During the coming winter months, the temperature will drop significantly, and this is when we turn our heaters on for the first time in months. But, what if your gas furnace doesn’t seem to be producing any hot air at all? This is a sure sign that there is something wrong; let’s take a closer look at six possible causes and offer some advice on how to fix the problems.

  1. The Thermostat Settings are Incorrect

This may seem silly, but you may be surprised at how often an HVAC specialist is called to fix a furnace, only to discover that the thermostat has not been adjusted! Let’s face it, when the weather is cold outside, our demand for heat increases, and the thermostat must be adjusted to meet that need.

Another possible cause is the fan setting, which may be set to “On” when it will blow continuously for the entire day. This may be the reason why the home feels colder when you return home. This is easy to fix, simply flip the fan over to the “Auto” setting, and the fan will only demand heat when needed. In many cases, this simple fix will get the furnace blowing hot air into the home again.

Another common issue is that the temperature on the thermostat is set to a higher setting than the current temperature in your home. In some homes, multiple people will adjust the temperature without consulting others beforehand. This can lead to confusion because you may not be aware of the new temperature settings. So, it’s always a good idea to check the temperature settings carefully before you make any adjustments yourself.

If you’ve tried all of the above solutions and you still cannot make any difference to the temperature when you adjust the thermostat, there is one last thing to try. Take out the batteries, replace them with fresh ones, take off the cover, and give the unit a clean. Dirt and debris inside the thermostat can interfere with the sensors and give incorrect temperature readings to the furnace. If there is still no hot air, consider a recalibration for your thermostat or an upgrade to a smart unit for more precise control.

  1. You’re Being Impatient for Heat

If you have a larger home or an older furnace, it can take a little while to get the heat that you need. This is especially true if it is very cold outside and you want to get warm quickly. But, before you contact your local HVAC specialist, consider giving the furnace a little more time to see if that makes a difference. Hopefully, this will be enough, but it’s important to realize that it is normal for a heating system to blow cold air before it starts to warm up.

  1. A Dirty Air Filter

If you can’t remember when you last replace the air filter in your furnace, then this is a likely cause of your problems. Every furnace relies on a supply of air to circulate the treated air around your home. Gradually, this air filter will start to accumulate materials, including dust, allergens, debris, and more. These materials clog up the air filter and prevent the circulation of heated air. The full details to check and replace your air filter are in your owner’s manual. If you’ve misplaced this important document, check the manufacturer’s site for a pdf replacement. Once you’ve removed the air filter, look at the surface in the light, and if you can’t see any light shining through, it needs changing. As a rule of thumb, it’s a great idea to replace your furnace air filter every six months. But, if you have a larger family or pets in the home, you may want to replace the air filter more frequently.

  1. A Dirty Flame Sensor

If your furnace seems to be sending out cold air intermittently, this could be caused by a dirty flame sensor. When the flame sensor is dirty, it can cause inaccurate temperature readings that confuse the furnace. As a result, the furnace may produce cold air seemingly at random during heating periods. This is easy to fix if you have a little confidence and the owner’s manual to identify the flame sensor. Start by cutting the power to the furnace, remove the flame sensor, and clean away the soot and debris with an emery cloth. Don’t follow the advice that says you can use sandpaper because you could easily damage the component. Reattach the sensor once it is clean, restore the power and test the furnace. If you keep your flame sensor clean, change the air filter regularly, and invest in some annual HVAC maintenance, your furnace will be more reliable and efficient.

  1. The Pilot Light is Not Lit

Every gas furnace needs a lit pilot light to ignite the heater when the heat is needed in your home. The pilot light is supposed to be lit constantly, but there are certain times when it can be blown out. As an example: recent gas company maintenance work could lead to the pilot light going out in multiple homes at the same time.

Go to the furnace with your owner’s manual and locate the pilot light. If it isn’t lit, you can attempt to relight yourself, but you must follow the procedure carefully. If this becomes a regular occurrence, there could be a buildup of dirt or debris on the surface that is interfering with the connection. Cleaning could fix the problem, or you may need to check the gas supply line and make sure it is fully open.

If none of these solutions fix your pilot light problems, it’s time to call in an HVAC specialist. Dealing with gas supply issues is beyond the reach of even dedicated DIY enthusiasts, and it should not be attempted. A new thermocouple may be required, and that is a job for a qualified professional only.

  1. The Ducts Are Not Sealed

The furnace may not be the cause of your cold air supply problems. If your ducts are not sealed, the treated air can escape, and this will make the air feel cooler at the registers. Ductwork is complicated to work on yourself because many areas will be hard to access, and they may need professional cleaning. If you suspect this is your problem, contact a local certified HVAC specialist and ask about a health check for your system today.