Furnace Blowing Cold Air

Why is Furnace Blowing Cold Air?

The autumn is here, and you are preparing for your cozy winters. When you turn the furnace on, you feel the cold air blowing, making you shiver. Your worst nightmare has come true, and you donot know what to do.

Do you try to fix it yourself? Do you call emergency furnace repair services?

Hold on, we will answer all your questions. Keep reading to know why your furnace is acting weird and what you can do to make it right before you FREEZE.

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Reasons for Furnace Blowing Cold Air

Let’s look at all the potential reasons for your furnace blowing cold air. Note that you should still hire an HVAC technician to diagnose the root cause.

1. The furnace might not be warm enough yet

If you have switched on your furnace for the first time after a 5 to 6-month gap, your furnace might take time to warm up. The logic behind it is just like heating up water, and it takes time to reach the boiling temperature. So, your furnace will need several minutes to blow out the desired hot air.

If the cold air is still flowing out after a good 15 minutes, the problem might be different so keep reading to find out.

2. The thermostat is not set to the right temperature

Thermostats are the first place you must check if your furnace is blowing out cold air. It is common to set your thermostat in the wrong mode when transitioning from summer to winter. You probably have your thermostat set to the cooling mode rather than the heating mode.

Here’s a tip: Check that your thermostat is set to ‘Auto’ instead of ‘On’. If it’s on ‘On’, the fan might keep blowing even when the heater isn’t heating. But if it’s on ‘Auto’, the heater and fan should work together like they’re supposed to.

3. Filter of the Furnace is Dirty

A furnace has something called an air filter which catches all the dust and debris of your home. This means a filter will get dirty and has to be changed periodically. When the filter is clogged with dirt, it stops the hot air from moving through the furnace properly. This can make your furnace overheat and shut off. And instead of warm air, you might feel cold air coming out of the vents!

This is a problem you can check for yourself without the help of a professional. Just turn off the furnace and check the filter. If it is dirty, change it, and repeat the same every 90 days. Changing this filter falls under regular maintenance. If the filter is not changed in time, you will face more expensive repairs down the line.

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4. You are dealing with an Overheated Furnace

If your furnace gets too hot, it will automatically shut down due to its safety feature. In this situation, shutting down is actually good as it helps the furnace from getting more damaged. This feature helps your furnace So, instead of blowing warm air, it might blow cold air or just stop working altogether.

A filter block could be a reason for your system to heat up, but there are other reasons, too.
Firstly if your air filter is dirty, the dirt might have spread out to other parts of the system, like the fan. This leads to a blockage in the airflow, leading to the furnace heating up.

Secondly, sometimes, in older furnaces, there can be wear and tear in the mechanical parts, which can lead the furnace to heat up.

Thirdly, furnaces usually last up to 15 years, even with proper maintenance. Some parts like the burner or the gas supply, might not work properly or stop working, leading to the heat up.

If your furnace is blowing cold air or acting weird, it might be overheating because of these reasons.

5. The Pilot Light is Always Going Out

This problem mostly happens with older furnaces because the newer ones only turn on the pilot light when needed. If you are confident enough and think you can successfully relight it by following the instructions that came with your furnace. Go ahead! Remember to turn of the gas before doing it.

Replacing pilot lights is not a piece of cake and must be done by professionals who know what they are doing. If you want to do it, please read the booklet that comes with your heating system carefully.

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6. The Gas Supply Has Problems

If you have a gas furnace at home, it will require a good amount of continuous natural gas or propane to work properly. If there are any problems with the gas supply, the furnace will not work. Furthermore, if the pilot light goes out completely, it means there is no gas supply, and the furnace will not work.

If the gas supply is not enough, your furnace will either blow out normal-temperature air or not work at all. The reason behind this could be that there’s not enough gas in your tank, or there might be a problem with how the gas gets to your furnace. These problems are not something you can solve with DIY. A gas supply problem requires the attention of an HVAC Technician immediately.

7. There is A Leak In The Air Ducts

Air Ducts are these tubes that carry the air around the house. If these tubes have leaks in them, the hot air will pass out before reaching you or the other living areas. In this situation, the fan will blow out normal room temperature air even though the furnace is on and working fine.

This can happen if the air ducts have become old or it is due to small animals clawing on them. A leaking air duct can be fixed with the help of tape or replaced with a new piece. Either way, calling an HVAC professional to solve this problem is best.

8. A cracked heat exchanger

The heat exchanger is one of the most important parts of a gas furnace. This part is what separates the combustion process from the air you breathe. If the heat exchanger develops cracks, the combustion gases like carbon monoxide can leak into the air you breathe

When this happens, it’s not just a problem for keeping warm. It’s also a safety issue. Your will see your furnace blowing cold air due to a cracked heat exchanger and also releasing dangerous gases. Situations like these definitely require the intervention of an HVAC professional, and you might have to empty your property temporarily.

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For those who have been wondering why is your furnace blowing cold air, we have covered all the possible reasons. Some issues, like a dirty air filter, you can handle yourself with simple maintenance. However, more complex problems, like pilot light issues or gas leaks, require immediate attention and professional help.

Remember, your safety and comfort are top priorities when it comes to your furnace. It’s also a good idea to turn on your furnace before winter approaches so you can detect any problems beforehand and avoid being chilly during the winter or having to wait for repairs.

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Furnace Blowing Cold Air? Don’t worry, Call Heald Mechanical.

Don’t let a chilly home catch you off guard! Ensure your furnace is ready to keep you warm all winter long by scheduling a furnace repair in Sacramento with us at Heald Mechanical in Sacramento. Our team of licensed professionals will ensure your furnace is running efficiently and safely, giving you peace of mind during the colder months. Don’t wait until it’s too late-schedule your furnace service and repair today for a cozy and worry-free winter!


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