommend doing it when you change your smoke detector batteries). If you have a programmable or smart thermostat, review the settings periodically—sometimes a schedule gets set incorrectly, and the system behaves in ways you don't expect.
If you're considering an upgrade, modern smart thermostats like the Honeywell T6 Pro, Ecobee, or Carrier Côr can improve comfort and efficiency. But make sure a qualified technician installs it—improper wiring can damage your HVAC system's control board, which is a much more expensive repair. Our team at NEXT Heating & Cooling handles smart thermostat installations regularly and ensures compatibility with your existing equipment.
Cost Reality
Thermostat repair (calibration, wiring fix): $100-$300. Thermostat replacement: $150-$500, depending on the model. A basic programmable thermostat costs $150-$250 installed. A Wi-Fi smart thermostat with remote access and learning features runs $250-$500 installed. The investment often pays for itself through better temperature control and energy savings—we've seen homeowners in Troy and Bloomfield Hills cut their heating bills by 10-15% after upgrading from an old mechanical thermostat to a programmable model.
5. Condensate Drain Clogs
This is the repair most homeowners don't know exists until it causes a problem. Your air conditioner (and high-efficiency furnace, if you have one) produces condensation as it operates. That moisture has to go somewhere—usually down a PVC drain line to a floor drain, sump pump, or outside.
When that drain line clogs, water backs up. In a basement furnace room, that means water pooling around your equipment. In an attic air handler, it can mean water damage to ceilings and drywall. Most modern systems have a float switch that shuts down the AC if the drain pan fills up—which is a safety feature, but it also means you lose cooling on the hottest day of the year.
What Causes Condensate Drain Clogs
Algae and mold love the dark, moist environment inside a condensate drain line. Over time, a slimy biofilm builds up and restricts flow. Dust and debris from the air can also accumulate in the drain pan and get washed into the line. In Michigan, where humidity is high during summer months, condensate production is significant—a properly functioning AC can produce 10-20 gallons of water per day. That's a lot of opportunity for clogs to form.
We also see clogs caused by improper drain line installation. If the line doesn't have enough slope, water sits in low spots and encourages algae growth. If there's no trap or the trap dries out, you can get airflow issues that prevent proper drainage.
Signs of a Clogged Condensate Drain
- Water pooling around the indoor AC unit or furnace
- AC shuts off unexpectedly (float switch tripped)
- Musty or moldy smell near the air handler
- Water stains on ceiling below attic air handler
- Gurgling sounds from the drain line
If you're seeing water leaking from your AC unit inside the house, a clogged condensate drain is often the culprit.
Prevention Strategy
Pour a cup of white vinegar or a condensate drain tablet down the drain line every 3-6 months. This kills algae and prevents buildup. During annual AC maintenance, your technician will flush the drain line with a wet-dry vacuum or compressed air, inspect the drain pan for cracks, and check the float switch operation.
If you have a basement floor drain that the condensate line empties into, make sure it's not clogged. We've been on service calls where the AC drain was fine, but the floor drain was backing up from a sump pump failure or sewer line issue.
Cost Reality
Condensate drain cleaning: $75-$200. It's a straightforward repair—usually takes 30-60 minutes. If the drain pan is cracked or rusted and needs replacement, add $150-$400 depending on accessibility. If the clog caused water damage to your home, you're looking at additional costs for drywall repair, mold remediation, or flooring replacement—far more expensive than a $100 drain cleaning.
The Real Cost of Reactive vs. Preventive Maintenance
Let's talk numbers. The five repairs above—ignitor, refrigerant leak, blower motor, thermostat, and condensate drain—represent the majority of service calls we handle in Macomb, Oakland, and St. Clair counties. Here's what they cost when they happen as emergencies:
- Ignitor failure (emergency call): $300-$600
- Refrigerant leak (diagnosis and repair): $400-$1,500
- Blower motor replacement: $600-$1,200
- Thermostat replacement: $200-$500
- Condensate drain clog (with water damage): $300-$1,000+
Total potential cost if you experience all five over a few years: $1,800-$4,800.
Now compare that to preventive maintenance. The Next Care Plan costs $5 per month ($60 per year) and includes two annual visits—a fall furnace tune-up and a spring AC tune-up. During those visits, we catch ignitor wear before failure, identify refrigerant leaks early, test capacitors, calibrate thermostats, and flush condensate drains. Members also get 10% off repairs and priority scheduling, which means no waiting three days for service during a heat wave.
Over five years, you'd pay $300 for the plan. Even if it prevents just one emergency repair, you've come out ahead. And statistically, homeowners with annual maintenance avoid 60-80% of the emergency repairs that hit homeowners who skip tune-ups.
We're not saying this because we're trying to sell you something. We're saying it because after 35 years in this business, we've seen the pattern over and over. The homeowners who call us in a panic on the coldest night of the year are almost always the ones who skipped their fall furnace check. The ones who schedule regular maintenance? They rarely have emergencies.
When to Call a Professional vs. DIY
Some HVAC tasks are safe and appropriate for homeowners. Others require a licensed and insured HVAC contractor with specialized tools and training. Here's the breakdown:
Safe DIY Tasks
- Changing the air filter: Do this every 30-90 days. It's the single most important maintenance task you can perform.
