Heating Repair Checklist: What to Check Before Calling a Pro

When the cold bites and your furnace goes silent, panic sets in fast. The house cools down. Tempers go up. And every minute feels longer than the last. At Denny’s Heating, we know how stressful sudden heating failures are—especially during those deep winter nights when you just want your family safe and warm.

But before you reach for the phone to call an emergency hvac technician, try these quick checks first. Sometimes the fix is as simple as flipping a switch or changing a filter. Here’s a practical, step-by-step heating repair checklist anyone can use, straight from our residential service pros.

Check Your Thermostat 🕹️

Think of your thermostat as the remote control for your comfort. If it’s not set right, your system won’t know what to do.

What to do:

• Make sure the thermostat is set to “HEAT,” not “COOL” or “OFF.”
• Check the temperature setting. Is it higher than the current room temperature?
• Replace batteries if it’s a battery-powered model.
• Gently dust the face and around the unit. Sometimes, a buildup of dust can trip up the sensors.
• Listen for a click when you adjust the temperature—this signals your system is responding.

Safety Reminder:
Never poke inside or take apart your thermostat if you’re unsure. If the screen is blank or unresponsive after battery changes, call a professional.

Red Flags—Call a Pro If:

• The display is dead, even after new batteries.
• You smell burning or see scorch marks.
• The system cycles on and off rapidly (short cycling).

Want a deep dive?
The U.S. Department of Energy offers detailed thermostat troubleshooting guides for homeowners.

Inspect Air Filters 🦠

Clogged filters are like trying to breathe through a scarf wrapped tight around your face. Without airflow, your system can’t work properly and may even overheat.

How to check:

• Locate your main return air filter. It’s usually behind a grille in a hallway or near the furnace.
• Slide the filter out and hold it up to light. If you can’t see light through it, it’s time to change it.
• Replace with the same size and type. Note the airflow direction arrow.

Tip from the field:
Change filters every 1–3 months in winter, especially if you have pets or allergies.

Safety Reminder:
Turn off your system at the thermostat before removing the filter to avoid dust getting sucked into the blower.

Red Flags—Call a Pro If:

• The filter is wet, moldy, or disintegrating.
• You see ice inside the system or hear hissing.

The Environmental Protection Agency recommends regular filter changes to improve indoor air quality and system efficiency.

Reset Power & Breakers 💡

Sometimes the furnace just needs a fresh start. Like rebooting a stubborn phone, a power reset can clear minor errors.

Steps:

• Find your home’s electrical panel. Look for breakers labeled “Furnace” or “HVAC.”
• Flip the breaker off, wait 30 seconds, then flip it back on.
• Check for a separate power switch on or near the furnace—usually a simple toggle switch.
• Look for a reset button on the furnace itself (not all models have one).

Safety First:
If you see sparks, smell burning, or hear buzzing, stop immediately and call for emergency hvac help.

Red Flags—Call a Pro If:

• Breaker trips again right away.
• You hear loud popping or crackling from the unit.
• Furnace doesn’t restart after resetting.

Authoritative Reference:
National Electrical Code (NEC) guidelines stress caution around electrical panels. When in doubt, stay safe and let a licensed technician handle it.

Look for Airflow Issues 🍃

Blocked vents or closed registers are like pinching a garden hose—water can’t flow, and neither can warm air. Your system strains, making things worse.

Quick checks:

• Walk through every room. Are any supply or return vents blocked by furniture, rugs, or curtains?
• Open all vents wide—even in unused rooms.
• Check for visible dust buildup or objects stuck in vents.
• Listen for strange noises—whistling, rattling, or banging may signal a duct problem.

Safety Reminder:
Never reach deep into vents or ducts. Sharp edges and hidden screws can cause injury. If you suspect a blockage deep inside, call a duct cleaning specialist.

Red Flags—Call a Pro If:

• Vents blow cold air when heat is on.
• There’s little to no airflow, even with a clean filter.
• You smell must or mold from vents.

The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) recommends annual inspection of ductwork for leaks and blockages.

