The first truly cold night in Lithia Springs often arrives out of nowhere, and that is usually when furnaces pick the worst time to act up. One day the house feels fine, and the next morning you wake up and can see your breath in the hallway while the thermostat keeps climbing but never quite reaches the number you set. That sudden drop in temperature does not just make you uncomfortable, it pushes your heating system harder than it has worked all year.
In our area, we get long stretches of mild weather, then a fast-moving cold front that drags temperatures down into the 20s. Many homeowners assume that if their furnace came on last winter, it will be ready for whatever this year brings. What we see in the field tells a different story. A furnace that coasts along in mild weather can start to show its weaknesses the moment a real cold snap hits Lithia Springs, Douglasville, or Mableton.
At Ronald Smith Heating & Air, we have been working on heating systems in this community since 1981, and our NATE certified technicians know what tends to fail on the first hard freeze. Every year, the phones light up with no-heat calls that trace back to issues that could have been prevented or at least softened with a little preparation. In this guide, we want to share what we have learned about how cold snaps strain furnaces and how you can get your system ready before temperatures drop.
How A Cold Snap Strains Your Furnace In Lithia Springs
A cold snap changes the way your furnace has to work. On a typical cool evening in Lithia Springs, the temperature difference between indoors and outdoors might be 15 or 20 degrees. When a strong front moves through and the outside temperature falls into the 20s or teens, that difference can double. The bigger the temperature gap, the harder your furnace has to run to keep indoor conditions steady.
Inside the system, that extra demand shows up as longer run times and shorter rests between heating cycles. The burners or heating elements stay on longer, the blower motor spins for extended periods, and the metal in the heat exchanger heats up and cools down more dramatically. All of this creates more expansion and contraction inside the furnace cabinet, which slowly wears on components that already have a few seasons behind them.
In our part of Georgia, many homes and light commercial spaces were built with the expectation of relatively mild winters. That often means ductwork routed through attics or crawlspaces that are not fully conditioned, and equipment sized to handle most winter days but not long stretches of extreme cold. When a cold snap hits Lithia Springs, that combination of greater temperature difference and heat loss through ducts and building leaks can push a borderline system to its limits.
We also see the impact of everyday habits. During a mild spell, you might set the thermostat a little lower and not notice if the furnace takes a while to recover. During a cold snap, most people dial the temperature up and expect a quick response. That increased thermostat setting adds even more load to the system, which is already working against a bigger temperature gap. The result is a furnace that may seem fine in November, then struggles or fails during a sharp freeze in January.
Common Furnace Weak Spots Cold Snaps Tend To Expose
Cold snaps often bring out problems that have been quietly developing all year. One of the most common weak spots is airflow. A dirty filter, closed supply vents, or blocked return grilles may not cause an immediate breakdown when the furnace only runs for short cycles. When the system runs almost continuously, restricted airflow can cause the heat exchanger to get hotter than it should. The safety limit switch senses that heat and shuts the burners off to protect the equipment, which leaves you with lukewarm air and frequent on and off cycling.
Ignition and flame sensing issues also show up more often during extreme cold. Many modern furnaces use hot surface igniters and flame sensors that need to be clean and properly positioned. Over time, igniters can weaken and sensors can pick up a thin layer of oxidation. In mild weather, the furnace might still light after a few tries, and you never notice. During a cold snap, when the system needs to start reliably over and over, those same marginal parts can finally refuse to cooperate, leaving the furnace locked out and the house cooling quickly.
Older systems or units that were just barely sized for the home also reveal their limits. On a 40 degree night, a furnace like that may run a bit longer but eventually reach the set temperature. On a 20 degree night with wind, it might run nearly nonstop and still struggle to maintain comfort, especially in rooms with more exterior walls or poor insulation. Homeowners often notice cold bedrooms at the far end of the duct system or bonus rooms over garages that never feel warm enough during these events.
Ductwork and building shell issues are another hidden weak spot. Leaky ducts in an unconditioned attic can dump warm air into a space you do not occupy, which only becomes obvious when the furnace is pushing a lot of air for long periods. Gaps around doors and windows, or poorly insulated walls, allow more heat to escape when the temperature drops fast. The furnace gets blamed, but the real problem is often a mix of equipment and building conditions that only matter during the coldest weather.
