Strange noises, uneven heating, and the system failing to turn on are the most frequent furnace problems. These issues often stem from dirty filters, faulty ignition systems, or worn-out parts. Some problems, like changing a clogged filter, are easy to fix, while others need a professional's touch to keep your HVAC system running smoothly.
Regular furnace maintenance is key to avoiding many issues, and we recommend checking your furnace before cold weather hits. This can save you from surprise breakdowns and costly repairs.
Identifying Common Furnace Problems
Furnaces can have several issues that affect their performance, and we'll look at some homeowners' most frequent problems with their heating systems.
Thermostat Malfunctions
If your furnace isn't turning on or off when it should, check the thermostat first. Ensure it's set to "heat" mode and the temperature is higher than the current room temperature. If needed, replace the batteries. If the display is blank or shows weird symbols, you might need a new thermostat. Sometimes, loose wires inside the thermostat can also cause issues.
Pilot Light and Ignition Issues
For older furnaces with standing pilot lights, a dirty or faulty pilot can prevent the burners from lighting. If you can't see a blue flame, try relighting it. Newer furnaces use electronic ignition systems, which can fail due to wear or dirt buildup. Listen for clicking sounds when your furnace tries to start. No clicking could mean a flawed ignition system. If you hear clicking but no flame, the gas valve might be stuck.
Airflow Problems and Dirty Filters
Dirty air filters often cause poor airflow, so check your filter monthly and change it every 1-3 months. A clogged filter makes your furnace work harder and can lead to overheating. It also reduces the amount of warm air reaching your rooms.
Look for these signs of airflow issues:
- Weak air coming from vents
- Some rooms are colder than others
- The furnace runs longer than usual
Blocked vents or leaky ducts can also cause airflow problems, so ensure all vents are open and unobstructed.
Heat Exchanger and Flame Sensor Concerns
The heat exchanger is a critical part of your furnace, and cracks in this component can release carbon monoxide into your home.
Signs of a cracked heat exchanger include:
- Soot around the furnace
- Strange smells when the furnace runs
- Flu-like symptoms in family members
A dirty flame sensor can also cause your furnace to shut off soon after starting, and this safety device needs to be cleaned to work correctly. If your furnace starts but stops after a few seconds, a dirty flame sensor might be the culprit. Due to its delicate nature, cleaning it is best left to a professional.
Troubleshooting and Maintenance
Regular furnace care helps prevent breakdowns and keeps heating costs low. Let’s go through some steps for upkeep and problem-solving.
Performing Regular Maintenance
- Change furnace filters every 1-3 months.
- Clean vents and registers often to remove blockages.
- Check the thermostat batteries yearly.
- Ensure the area around the furnace is clear of items.
- Schedule yearly professional HVAC check-ups.
DIY Furnace Troubleshooting Steps
If the heat stops, check the thermostat and ensure it's set to "heat" and the right temperature. To test, try turning it up 5 degrees. If the furnace won't turn on, check the circuit breaker. If it tripped, reset it. Also, look at the pilot light on older furnaces. If it's out, relight it.
Listen for odd noises when the furnace runs; rattling could mean loose parts, and squealing might show belt problems.
When to Call a Professional HVAC Technician
Call a professional if you smell gas or burning, as these present safety risks. Also, get help if the furnace keeps turning off and on quickly as this could be a big problem. You also hire experts to help with electrical issues, and pros can also handle any work on gas lines or the heat exchanger.
Understanding Heating System Efficiency
Heating system efficiency impacts energy bills, comfort, and air quality, and there are key ways to optimize your furnace's performance and create a more comfortable home environment.
Optimizing Thermostat Settings
A smart thermostat can boost heating efficiency. We recommend setting the temperature to 68°F (20°C) when awake and lowering it by 7-10°F when asleep or away. This can cut energy use by up to 10% yearly.
Program your thermostat to match your schedule, raising the temperature 30 minutes before waking up and lowering it 30 minutes before leaving or going to bed. Avoid cranking up the heat when you're cold, as this will not warm your home faster and will waste energy. Instead, dress in layers or use blankets for quick warmth.
Reducing High Energy Bills
Regular furnace maintenance is key to lowering energy costs. During heavy use, replace or clean air filters monthly. Seal air leaks around windows and doors using weatherstripping or caulk to prevent heat loss. Add insulation to your attic and walls to keep warmth inside.
Additionally, if your furnace is over 15 years old, consider upgrading to a high-efficiency model. New models can be up to 98% efficient, potentially cutting your heating bills by 30%.
Improving Indoor Air Quality
Install a whole-house air purifier to remove pollutants. These systems work with your furnace to clean air as it circulates. You can also use a humidifier to add moisture to dry winter air, helping to prevent respiratory issues and static electricity. Aim for 30-50% humidity levels.
Clean your air ducts every 3-5 years to remove dust, allergens, and mold that can build up over time. This will also help your heating system run more efficiently.
Signs of Emerging Issues
Spotting furnace problems early can prevent costly repairs and keep your home warm. Watch for these key signs that may indicate issues with your heating system.
Unusual Noises and Short Cycling
Banging, rattling, or whistling sounds from your furnace are not expected, and these noises often mean loose parts or airflow problems. Pay attention to how long your furnace runs, and If it turns on and off quickly, this is called short cycling. It can happen when the furnace overheats or has a faulty thermostat. Short cycling wastes energy and puts extra wear on your system.
Inadequate Heating and Frequent Cycling
Cold spots in your home or a nonstop furnace are signs of trouble. Your furnace may be working too hard to meet demand, leading to higher energy bills and more wear on parts. Check your thermostat settings first. Make sure it's set to "heat" and at the right temperature. If the problem continues, your furnace might be losing efficiency.
Electrical Problems and Safety Concerns
A tripped circuit breaker or blown fuse can shut down your furnace. If this happens often, there may be an electrical issue, so don't keep resetting the breaker, call a professional to check it out. Flickering lights when the furnace starts up can also point to electrical problems, and this might mean the furnace is drawing too much power.
Safety should always come first. If you smell gas or hear a loud boom when the furnace starts, turn it off right away. These could be signs of a gas leak or a cracked heat exchanger, which are serious safety risks. Install carbon monoxide detectors near bedrooms as they can warn you of this odorless gas that faulty furnaces might produce.
Get in touch to arrange an annual furnace or heating system inspection.