- Replacing thermostat batteries: Annual task, takes 2 minutes.
- Clearing debris from outdoor condenser unit: Turn off power first, then remove leaves, grass clippings, and dirt from around the unit.
- Pouring vinegar down the condensate drain: Preventive measure, safe and effective.
- Resetting a tripped circuit breaker: If your HVAC system won't turn on, check the breaker panel first.
When to Call a Professional
- Anything involving refrigerant: EPA regulations require certification to handle refrigerant. DIY recharge kits are illegal in many cases and can damage your system.
- Electrical repairs: HVAC systems use 240-volt circuits. Incorrect wiring can cause fires or electrocution.
- Gas furnace repairs: Natural gas leaks are life-threatening. If you smell gas, leave the house and call your utility company.
- Ductwork modifications: Improperly sized or sealed ducts reduce efficiency and comfort.
- Compressor or heat exchanger issues: These are major components that require specialized tools and diagnostic equipment.
Michigan law requires HVAC contractors to hold a mechanical contractor license. That's not just bureaucracy—it's a consumer protection. Licensed contractors carry insurance, follow building codes, and have the training to work safely with high-voltage electricity and combustible fuels. When you hire a NATE-certified technician from a company like ours, you're getting someone who has passed rigorous exams on system design, diagnostics, and safety.
Ready to Prevent These Repairs Before They Happen?
NEXT Heating & Cooling has been keeping Michigan homes comfortable for over 35 years. Our NATE-certified technicians provide honest diagnostics, fair pricing, and no-pressure service. Join the Next Care Plan for just $5/month and get two annual tune-ups, priority scheduling, and 10% off repairs.
Schedule Your Tune-Up TodayFrequently Asked Questions
Most common repairs range from $150 to $600, depending on the component and whether it's an emergency call. Simple fixes like thermostat batteries or capacitor replacement are on the lower end ($100-$300). More complex repairs like blower motor replacement or refrigerant leak repair run $400-$1,200. Emergency service outside normal business hours typically adds $100-$200 to the base cost. The best way to avoid high repair bills is preventive maintenance—catching small issues before they become expensive failures.
Yes—annual maintenance prevents 60-80% of emergency repairs. During a tune-up, technicians inspect components for wear, test electrical connections, measure refrigerant levels, clean coils, and identify problems before they cause system failure. For example, replacing a worn ignitor during scheduled maintenance costs $150-$250. Waiting until it fails on a Sunday night in January? That same repair costs $400-$600 as an emergency call. The Next Care Plan includes two annual visits (fall furnace tune-up, spring AC tune-up) for just $5/month—far less than one emergency repair.
A repair fixes a specific component—ignitor, capacitor, thermostat, etc. A replacement means installing a new furnace or AC unit. The decision comes down to the "50% rule": if the repair cost is more than 50% of the replacement cost and your system is over 12-15 years old, replacement is usually the smarter investment. For example, if your 18-year-old furnace needs a $1,800 heat exchanger repair and a new furnace costs $3,500, replacement makes more sense. You get a new warranty, better efficiency, and avoid throwing money into an aging system. Our team provides honest recommendations—we'll never push you toward replacement if a repair makes sense.
Yes. NEXT Heating & Cooling offers 24/7 emergency service throughout Macomb, Oakland, and St. Clair counties. If your furnace fails during a polar vortex or your AC quits during a July heat wave, we'll get a technician to your home as quickly as possible. Next Care Plan members get priority scheduling, which means faster response times during peak demand. Emergency service does cost more than scheduled repairs—typically $100-$200 additional—but when it's 10°F outside and you have no heat, that's a small price for peace of mind.
Every 30-90 days, depending on your home. If you have pets, live on a dirt road, or run your system frequently, change it every 30-60 days. Homes without pets and with good indoor air quality can stretch to 90 days. A clogged filter is the number one cause of preventable HVAC problems—it restricts airflow, which makes your furnace or AC work harder, increases energy bills, and shortens equipment life. Set a reminder on your phone or sign up for a filter subscription service. It's the easiest and cheapest maintenance task you can do.
We service all major brands—Carrier, Lennox, Trane, Rheem, Bryant, Goodman, Amana, York, and RUUD. Our technicians are NATE-certified and trained on the specific diagnostic procedures and parts for each manufacturer. Whether you have a 20-year-old Carrier furnace or a brand-new Lennox variable-speed system, we have the expertise and parts access to handle the repair. We're also authorized dealers for several brands, which means we can offer manufacturer warranties on new installations.
For most homeowners, absolutely. At $5/month ($60/year), you get two annual tune-ups (fall furnace, spring AC), priority scheduling, and 10% off all repairs. A single tune-up visit costs $120-$150 if purchased separately, so the plan pays for itself immediately. But the real value is in preventing expensive repairs. Members avoid 60-80% of the emergency breakdowns that hit homeowners who skip maintenance. Over the life of your HVAC system, that's thousands of dollars in avoided repair costs. Plus, regular maintenance extends equipment life by 3-5 years and improves efficiency by 10-15%, which lowers your monthly utility bills.