Why Is My Heater Blowing Cold Air?

By now, most of us are getting tired of the cold, dreary winter weather, but there are still a couple of months to go before spring arrives. In the meantime, you’ll have to rely on your heater to keep your home at a comfortable temperature. It can feel like insult to injury when you turn up the thermostat, only to feel a blast of cold air coming out of the vents. Why is this happening, and what can you do to resolve it?

1. The Fan Is Off

If your heater isn’t producing warm air, the first thing to do is check the thermostat. If it’s set to “on,” switch it back to “auto.” Now, you should have heat again.

2. You Need to Replace Your Thermostat Batteries

Low batteries in digital thermostats are one of the most common issues that prevent your HVAC system from operating correctly. To determine if you have a low battery, check the display on your thermostat. There’s usually a low battery indicator such as a flashing light or an image depicting a drained battery. If the display is blank, the batteries have gone dead. Consult the owner’s manual for your thermostat to learn how to replace them.

3. Someone Has Changed the Thermostat Settings

If your heater is blowing cold air, it’s always possible another member of your household has accidentally adjusted the thermostat or switched it from heating to cooling. If you have a thermostat with a sensitive touchscreen display, someone could have easily lowered the temperature without meaning to. Before you immediately assume you need repairs, make sure the settings are where they’re supposed to be. The answer could be a quicker fix than you realize.

4. Your Pilot Light Has Gone Out

If you have an older furnace, an extinguished pilot light could be the source of your problems. Newer units typically have electronic pilot lights that can’t go out, but if your furnace is more than a decade old, this is one thing to check. Review the owner’s manual to determine how to access the pilot light and re-light it. If your pilot light won’t stay lit, call the professional HVAC team at Maichle’s for a service check.

5. Low Fuel

If you have an oil-burning heating system and haven’t refueled in a while, you might have run out of oil. By the same token, if your home uses gas heat, there could be a problem with the gas line that has caused the connection to your property to stop working. In either of these cases, contact your utility provider to ask for help.

6. There Are Problems With Your Ductwork

Leaky ductwork is another somewhat less obvious issue that can make your heat work less efficiently. If this is your issue, your heating and cooling will struggle to reach the desired temperature, and you might have uneven temperatures throughout your home. Your heating bills will also be higher than average in this circumstance. A trained HVAC technician can help examine and address this problem.

7. The Flame Sensor Is Dirty

Pilotless ignition furnaces use a safety feature called a flame sensor to keep the furnace burning once it starts. If you have a dirty flame sensor, your furnace will kick in and begin heating, but then turn cold relatively quickly. Cleaning the flame sensor should restore your furnace’s heating function, and you can call a service professional to take care of this repair for you.

8. You Have a Clogged Filter

Your HVAC system relies on an air filter to regulate the temperature of the air in your home, but many people neglect to clean or replace these filters regularly. Clogged and dirty filters force your heater to work harder to maintain the desired temperature, which can shorten its lifespan by causing it to run much less efficiently. One result of a filter clog is that the air doesn’t get properly heated before circulating in your home. Swapping out the dirty filter with a new one is an easy DIY fix for this issue, but read your manual first to make sure you have the correct size for your system.

9. There’s a Problem With the Limit Switch

The limit switch is another built-in safety device that can cause your furnace to blow cold air if it starts to malfunction. The limit switch’s job is to signal your furnace’s fan to turn on and off. A faulty limit switch might never tell the fan to switch off, and it can continue to run even after your furnace has completed a heating cycle. In this case, call us at Maichle’s for a thorough inspection and repair of the problem.

10. Your Heater Is the Wrong Size for Your Home

There is no such thing as a “one-size-fits-all” HVAC solution. A heater that is too large will cycle on and off too frequently, driving up your energy bills. Conversely, one that’s too small will never be able to keep up with your home’s comfort needs. If an inexperienced installer put in your unit, they may have calculated the load size incorrectly, which could lead to the problems you’re experiencing today. Many factors go into this equation, not just the square footage of your home. A knowledgeable technician can correct this issue by installing a new, energy-efficient unit that is sized appropriately for your property.

Call Maichle’s Heating, Air Conditioning & Plumbing to Get You Through This Winter

If problems with your heat have left you shivering in your home, contact the well-trained team at Maichle’s. We’ve been serving property owners in Delaware, Maryland and Pennsylvania for nearly four decades, and our record of outstanding customer service speaks for itself. We have built a reputation for our industry-leading service guarantees and our fair, up-front pricing.

Whether your central heating system is blowing cold air, or you need help with plumbing or commercial refrigeration, our family-owned company is here for you. Contact us today to request a free service estimate or schedule professional repair, maintenance or installation.