Simple Checks You Can Do Before Temperatures Drop
There are several simple, safe checks you can do yourself before the next cold snap to reduce the chance of waking up to a cold house. Start with the air filter. Pull the filter out and hold it up to a light. If you can barely see light through the material or you see heavy dust buildup, replace it with the correct size and type. A clean filter allows proper airflow across the heat exchanger, which helps the furnace run at the right temperature during long heating cycles.
Next, walk through your home and make sure all supply vents and return grilles are open and not blocked by furniture, rugs, or curtains. Closed vents can seem like a good way to push more heat to other rooms, but they actually increase pressure in the duct system. That higher pressure can reduce airflow and make the furnace run hotter than intended, especially when it rarely shuts off during a cold snap. Keeping vents open and clear helps the system move air the way it was designed.
Take a look at your thermostat as well. Make sure it is set to heat and that the temperature you have chosen makes sense for very cold weather. If you like to set back the temperature at night, consider a smaller setback, for example, 3 to 5 degrees instead of 10 or more. Deep setbacks require the furnace to work much harder in the early morning hours, which are often the coldest of the day in Lithia Springs, and that extra strain can reveal issues with ignition or airflow.
When the furnace first starts running for longer periods, pay attention to how it behaves. Listen for unusual noises like grinding, squealing, or loud bangs, which can indicate motor, bearing, or ignition problems. Watch to see if the system starts and stops every few minutes, which is called short cycling, or if it blows cool air after only a short burst of heat. These are early signs that something is not quite right. If you notice them before or during a cold snap, it is worth having a professional look at the system rather than waiting for a full breakdown.
What A Professional Furnace Tune-Up Covers That A Checklist Cannot
While homeowner checks are helpful, there is a lot that only a trained technician can safely and accurately evaluate before a cold snap. During a professional tune-up, our technicians go beyond cleaning and look closely at how the system operates under load. For a gas furnace, that includes checking gas pressure, verifying ignition sequences, and confirming that the burners are producing a clean, stable flame. For all furnaces, we inspect the heat exchanger area for signs of cracking or corrosion that might not be visible without the right tools and lighting.
We also test the safety controls that protect your home and equipment. This can include the high limit switch that shuts down the burners if the furnace gets too hot, pressure switches that confirm proper venting, and rollout switches near the burners. During an inspection, our NATE certified technicians will often measure temperature rise, which is the difference between the air going into the furnace and the air coming out. If that number is out of range, it can point to problems like restricted airflow or incorrect gas input, both of which become more serious during an extended cold snap.
Electrical checks are another part of a thorough tune-up. Our team inspects and tightens electrical connections, tests capacitors that help blower motors start and run, and evaluates the condition of control boards and relays. A weak capacitor or loose connection might not cause noticeable symptoms when the system only runs occasionally. When the furnace runs for hours during a cold snap, those minor issues can quickly turn into a no-heat situation.
As a Carrier Factory Authorized Dealer, we follow manufacturer guidelines on inspection and maintenance, and we have access to quality products and parts when a worn component needs to be replaced before it fails under stress. Over the years, serving Lithia Springs, Douglasville, Mableton, and nearby communities, we have seen how a pre-season tune-up can catch the small issues that become big problems during the first freeze. Sharing that perspective is why we encourage customers to schedule maintenance before the forecast calls for several nights of hard cold.
Signs Your Furnace May Not Keep Up With The Next Cold Snap
Even before the coldest weather hits, your furnace may already be telling you it will struggle. One clear sign is a home that never quite reaches the thermostat setting on colder evenings, even though the furnace seems to run a lot. You might notice that certain rooms stay chilly or that the system shuts off only to turn back on a short time later. This can indicate a mix of issues, such as duct leaks in unconditioned spaces, insufficient return air, or a system that is right on the edge of its capacity.
Short cycling is another warning sign. If the furnace starts, runs for only a few minutes, then shuts off and repeats that pattern often, something is not working properly. Possible causes include overheating from restricted airflow, a malfunctioning limit switch, or issues with the control board. During a cold snap, short cycling not only fails to heat the home effectively, it also puts more wear on the ignition system and blower motor, which can lead to complete failure.
Pay attention to your utility bills as well. A noticeable jump in gas or electric use during colder weather, compared with similar conditions last year, can signal that the system is working harder than it should. That extra energy draw may come from a failing blower motor, dirty indoor coil on a hybrid system, duct leaks, or a furnace that is simply operating at reduced efficiency because it has not been maintained.
