Is Your Furnace Not Blowing Hot Air? 7 important things to consider

Is Your Furnace Not Blowing Hot Air? 7 Important Things To Consider
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The AC Therapist

Warning: Is Your Furnace Not Blowing Hot Air? 7 important things to consider

If you’re like me, you’ve probably spent the last few days cranking up the thermostat to try to stay warm now that winter is finally here. But if you’re still shivering, there might be something wrong with your HVAC system. We’ll walk through some of the most common issues preventing heat from getting through and get your AC back on track!  

The thermostat is off.  

If you’ve determined that the thermostat is set to the right temperature and still isn’t working, your next step is to check if it’s off. If you’re not sure how to check for this, there are a few things you can try:  

  • Check the thermostat display. Many modern thermostats have a button or switch that lets you cycle through a series of settings: off, cooling mode, heating mode, and vacation mode (also called “hold” or “lockout”). Make sure that this button hasn’t been turned off by mistake.  
  • Try pressing buttons on an older-style mechanical thermostat. These mechanical models typically work with levers or knobs instead of digital displays; these buttons may be labeled as heat/cool/off/fan speed up/down.  


The blower unit needs cleaning.  

 If you’re still not feeling the heat, it may be time to clean your blower unit.  

The first (and most obvious) step is to check the filters on your unit. Did you know that air conditioning units have two types of filters? The first type, an “air filter” or “outdoor coil filter,” is found inside your home and cleans the air before it passes through into the living space. This can be accessed by removing a panel near where you plug in your unit. The second type is called an “indoor coil filter” and sits outside at the base of your system.  

This one keeps dirt from entering through cracks around pipes or doors so that dirty air doesn’t get sucked into your HVAC system when you turn it back on again after shutting off power during maintenance work like replacing parts or cleaning coils with fans blowing against them outdoors.  If both types are clean already, then try the next steps.  

The air filter is clogged.  

To check if your air filter is clogged, remove it from its housing and look at it. If you see dust or debris on the filter’s surface, you need to clean it. To clean your HVAC filter, use a vacuum cleaner with a soft brush attachment to remove as much dust as possible from both sides of the filter. You should also remove any loose dirt around the edges of your furnace unit’s grille while cleaning your filters.  

You should replace an air filter every 6 months or so (or more frequently if needed), depending on how often you use your heater/cooler throughout each season. Suppose you keep your air filters the same regularly. In that case, this can lead to lower efficiency in heating systems due to higher amounts of trapped dust particles blocking air flow through vents–which may cause additional problems like mold growth inside walls where ducts run between rooms!  


The gas valve is closed.  

The gas valve is a safety feature that prevents gas from escaping into the air when the unit is not operating. It’s normally open when the furnace is running but can be closed manually or automatically by a thermostat.  

The switch controlling the blower is turned off.  

The switch controlling the blower is located in the furnace and will be labeled as such. Depending on your model furnace, it might also be a button or knob. If you have an HVAC technician come to look at your system, it would be helpful for them to know that this is the first thing they should check if the fan isn’t working properly.  

 Check the furnace igniter.  

If your furnace isn’t heating at all, or it’s only blowing out a small amount of heat, there’s a good chance that the problem lies with the igniter.  

 The igniter is an electrical device that lights the gas burner in your furnace. If you can’t light it up (or don’t have any flame), then there’s no way for heat to be produced. It may also be bad if you have very low levels of hot air from your vents, even though they’re set to full blast, and you’ve tried resetting everything multiple times.  

 Typically, the igniter will be mounted on top of your furnace or near its base; in some cases, it may even be located inside nearby ductwork where it connects with wires leading into fuses or breakers inside an electrical box near where gas lines enter buildings through walls made from sheet metal panels.

Check the furnace’s pilot light.  

 The pilot light is the small flame inside your furnace. It’s turned on and off by a switch so that it can be lit when you want to start heating your house. The furnace needs this flame to ignite the gas and start working. If your pilot light has gone out, see if you can reignite it using a match or lighter.  

 If relighting the pilot isn’t enough, check your thermostat settings: do they need to be adjusted? If so, adjust them accordingly—and try lighting the pilot again!  

 These are some of the common issues preventing hot air from blowing through your HVAC system.  

  • Your thermostat might be set to a lower temperature than the furnace.  
  • The blower unit needs cleaning. Since hot air is being pushed out of the system, you should check that there aren’t any blockages in the ductwork or vents that would prevent that airflow from reaching your home.  
  • The air filter may be clogged with dust and particles, causing it to restrict airflow and prevent hot air from circulating throughout your home. Check the filter regularly and replace it whenever necessary (usually once every three months).  
  • If you have an older system with a gas valve instead of an electronic ignition, make sure that it’s closed completely before starting up again after turning off power for maintenance purposes; otherwise, gas could leak into your home if there is still some pressure behind the valve when opening it back up again!  



This has helped you figure out the cause of your HVAC system not blowing hot air and how to fix it. If you’re still having trouble, contact a professional or go back to the basics and ensure everything is plugged in properly. 

Check here what the SEER 2 rating means for homeowners in Florida. 

The AC Therapist is here to help you!

We, at The AC Therapist, are prepared to accompany our customers in this process and offer them the best efficient units to save money while obtaining a high-efficiency system. Give us a call and get a free estimate!

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