Quick Safety Checklist

• Is there a gas smell? Leave the house and call 911—don’t try to fix it yourself.
• Are there unusual noises (banging, screeching, humming)? Stop and call a pro.
• Is water pooling around your furnace? This could mean a leak or cracked heat exchanger—call for help.
• Never bypass safety switches or relays. These are there for your protection.
• Always turn off power before inspecting electrical components.

DIY vs. Call a Pro

You can handle simple checks—filters, thermostat settings, and vents. But when it comes to wiring, gas, refrigerant lines, or anything involving sheet metal and Hood & Exhaust Installation near you, it’s time to call in a licensed professional.

DIY is fine for:

• Changing filters
• Adjusting thermostats
• Checking breakers and power switches
• Opening or closing vents

Call a pro for:

• Electrical or gas issues
• Strange smells, leaks, or noises
• No heat after basic troubleshooting
• Repeated system cycling or tripped breakers

What Pros Do On Arrival

When Denny’s Heating arrives for emergency hvac service, here’s what you can expect:

• Full system diagnostic—checking controls, safety switches, and airflow.
• Testing gas or electrical connections for safety.
• Inspecting the heat exchanger for cracks or leaks.
• Checking thermostats, wiring, and relay boards.
• Verifying air balancing in every room.
• Providing clear options and next steps before any major repairs.

Our technicians follow local building codes and safety standards (like those from the International Residential Code) on every call.

Prevention & Maintenance

The best heating repair is the one you never need. Here’s how to keep your system running strong:

• Change filters regularly.
• Schedule annual furnace and HVAC maintenance.
• Keep vents and returns clear of obstructions.
• Test your thermostat at the start of each season.
• Consider professional duct cleaning or a home energy audit for older systems.

ASHRAE and EPA both recommend yearly maintenance for optimal performance and indoor air quality.

Costs & Time Factors

Heating repairs can take anywhere from a quick 10-minute filter swap to several hours for complex fixes. Costs depend on:

• Age and type of system (mini-split, furnace, radiant, geothermal, etc.)
• Parts needed (thermostats, igniters, filters, etc.)
• Labor time and emergency response needs (nights, holidays, etc.)
• Additional services like IAQ testing or sheet metal repairs

Most basic repairs are completed same-day. If special parts or Hood & Exhaust Installation near you are needed, it may take longer.

When It’s an Emergency

If your home is dropping below 55°F, pipes can freeze. That’s an emergency—especially for families with children, seniors, or medical needs.

Call Denny’s Heating immediately if:

• Your heating system won’t turn on and outside temps are below freezing.
• You smell gas or burning.
• Water is leaking from your furnace.
• You’ve lost heat and your backup generator won’t start.

For non-urgent issues (like a single cold room or noisy vent), call during regular business hours to save on after-hours charges.

FAQ

Q: Why does my furnace keep turning on and off?
A: This could be a dirty filter, faulty thermostat, or an airflow problem. If your quick checks don’t solve it, call a licensed technician.

Q: My heat is working, but some rooms are freezing. Why?
A: Blocked vents, closed registers, or unbalanced ductwork can cause uneven heating. Open all vents and check for obstructions. Persistent issues may need air balancing or duct inspection.

Q: Is it dangerous if my furnace smells like burning dust?
A: A dusty smell is common when first turning heat on for the season. If it doesn’t go away after an hour or two, or you smell burning plastic or metal, shut off the system and call for service.

Q: How often should I get my heating system serviced?
A: Once a year, ideally before winter starts. This keeps your system efficient and safe.

Local/Seasonal Considerations

Winter can be brutal. In cold snaps, heating demand spikes and so do wait times for emergency hvac repair. Schedule preventive maintenance in the fall and check filters monthly during heavy use. For homes using generators, check your generator maintenance schedule—don’t wait until the next storm.

If you’ve upgraded with mini-splits, heat pumps, or whole-house fans, remember these systems have their own unique troubleshooting needs. Contact a pro familiar with your equipment type.

When you’ve run through this checklist and your heat still isn’t working, don’t sweat it—or freeze! Denny’s Heating is here 24/7 for real emergencies, with technicians ready to restore your home’s comfort and safety at any hour.

Call Denny's Heating now — or reach us anytime at  888-840-5783 .