Why Is My Furnace Blowing Cold Air? (3 Quick Checks)

## Why Is My Furnace Blowing Cold Air? (3 Quick Checks) Nothing's more frustrating than cranking up your thermostat in Quincy or Weymouth only to feel cold air blowing through your vents. Before you panic, there are three quick checks you can do yourself before calling East Coast Air for professional furnace repair in South Shore Massachusetts. ### Check 1: Your Thermostat Fan Setting Many homeowners don't realize their thermostat has two fan settings: AUTO and ON. When set to ON, the fan runs continuously, even when the furnace isn't actively heating. This creates cold air between heating cycles. **The Fix:** Switch your thermostat to AUTO. The fan will only run when the furnace is actively producing heat. This simple change solves the problem for many Scituate and Marshfield homeowners. ### Check 2: Inspect Your Air Filter A dirty air filter is the number one cause of furnace problems in South Shore Massachusetts. When the filter gets clogged with dust, pet hair, and debris, airflow becomes restricted. This causes your furnace to overheat, triggering a safety shutoff. The blower fan continues running (to cool down the system), but no heat is being produced. Result? Cold air from your vents. **The Fix:** Check your filter monthly during winter. If it looks dark gray or you can't see light through it, replace it immediately. This is especially important in coastal areas like Cohasset and Hull where salt air can accelerate buildup. ### Check 3: Verify the Pilot Light (Gas Furnaces) If you have an older gas furnace, check if the pilot light is lit. A pilot light can go out due to drafts, dust buildup, or a faulty thermocouple. **The Fix:** Most modern furnaces have electronic ignition, but if you have an older model with a standing pilot, check your owner's manual for relighting instructions. If the pilot won't stay lit, call East Coast Air immediately as this indicates a more serious issue. ### When to Call East Coast Air If you've checked all three items and your furnace is still blowing cold air, it's time for professional help. Common issues requiring expert diagnosis include: - Failed ignition system - Broken flame sensor - Cracked heat exchanger (dangerous!) - Malfunctioning gas valve - Ductwork problems East Coast Air serves all of South Shore Massachusetts including Quincy, Weymouth, Bridgewater, Carver, Abington, Pembroke, Norwell, Hingham, Cohasset, Marshfield, Duxbury, Scituate, and Plymouth with 24/7 emergency heating repair. Don't spend another cold night guessing. Our certified technicians diagnose and fix furnace problems quickly. **Call East Coast Air for reliable furnace repair throughout South Shore MA.**