Why Is My Heating Blowing Cold Air? Here Are 10 Reasons

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Southern California may not have to deal with bitterly cold winters like our friends further north.

We still need reliable heat!

You need that furnace to function when the temperature drops into the 40s or below at night from December through February. Remember the record-breaking cold front last year? Yikes!

For older folks and people with compromised immune systems, a broken furnace is a critical safety issue.

If your heater is blowing cold air, run through this checklist to find the solution.

Why Is My Heater Blowing Cold Air? 

A message about having a heating upgradeHVAC systems are intricate pieces of machinery. With so many parts, things often go wrong and need to be updated or replaced. Here are some of the most common reasons:

1) Check the Thermostat Settings

It sounds simple but sometimes the most obvious fix is the correct one.

Make sure your furnace isn’t set to “on” rather than “auto.” A thermostat set to “on” will continue blowing air even when the furnace isn’t producing heat. 

You should also double-check that no one has accidentally switched the thermostat to “cool” rather than “heat” like the kids or grandkids.

If you recently installed a new thermostat, there’s a chance it’s not compatible with your HVAC system. Give us a call to check it out.

2) Reset the Furnace

Newer furnaces with computers built into the thermostat may need to be reset if the power goes out or if something glitches. 

Just as you would with the Wi-Fi router, turn the furnace off, wait a few minutes, and turn it back on. 

Resetting the system will reboot the internal software. 

3) The Air Filter Needs to Be Changed

Air filters are important. 

When an air filter doesn’t get replaced, dust and dirt continue accumulating. Not only does this mean air can’t flow through the filter properly, but it also means your furnace struggles against an uphill battle.

With regular use, you should replace your furnace filter

  • Every 90 days for homes with no pets
  • Every 60 days for homes with one pet
  • Every 30 days for homes with two pets OR someone with allergies or asthma
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Air filters are one of those things where quality DOES matter. Polyester or pleated air filters are ideal for filtering out pollution and contaminants to keep your air clean and your furnace strong.

4) The Pilot Light Went Out

Most systems rely on fuel to heat the air for your home. To heat the fuel, your furnace has a pilot light. If the pilot light goes out, your heating will start blowing cold air.

It’s not uncommon for these lights to go out occasionally. You should be able to check the bottom of your furnace to see if the light has gone out. 

If you don’t see a flame, start by turning off the thermostat. Next, you’ll relight the pilot. Most modern furnaces will have a special button, but older ones will require you to physically light it yourself with a lighter.

5) The Ductwork Is Leaking

Heating ductsEach type of ductwork is vulnerable to leaks. Energy Star estimates that in an average home, the ductwork leaks up to 30% of the air! 

Flexible ductwork is most vulnerable because it can tear. However, sheet metal is not immune to leaks either. 

When your ductwork leaks, it pulls surrounding cold air in. When it’s cold outside, the air floating around your attic and crawlspace is extremely frigid because it lacks proper insulation. 

The cold air mixes with the hot air from your furnace and pulls the temperature down. That’s a common reason for heating blowing cold air.

If you haven’t had your ductwork checked recently, give our experts a call at Home Comfort USA. We can run a thorough inspection, seal up any leaks, and clean out all the grime from your ductwork before it blows into your breathing air.

6) The Condensation Line is Clogged

Energy-efficient furnaces might be great for the environment (and your wallet), but they also come with a few unique issues.

One problem, in particular, is the condensation line.

During the heating process, energy-efficient furnaces produce condensation. Sometimes a lot of it!

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The furnace has a drainage line to remove the water, but these lines can get clogged. With nowhere to go, the water backs up and your furnace will stop heating the air. No good.

7) The Furnace Isn’t Drawing Enough Gas

If there’s a problem with your gas line, your furnace might shut itself off for safety reasons. However, the blower might continue running, which would lead to your heating blowing cold air.

Keep an eye (or nose) out for any natural gas smells and call the professionals to check it out.

8) Faulty Parts

Like cars, HVAC systems involve several moving parts and require tune-ups. Things break down. That’s life!

Common faulty parts (and quick fixes) that result in your heating blowing cold air include:

  • Dirty or broken gas valves
  • Faulty thermocouples (usually the case when your pilot light won’t stay lit)
  • Broken electronic ignition 

While these parts and labor aren’t outrageously expensive, it’s still dangerous to attempt them yourself, so give us a call.

9) The Oil Filter Is Dirty

Some older homes still use furnaces that rely on oil instead of gas to heat the air. Oil-powered furnaces have a second filter specifically for the gas that gets dirty and gross.

10) You Need an Upgrade

Sometimes, older systems are simply not worth repairs. If your heating keeps blowing cold air, it might be more cost-effective to replace the system rather than repairing it. 

Plus, newer HVAC systems are energy efficient, so you can save a ton of money on your heating bills each month and possibly even take advantage of a tax credit!

Heating Still Blowing Cold Air? Call the Professionals to Help

If you’ve already troubleshot your heating system blowing cold air and don’t feel comfortable running some of the other checks on the pilot or parts, give us a call at Home Comfort USA. Our expert technicians will check for ductwork leaks you can’t see and give your system a thorough tune-up! Most repairs aren’t too costly either.

Don’t suffer through winter without proper heat! Contact Home Comfort USA to schedule an appointment now.

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