The Top 20 Most Common Winter Heating Problems

ac with snow on it

When winter conditions set in across the Columbus, Ohio region, homeowners turn to their heat pumps, boilers, furnaces, and other types of heating systems to stay warm throughout the season. In order to keep your loved ones safe and comfortable all winter long, it’s important that your home’s heating system operate properly, and reliably.

What happens if your furnace, heat pump, boiler, or ductless mini split suffers from a performance problem in the middle of winter? Don’t let a malfunctioning furnace or heating unit put a damper on comfort in your household during the cold months – a heating outage or abnormal operation from your heater doesn’t always mean major system trouble! It’s easy to get stressed by strange noises and unusual errors from your HVAC system, but these things don’t always mean the worst is lurking inside your heating equipment!

Some heating system flaws are really rather easy to fix – and you can fix them fast, too. Buckeye Heating & Cooling shares the top 20 most common heating system problems that are likely to pop up over the winter so you can be aware of what to look out for and know how to get to the bottom of it when you see the signs in your home. With these professional tips from our NATE-certified heating repair technicians, you can restore healthy performance from your heater with just a few quick tricks or know when your furnace, heat pump, or boiler is in need of professional attention.

Take control of your comfort this winter season – learn what heating system problems are most likely to arise and how to correct flawed performance from your furnace, boiler, or heat pump heating system. Below, you’ll find expert troubleshooting steps to guide you through fixing 20 of the most common winter heating system issues on your own! In the event that troubleshooting doesn’t restore strong, reliable heating in your home, Buckeye Heating & Cooling explains what could be troubling your unit requiring a service visit from our team to investigate, identify, and overhaul.

Using Our Heating System Symptoms Guide

When the average homeowner experiences something out of the ordinary in terms of their heating system’s operation or performance, it’s unlikely they’ll know the exact issue at hand – this can make it difficult for homeowners to figure out what possible problems plague their furnace, heat pump, or boiler. You may not know the technical name for the problem or the exact part that’s affected, but what you do know all too well are the symptoms this problem produces – what it sounds like, how it impacts your comfort, and what’s happening with your heating system.

Buckeye Heating & Cooling recognizes that those outside of the HVAC industry search for solutions based on symptoms, not specific terminology – this is why we’ve made our guide to the top 20 most common winter heating system problems incredibly easy for you to navigate and quickly arrive at the information you need! Simply search this guide for the symptoms your heater is forcing you to suffer through, and find out what common issues are likely responsible for this unwanted operation. As always, if you cannot find the information you’re looking for here or you need additional help to solve your heating system troubles, give us a call anytime, day or night, for fast, reliable, heating system repair.

20 Top Heating System Problems That Are Common in Winter

Search through the guide below to find the symptoms your furnace, boiler, or heat pump produces. Under each symptom, you’ll find common causes for the behavior you experience as well as how to troubleshoot each cause on your own. If you run through the troubleshooting steps for all potential causes or suspect a problem that notes professional help is needed, give Buckeye Heating & Cooling a call right away.

1. Your heater doesn’t turn on

When a heating system doesn’t turn on at all, many homeowners panic thinking they’re now stuck without heat. The reality is that it’s a common problem that may have a simple fix. Don’t stress that your furnace or boiler has gone bad, as a minor issue is commonly to blame for this seemingly major heating system problem.

  • Thermostat doesn’t have power. Without power to the thermostat, your heater won’t turn on – the thermostat sends all instructions to your heating equipment, and if it doesn’t have the power it needs to run, your furnace, heat pump, or boiler won’t run either. If the display of your thermostat is blank, a power issue is probable. Remove old batteries and replace them with fresh ones. If your thermostat is wired to your home’s electrical system, open the main panel and make sure the circuit breaker is not tripped – reset it if needed. Remove the thermostat from its wall mount – make sure all wiring connections are tight, adjust with a screwdriver if any connections are loose.
  • Heating equipment doesn’t have power. Your heating system may not run because the equipment itself isn’t properly powered – even though the thermostat signals for it to turn on, it doesn’t have the juice to get the job done. Check the main electrical panel – make sure the circuit breaker is properly set on all circuits powering your HVAC equipment, resetting breakers if needed. Indoor and outdoor units have external power switches, which are usually located either on the exterior of the unit or on the wall nearby – make sure the switch on each unit is flipped to ON.
  • Incorrect thermostat settings in use. Thermostat errors are often to blame for many heating system problems. In order for your heater to run as expected, you need to be sure the thermostat is sending your system the right message. Verify that HEAT mode is selected, not COOL. If you have a programmable thermostat, make sure the schedules are properly set for the time, day, and season so your heater will cycle according to your schedule. Remove the HOLD or VACATION MODE overrides if they have been activated.
  • Equipment panel is loose. Some furnace and air handler models will not run if an access panel is off, ajar, or just not perfectly snug in the closed position. Check the exterior of your indoor unit – feel around on the removable panels to verify all fit firmly in position. If any panels have been removed or replaced without achieving a tight fit, reinstall the panels in the correct position and make sure connections are snug.

