When you turn on your furnace and only feel cold air, it’s a clear sign something’s wrong. Homeowners in Hanover, MA know how quickly a chilly home can become uncomfortable, especially during New England winters. At Efficiency Plumbing, Heating & Air, we understand how frustrating it is when your furnace is not blowing hot air — and we’re here to explain what could be causing it and how to get your heat back fast.
Check the Thermostat First
Before assuming the worst, start with your thermostat. Make sure it’s set to “heat” mode and that the temperature is higher than your current room temperature. If the thermostat batteries are dead or the settings are incorrect, your furnace may blow cold air even though it’s technically running.
Modern smart thermostats can also lose their Wi-Fi connection or experience software glitches. Resetting your device or replacing the batteries can often solve the issue.
Clogged Air Filter Might Make Your Furnace Not Blow Hot Air
A dirty or clogged air filter is one of the most common reasons a furnace stops blowing hot air. Restricted airflow prevents your furnace from circulating warm air properly and can cause the system to overheat. When that happens, safety sensors shut off the burners to protect your furnace.
To fix it, check your air filter and replace it if it looks dusty or gray. Homeowners in Hanover should replace filters every one to three months, depending on how often the system runs.
Pilot Light or Ignition Problems
If your furnace uses a pilot light, check to see if it’s lit. A blown-out pilot light or a faulty ignitor can stop your system from producing heat altogether. Newer furnaces use electronic ignition systems that can fail due to dirt, corrosion, or sensor issues.
Never attempt to repair or relight the pilot if you smell gas — leave the area and call a professional immediately. The licensed technicians at Efficiency Plumbing, Heating & Air can safely inspect and relight your system if necessary.
Faulty Flame Sensor Might Make Your Furnace Not Blow Hot Air
The flame sensor’s job is to detect whether the burner is lit. If it’s dirty or malfunctioning, the system will think there’s no flame and shut down the gas supply. That means the fan keeps running, but no heat is produced — so you feel cool air from the vents.
Our technicians often find this issue during routine tune-ups. Cleaning or replacing the sensor usually restores full operation quickly.
Overheated Furnace
If the furnace runs too hot, it will trigger a safety limit switch that turns off the burners. The blower may continue running to cool things down, which causes the system to push out cool air instead of heat.
Common causes of overheating include:
- Dirty air filters
- Blocked vents or ductwork
- Malfunctioning blower motor
If your furnace frequently overheats, schedule a professional inspection. Continuous overheating can damage internal components and shorten the system’s lifespan.
Gas Supply or Valve Issues
Your furnace needs a consistent gas supply to create heat. If the gas valve is closed or there’s a disruption in the line, your furnace will blow cold air. Always check that the gas valve near your furnace is in the “on” position (parallel to the pipe).
If you suspect a gas leak, evacuate immediately and contact your gas company or Efficiency Plumbing, Heating & Air for emergency assistance.
Ductwork Leaks or Blockages
Sometimes, the furnace is heating properly — but by the time the air reaches your vents, it’s no longer warm. Leaky or damaged ducts allow heat to escape before it reaches your rooms. Blocked or disconnected ducts can also reduce airflow, creating uneven temperatures throughout your home.
Professional duct inspection and sealing can prevent heat loss and make your system much more efficient.
When to Call a Professional if Your Furnace isn’t Blowing Hot Air
If you’ve checked your thermostat, filter, and vents but still have no warm air, it’s time to call the experts at Efficiency Plumbing, Heating & Air. Our licensed HVAC technicians in Hanover, MA can diagnose the problem quickly, repair faulty components, and make sure your home’s heating system runs safely and efficiently.
We handle everything from minor repairs to full furnace replacements. Plus, we offer 24/7 emergency service for those unexpected cold nights when your furnace quits without warning.
Prevent Furnace Problems with Regular Maintenance
The best way to avoid your furnace not blowing hot air is through annual maintenance. Our team inspects burners, sensors, filters, and electrical connections to ensure your system operates smoothly. Regular maintenance helps prevent unexpected breakdowns, lowers energy costs, and extends the lifespan of your furnace.
Call Efficiency Plumbing, Heating & Air Today
Don’t let a cold home disrupt your comfort this winter. When your furnace isn’t blowing hot air, call Efficiency Plumbing, Heating & Air to get it running again. We proudly serve Hanover and surrounding Massachusetts communities with fast, reliable heating service you can count on.
