ABC Blog

Furnace Turns On But No Heat

a living room with a fireplace

The low “whoosh” of a furnace kicking on brings a sigh of relief when the temperatures drop. But, it’s a shock when your furnace turns on but there’s no heat. If your furnace is not putting out the heat you need, there are a couple of things you can check.

Check the Switches

First, take a look at your thermostat. It might seem obvious, but sometimes, a homeowner has accidentally clicked “cool” rather than “heat.” Luckily, if that is the case, it is an easy fix to click the switch to the correct function.

Your thermostat has another toggle that can just as easily be the reason for the flow of cool air in the cold weather. The location might vary, but somewhere on the wall thermostat is a switch that says “Auto” and “On.” A switch on “Auto” will make the furnace click on only when a sensor signals that the temperature in your home has fallen below the one you set, sending warm air throughout your ducts and through the vents, keeping you cozy. But if the switch is “On,” the heater won’t turn off, regardless of whether the unit is in a heating cycle. Again, a quick shift of the switch will get your furnace back on track.

If you have checked all the settings on your thermostat and they look correct, but you are still feeling cool air, your issue could be that the furnace isn’t getting good airflow. When was the last time you changed the filter for your unit? Maybe it’s been several months, or maybe you can’t even recall when you last put in a new filter. Keeping track of filter changes is more important than you might think. A clogged filter blocks the flow of air in your furnace, reducing its efficiency and potentially causing bigger problems.

Focus on the Filter

A dirty, clogged filter not only pushes dust and other particles back into the air you breathe, but it can also damage the parts of your HVAC unit. Over time, this can cause your unit to malfunction, overheat or fail entirely. How often you change the filter in your furnace depends on several factors. Where you live affects the lifespan of a filter. In climates that require the HVAC to run regularly, you will need to switch out your filter monthly for peak efficiency. A moderate climate might mean you only need to use your unit every now and then, which will give you more time before a filter swap is needed.

An HVAC for a smaller home doesn’t need to heat or cool as much space, so filter changes don’t need to happen as often. If you live in a larger home, the unit is doing a lot of work and will benefit from more frequent filter updates. Does someone in your home suffer from allergies, or do you have pets? Both of these situations will factor in to how often you will need a new filter for the HVAC. When in doubt, try putting in a new air filter and see if that helps improve airflow and get the warm air moving.

Other Quick Checks

Small things can be the reason you aren’t getting warm air through your vents. It is worth the time to take a look at your heat registers and make sure they are open, silly as that might sound. These aren’t something you generally notice, so if they have been bumped or otherwise closed, you might not realize it until it gets chilly in your home.

You might also want to try hitting the red reset button you can find on any furnace. That might get things working properly. But, if you are having to push that button often just to keep the warm air flowing, give a licensed professional a call so they can find the root of the problem.

If you have checked everything above and your furnace is still blowing cold air, it’s time to contact the professionals! Of course, if you would rather not have to deal with any of the self-checks, a local expert can diagnose your heating issue and get to work on fixing it.

a homeowner changing their furnace filter

How Often To Change Furnace Filter?

On average, homeowners should change their furnace filters once every three months. However, there are a number of factors that can affect how frequently your filter should be changed. Some of the factors that can influence how often your furnace filter needs to be changed include:

  • The size of your home. Larger homes will need to have filters changed on a more frequent basis because there is more air being pushed through the filters. Therefore, the filters are catching more debris.
  • The age of the people in your home. If you have young children in your home, you’ll want to change your air filter at least once every two or three months.
  • The number of pets in your home, if any. We love our furry friends, but they can introduce additional dander and smell into a home. If you have pets, you’ll want to change your filter more frequently.
  • The quality of your filter. If you’re using a less expensive fiberglass filter, it’ll likely need to be changed once every 30 days. However, if you’re using a high-end pleated filter or a HEPA filter, it can last you up to six months! Keep in mind, these are guidelines that don’t take into account other factors.
  • The climate. If you live in a mild climate, you probably aren’t running your heater or air conditioner as often, so you don’t have to change your filters as often. Here in Texas, our air conditioners work hard for the majority of the year, so filters get dirtier, quicker.

Another thing to consider is if anyone in your home has asthma or allergies. If someone in your home does have asthma or allergies, you’ll want to change your filter as often as once every six weeks.

While changing your filter can easily fall on the backburner, it’s important to stay on top of a regular schedule. Not only does it improve the quality of the air in your home, but it can also prevent AC repairs down the line.

a professional providing a furnace tune up

What Is A Furnace Tune Up?

The best way to make sure your system is winter-ready is to contact a licensed professional for seasonal HVAC maintenance. Just like you get your car looked at regularly, you should get your HVAC checked out twice a year.

An HVAC expert will look at your vents and air intakes, checking for blockages and removing anything that is getting in the way of airflow. Generally, such a once-over will also include an inspection of the following:

  • Heat exchanger
  • Blower
  • Blower motor and what amp it is drawing
  • Electrical connections, for loose or damaged wiring
  • Burner or flame sensor, if your furnace is gas-powered
  • Belts, looking for damage or cracking
  • Thermostat and its calibration
  • Air filter
  • Safety controls and startup cycle

You get more than just a visual inspection with your AC preventative maintenance. The licensed professional you choose will lubricate all of your HVAC’s moving parts: motors, bearings, fans and air circulators. They will measure the motor’s current and voltage to ensure they are operating at peak efficiency. Your system controls will be tested, as will the air for any presence of a carbon monoxide leak. All electrical wires and gas connections, if you have that type of unit, will be tightened. For a gas furnace, the professional also will check the gas pressure and burner combustion to make sure they are working as they should. They will also look over the flues and ventilation to ensure the gas is venting properly and safely.

After the inspection and tune-up, the professional will explain what they did and any problems they found. Plus, they will give you a detailed report on what they did and anything they recommend that you consider. For example, they may recommend changing the way you use the system or making heating repairs or upgrades. HVAC technology is always evolving, so you might not be aware of things you can add that will increase the unit’s efficiency and maybe even save you money down the line!

Talk with the pro you pick about what exactly is included in their recommended maintenance package. It is definitely a good idea to have everything looked over before the cooler weather swoops in. This way you aren’t left in the cold while waiting for a broken unit to be repaired! A tune-up is recommended for all types of heating units, from HVACs to heat pumps and even old boilers.

ABC Can Make Your Home Comfortable Again

Without a functioning heater or air conditioner, the members of your household can quickly get uncomfortable. If you’re having issues with your unit, contact ABC Home & Commercial Services. We can make repairs, provide preventative maintenance and can even offer honest advice on when to replace your air conditioner.

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