2. Little to no airflow from supply vents

If you don’t feel much heat from your vents or no heat at all, don’t worry just yet. Issues with airflow can sometimes be traced to simple problems that can be corrected in a matter of minutes.

  • Register cover louvers are closed. Some covers to supply vents have louvers below the slats, allowing you to open or close these pieces to increase or restrict airflow through the vent. If your register cover has louvers, make sure they are fully moved into the open position. If you are unable to adjust the louvers, they may be stuck – remove the register cover, carefully clean the mechanism and all parts, fully dry the cover, and see if the louvers can now be opened all the way. If so, reinstall the register cover, keeping the louvers fully open. If not, replace the cover with a new one that has working louvers.
  • Filter problems are blocking airflow. A dirty filter will block air from moving through your heating system, which can result in little to no airflow from vents in the home. Check the status of your filter – if it is dirty, remove the existing filter and install a brand new one. Reusable filters should be thoroughly washed and completely dried before reinstalling within your HVAC unit. Double check you are using the right size filter – compare the dimensions printed on the filter’s frame with the filter size information in your heater’s owner’s manual. Double check that the filter is installed correctly – check the airflow indicator arrows printed on the frame and verify that the filter is inserted in the proper direction. Check the filter’s fit in the filter compartment – make sure it is fully inserted and isn’t askew within the filter cabinet as this could block airflow.
  • Ducts have a leak. Leaks in ducts stop the full volume of heated air from reaching your living areas. If your ducts are easily accessible, perform a visual inspection looking for gaps, loose connections, disconnected duct sections, collapsed ducting, and other structural defects. If you have access, minor leak repairs can be made using mastic and you may be able to tighten loose connections as well as reposition fallen ducts. If flex ducting is damaged, you can purchase replacements from your home improvement store, then remove the damaged piece and install the new material in its place. If you are uncomfortable performing these repairs or are unable to access your ducts for assessment or repairs, contact your HVAC company to perform a duct inspection and duct sealing services if leaks are found.
  • Ducts are obstructed. If the duct run has been obstructed, you will not receive the proper airflow volume from the impacted supply vent inside your home. A blockage can happen if ducts have collapsed and disconnected, sustained damage, or something has fallen down through the supply vent. Remove the register cover and look into the duct, checking for items – if you find a fallen item, remove it if possible by reaching your arm down into the duct or carefully inserting a tool to help you dislodge and remove the obstruction. If you are able to access your ducts, inspect for disconnected sections and damage – if a duct run has become disconnected and has fallen, reaffix it and tighten the connection if possible. If you are unable to make this repair yourself or cannot inspect your ducts, contact your HVAC company to do so for you.
  • Blower motor has malfunctioned. The role of the blower assembly is to circulate heated air from the heater through the ducts and into your rooms. If the blower motor malfunctions, it will not turn the blower fan to push air through the duct system. The blower motor can experience a malfunction due to a loose belt, broken belt, faulty belt pully, grime buildup on fan, worn motor bearings, or a faulty motor capacitor. To troubleshoot belt issues, remove the access panel to assess the blower assembly, checking the position and condition of the belt – if the belt is loose, you may be able to tighten it on your own; if the belt is damaged or broken, you may be able to replace it on your own after purchasing a replacement belt. With the blower access panel removed, check the blower assembly for dirty and grime – turn off power to the unit and clean away buildup using a soft cloth and brush as needed; replace the panel and restore power to test your system. Worn bearings will often make a grinding noise as the system runs, and a faulty capacitor may produce a clicking sound though the blower fails to operate – if you hear these sounds or otherwise suspect these problems with your blower, call your HVAC company for repairs.
  • Damper has malfunctioned. A closed damper inside the ductwork may cause an airflow restriction. Automatic or manual damper valves may be installed throughout your duct system to regulate airflow, especially if you have a zoning system installed. Damper louvers can become jammed or stick, keeping the damper in a closed or partially closed orientation which limits airflow through the supply vent. If you have manual dampers and your ducts are accessible, it may be possible to free the jammed louver by moving the level on the exterior of the damper. If your dampers are automatic, their operation is controlled by the thermostat and stuck louvers can be a sign of communication issues between the controls and the damper – call your HVAC company to assess and make repairs or replace the damper if it is damaged.
  • Home needs more return vents. If there are too few return air intake vents in the home, the duct system and HVAC system will not be balanced. Improper pressurization can produce low airflow from supply vents. This issue can only be corrected by installing new return vents and should be performed by your licensed HVAC company.