Noise and odor changes are also meaningful. A furnace that rattles, booms when it starts, or squeals from the blower compartment is not just an annoyance, it is a sign of mechanical stress. Musty or metallic smells when the unit runs are another clue that dust, debris, or overheated components are present. From what we have seen in the field, these problems rarely fix themselves. They tend to worsen with each cold snap, and the coldest nights in Lithia Springs are often when weakened equipment finally gives up.
Balancing Comfort And Energy Use During A Cold Snap
When the temperature drops fast, it is natural to be tempted to crank the thermostat up several degrees. Each extra degree of indoor temperature, however, increases the amount of heat your furnace must deliver and lengthens how long it has to run. During a cold snap, those longer run times are already unavoidable, so setting a very high temperature can push both your system and your energy bill harder than necessary.
A more balanced strategy is to choose a comfortable but reasonable setpoint and avoid large, frequent changes. For many households, that might mean holding the thermostat around the upper 60s to low 70s during the time you are home and awake, and only lowering it a few degrees at night. Smaller setbacks mean the furnace does not have to recover from a big temperature drop during the coldest hours, which reduces strain on components like igniters, motors, and heat exchangers.
Supporting steps around the home can make these moderate settings feel more comfortable. Closing curtains at night to reduce heat loss through windows, sealing obvious drafts around doors, and making sure interior doors to seldom used rooms are positioned thoughtfully can help. Just be careful not to close off so many areas that you disrupt airflow in the duct system. The goal is to help the furnace by reducing unnecessary heat loss, not to choke off air movement.
For some homes, a cold snap makes it clear that the existing equipment is not a good match for the space or that operating costs in extreme weather feel too high. In those cases, higher efficiency furnaces or hybrid heating applications, which combine a heat pump with a gas furnace, can offer better performance and more stable operating costs during future cold snaps. At Ronald Smith Heating & Air, we work with customers to evaluate these options so any upgrade fits the home and the way the family uses it, rather than taking a one size fits all approach.
When To Call A Furnace Professional During A Cold Snap
There is a point where it is safer and more cost effective to stop troubleshooting on your own and call a professional. If the furnace stops producing heat altogether, blows only cold air, or repeatedly shuts off and flashes an error code, it is time to bring in a trained technician. The same is true if you notice burning or electrical smells, loud banging noises, or see signs of flame rollout in a gas furnace, such as scorch marks around the burner area. These conditions can signal serious safety issues or developing damage to critical components.
Gas valves, ignition systems, and high voltage electrical circuits require proper tools and training to diagnose correctly. Continuing to reset the system or cycle power without understanding the underlying problem can sometimes make things worse. For example, if a limit switch is tripping because of restricted airflow, forcing the furnace to run repeatedly can overheat the heat exchanger, shortening its life. Addressing the root cause quickly is always better than pushing the system through a cold snap in a compromised state.
We also recommend calling for service if you notice the warning signs described earlier, such as persistent short cycling, noisy operation, or large comfort gaps between rooms, even if the furnace is still running. During a cold snap in Lithia Springs, service demand often spikes because many systems fail at the same time. Reaching out at the first sign of trouble can often mean a faster response and a simpler fix than waiting until the furnace fails completely on the coldest night of the year.
As a family owned company serving this area since 1981, Ronald Smith Heating & Air provides maintenance, repairs, and new installations for both residential and commercial customers, and our team’s customer care has been recognized with honors such as the Carrier President’s Award. If repair or replacement becomes necessary during or after a cold snap, we can also discuss special financing options that help make those unexpected costs more manageable, so comfort and safety are not delayed because of budget concerns.
Stay Ready For The Next Cold Snap In Lithia Springs
Cold snaps in Lithia Springs put every part of your heating system to the test, from airflow and ductwork to ignition components and safety controls. With a better understanding of how that stress works, a few simple checks at home, and timely professional maintenance, you can reduce the odds of waking up to a cold house just when your family needs heat the most. Paying attention to early warning signs gives you the chance to address problems on your schedule instead of the weather’s.
If your furnace has not been inspected in the last year, or if you have already noticed any of the symptoms we described, scheduling a tune-up or diagnostic visit before the next hard freeze can make a real difference. At Ronald Smith Heating & Air, we treat our customers like family and draw on more than four decades of local experience to keep homes and businesses in Lithia Springs, Douglasville, Mableton, and nearby communities warm when the temperature drops. To plan ahead for the next cold snap or get help with a current furnace concern, contact us today.