Why is my heat blowing cold air?

It’s cold out. You turn on your heat. It’s not getting warmer. Why is my heat blowing cold air? It’s a chilly problem that no one wants to deal with. There are several possible causes why cold air is coming out of your vents. It’s hard to guess what is going on without a technician looking at your equipment. But here are 3 common causes and what you can do to fix the problem.

  • The thermostat is set to “ON”. Is your heat blowing cold air only sometimes? Is the blower running constantly? Check your thermostat. That’s where the technician goes first – and so should you. If your thermostat is set to “ON”, the blower will run constantly even when the unit isn’t heating the air. Solution: Turn thermostat setting to “AUTO”. Now you should only feel warm air!
  • Unit is overheated. Your heat blows hot air, then cold air, but then it stops blowing air at all. Your system may be overheated. If so, the limit switch, a safety device, will turn off the unit. The blower keeps blowing to cool the unit down to a safe level. Most common cause for a system to overheat is a dirty air filter. The dirty air filter will block airflow, causing the system to run longer to heat your home until it overheats. DO NOT ignore this problem. Solution: Change your air filter immediately and do it every month! Repeated overheating will damage the heat exchanger, which is expensive to fix.
  • Pilot light is out on gas furnace. If your gas furnace is only blowing cold air, the pilot light may be out. Solution: Relight the pilot light. If the flame stays on, great! If it refuses to light, ensure that gas is flowing into the furnace. Make sure gas valve is on. If it lights but won’t stay lit, then you may have a problem with the thermocouple (the copper rod). It needs to be adjusted or replaced. Please call a professional for this.

If you still can’t figure out “why is my heat blowing cold air,” call one of our professional technicians here at LHT Cooling, Heating & Re


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North Myrtle Beach HVAC & Refrigeration

LHT Cooling, Heating & Refrigeration is a North Myrtle Beach HVAC and commercial refrigeration company serving the South Carolina Grand Strand, Carolina Shores and North Carolina. LHT services and repairs heat pumps, heating units, air conditioning units, furnaces, ventilation systems, indoor air quality, humidifications, ductless systems, boilers, reach-in coolers, walk-in coolers, reach-in freezers, walk-in freezers, ice machines, blast chillers and refrigerated displays.

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