3. You feel cool air from vents instead of warm air while the heater cycles

When your heater is on, the air that exits your supply vents should be nice and warm after the initial 30 seconds or so, where the system forces out the cool air that was resting in the ducts before heat moves through the system. If you are surprised with cold air from your vents even though the heat is on, these issues could be the reason.

  • Blower fan is incorrectly set. Cold air from your vents when you expect hot can be caused by a simple mistake with the blower settings. If the blower is running constantly, it is easy to mistake its operation for your heater as their operation sounds about the same – when the blower setting is ON, the blower will run all the time and thus send cold air out your vents during those times where your heater is between cycles. Check the blower settings at your thermostat – set the blower to AUTO so that it only runs when your heater does, too.
  • Filter is dirty. When the filter is so dirty that it is fully clogged, it can drastically reduce airflow through your HVAC system – this can cause the system’s internal parts to overheat and turn off for protection. While certain elements of the system may be shut down for safety, the blower could still run, pushing cold air through vents while your heater cools down. Check the filter and replace it if it is dirty. If you suspect your heater has overheated, allow time for it to cool and restart, then check for warm air from the vents.
  • No heating fuel. Most furnaces use natural gas, heating oil, or liquid propane as fuel. If the storage tank’s supply falls below a certain level or becomes empty, no fuel will be sent to the furnace – the system may turn on, but no combustion will take place to generate heat. Damage to gas lines or valves may also prevent a furnace from receiving natural gas supply as it should. For oil or propane systems, check the storage tank levels and refill if needed before operating your furnace again. Inspect gas supply lines and gas valves for damage, and check with your utility provider to see if an outage could be the reason why your furnace is not receiving natural gas.
  • Gas valve is closed. If the valve on the gas supply line leading in to your natural gas furnace is closed, no gas will enter the unit, ignite, and combust to generate heat. The system’s blower can still be operating even though the furnace is not currently burning fuel, which will push cool air through the supply vents. Check the valve on the gas line leading into your furnace – if the handle is parallel to the pipe, the valve is open and gas should flow. If the handle is perpendicular to the pipe, try to open it – if the valve will not open or continues to close, the valve may be faulty and should be replaced by your HVAC company.
  • Ignition is faulty. In order for fuel to combust in a furnace, the ignition must light a flame in the burners. If the ignition is faulty, the burners will not light, gas will not combust to generate heat – your blower may still run even in the absence of a flame, producing cold air from vents. An unlit pilot or dirty ignitor can be corrected on your own if you are comfortable doing so. If not or the ignition needs to be replaced, contact your HVAC company.
  • Significant leaks present in ductwork. Major duct leaks will allow warm air to escape the ducts and cold air from the surrounding areas to infiltrate the duct and mix with the warm air supply, lowering its temperature. Cool air from a supply vent while your heater runs could be the result of significant heat loss through a large duct leak – contact your HVAC company to assess the ducts and make the repair.
  • Condensate line is clogged. Condensing furnaces have condensate drains to remove condensing combustion gases from the system. If the drain is clogged or components are damaged, the pressure switch inside the furnace will open to show that condensation has accumulated in the unit – this prevents proper ignition until the system is properly drained. Check the condensate drain line for clogs, removing them by using a wire cleaning brush or running water through the drain ports. If troubleshooting doesn’t restore drainage or drainage components and pipes have been damaged, contact your HVAC company for repairs.

4. Furnace flame doesn’t light

Once the thermostat tells a gas or oil furnace to start a heating cycle, the fuel valve should open, allowing natural gas or heating oil into the chamber. The ignition should activate, lighting the burners so that fuel can be ignited to generate heat. If the ignition fails in some way, the burners won’t light and fuel won’t ignite – the furnace generates no heat, and the home receives no warmth. Some ignition issues have a quick and easy fix, while others require replacement parts to be installed.

