My furnace can’t keep up! Nothing is worse than your furnace struggling during a cold spell in Oklahoma. Our weather is so unpredictable, sometimes it’s hard to know if you’ll be using your AC this week or your furnace. Once you notice your furnace is struggling to keep up, address it immediately to prevent any further damage to your system!

A quick online search can give you many answers to a furnace that is not putting out enough warm air, including:

  • It’s your dirty filter!
  • It’s your broken thermostat!
  • It’s your heat exchanger!

At Norman Air, we would love to tell you it is always a simple answer. However, there are many factors that go into a furnace failing to heat properly or struggling to keep up during cold months, and the symptoms can be varied.

Keep on the lookout for these issues because they indicate problems with the overall system.

Poor Temperature Control

The temperature is supposed to be even throughout your Norman home unless zoning systems are in place. If this is not the case, your HVAC technician should do a thorough inspection as the cause can be complicated.

Higher Bills

When homeowners have underperforming heating or cooling units, they often have higher utility bills. This is a sign that the unit is working too hard to produce enough heating or cooling for the home! As an HVAC unit ages, this is a common situation.


There can be alarming noises when parts of a furnace or AC slip or break. Homeowners often hear these noises and assume the worst. The immediate fear is that the repair will be expensive. This is not always the case, especially when you call a technician out immediately!

Waiting to make repairs can open the door for more damage to be done — THAT is what raises the repair bill!

Poor Air Quality

Finally, indoor air quality worsens when your furnace or air conditioner cannot keep up with your needs. Increases in allergy symptoms, extra dust in your home, and air pollutants occur when the air quality lowers. This can lead to chronic coughs, nasal dryness, and frequent sneezes.

Causes Of An Underperforming Furnace

Dirty Filters
Yes, dirty filters contribute. Before you call us, check that your filter is not dirty and that you have the proper filter in place.

Filters with a high MERV rating will restrict airflow and cause your furnace to work harder than it needs to (causing wear and tear on your unit AND higher utility costs). Dirty filters also cause the circulation of dust and other contaminants throughout your home. Check your filters monthly!


Your thermostat determines the temperature of your home, which means if it stops working, it cannot communicate with the furnace or AC to tell it when to turn on or off. This usually presents as frequent cycles, or a lack of heat when you need it most.

Keep an eye on your thermostat settings to ensure the system turns on and off when you want. If your thermostat causes your system’s inability to keep up, it needs to be replaced.

It is common to see user errors with WIFI/digital smart thermostats. Settings are complicated — if you suspect your problem has to do with your settings, we are happy to troubleshoot the system and show you how to properly set your thermostat settings.

Heat Exchanger

Heat exchangers use heat created by burners to warm the air inside your unit. From there, the newly warm air travels through the vents and into your home.

Problems with the heat exchanger often leave homeowners with no heat but also open the door to dangerous carbon monoxide exposure. Additionally, if the furnace blows out cold air, the heat exchanger is typically to blame.

Blower Belt

Blower belts allow the mechanics to work as intended. If the belts fray or slip, the furnace encounters problems. In addition, loud squeals originate from a belt with frays or when it slips.

This can be a quick repair and is not as alarming as it sounds unless it is left unattended. Do not ignore any sounds your HVAC system is making. It is better to get it investigated before the problem worsens!

Lack Of Furnace Maintenance

Prevention is worth its weight in gold! 85% of AC and furnace repair calls could have been prevented by regular maintenance. By scheduling routine tune-ups, you can save yourself from trouble later on. Our technicians can make sure you avoid having issues in the first place and that your system is running smoothly.

Unit Size

If your furnace can’t heat your entire home, the size may have something to do with it. A furnace too small for your space cannot properly heat the whole home, and a furnace too big wastes energy by providing more airflow and heat than the home, and ductwork is built to accommodate.

Sizing issues are only corrected with heating system replacement.


Sometimes, even though you have properly maintained your unit, parts just wear out over time! If you find yourself calling in a repair often and your utility costs continue to rise, it is likely time to replace your unit.

Norman Furnace Experts

At Norman Air, we promise to properly troubleshoot your issues and, if a furnace replacement is necessary, size your unit to your home. Once your furnace is repaired or installed, we guarantee proper airflow and temperature control.

Give us a call if you are ready to explore your repair options or get an online replacement estimate.

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