  • Pilot light is extinguished. Furnaces made before about 2010 may have a standing pilot light ignition, where the pilot light is constantly burning within the unit. If the pilot light is extinguished, there will be no flame to ignite fuel once a heating cycle begins. If the pilot is out, follow the owner’s manual instructions to relight it. If the pilot extinguishes again, check for drafts and fix any found in the area. If there are no drafts, a faulty thermocouple or gas regulator may be the problem. Contact your HVAC company to clean and/or replace the thermocouple. A faulty gas regulator will cause fuel supply problems with various gas appliances in the home, and you should contact your utility provider to correct this issue.
  • Dirty electronic ignition. If carbon accumulates on the electronic ignitor, it may prevent the furnace from igniting. This usually produces a repetitive clicking sound that tells you the ignitor isn’t functioning correctly. Cleaning of this component can remove the carbon so it will work properly, but the ignitor is fragile – if you aren’t comfortable cleaning it yourself, contact your HVAC professional to do so.
  • Crack in the hot surface ignitor. If the element in the hot surface ignitor has cracked, it will not light your furnace. This part typically lasts three to five years and needs to be replaced once or more over the life of the furnace. You may do so yourself if you are up to the task or ask your HVAC technician to replace the part for you.
  • Damage to the ignitor. Wear and tear may break down the furnace’s ignitor, requiring replacement of this part. An HVAC technician can use a multimeter to determine if the ignitor is bad and replace the part.
  • Incorrect ignitor installed. If your furnace was recently installed and will not light, the wrong ignitor may have been used which won’t draw the proper voltage for the furnace model. The part will need to be replaced with the correct one by a professional.
  • Faulty limit switch. The limit switch normally turns off the ignitor if the furnace temperature becomes too high. Malfunctions of the switch may stop the furnace from lighting. A dirty air filter can cause the limit switch to shut down a furnace cycle prematurely and keep it from restarting for a period of time – check the filter and change it if dirty, and allow the furnace time to cool off. A damaged limit switch can be professionally replaced.

5. Air filter clogs quicker than normal

You should be replacing your furnace filter on a regular basis, as filters become clogged with pollutants they remove from the air supply. It’s not unusual for filters to require more frequent replacement over the winter months as the system is used more regularly. Outside of increased system use, some system issues can result in a filter filling up sooner than you expect.

  • Blower is ON. Typically, you want the system’s blower to be set on AUTO so it will only run as the furnace cycles. Setting it to ON keeps the blower running 24/7, passing more air through the system which can cause the filter to require replacement sooner than usual. At your thermostat, switch the blower settings from ON to AUTO.
  • Leaks in ducts. Leaks in ductwork can allow more pollutants to mix with the home’s air supply from areas outside the ducts, which are commonly dusty and may have higher particle pollution levels. Duct leaks should be sealed to correct this issue.
  • Dirt around return vents. Air returns to the heating system via return air vents in the house. If the areas near these vents are filled with dirt and contaminants, its more likely these particles will be sucked into the system with returning air and they will clog the filter at a faster rate. Clean return air vent covers and areas surrounding these openings.
  • High indoor air pollution. If you have a high level of certain air pollutants in your home, filters will clog faster. Address sources of indoor air pollution in your home and take steps to reduce or remove them.

6. Thermostat won’t turn on

Your heating system is controlled by the thermostat. If this control doesn’t work and does not turn on, you are left with no means to communicate your heating needs to the furnace, boiler, or heat pump, and your home won’t be heated. Your thermostat may not come on due to:

  • Thermostat was turned off. Occasionally, someone in the home may turn off the thermostat entirely to stop heating instead of adjusting temperatures. The thermostat should always stay on, even when no heating is needed. Check the thermostat settings and make sure the unit itself is ON.
  • Thermostat batteries are dead. Dead batteries will prevent battery-powered thermostats from turning on. Remove current batteries and replace with fresh ones, which should restore power if a battery problem is to blame.
  • Power is disconnected to thermostat. For hardwired thermostats, a disconnection from the power source may stop a thermostat from working. Check the electrical panel and verify the breaker has not tripped – reset if needed.
  • Thermostat wires are loose. Loose wiring connections in the thermostat can interrupt communication between the thermostat and heating system, and make it appear like the thermostat won’t turn on. Remove the faceplate to check electrical connections and use a screwdriver to tighten loose connections before replacing the faceplate.
  • Furnace access panel is loose. Some furnace models will cause the thermostat to shut off if its access panels aren’t properly secured. Check the exterior of the furnace and make sure all panels are firmly in place.
  • Float switch has tripped. If you have a condensing furnace, the float switch that detects high condensate levels may cut power to your thermostat to prevent damage to the system. Check the condensate drain system and make sure condensation is removed appropriately, clearing any clogs you find. Reset the float switch and see if thermostat power is restored.
  • System has overheated. The heating equipment may have overheated if your thermostat shut off mid-cycle. Check the filter and replace if dirty, and check all vents in the home to verify they are open – these two common causes of overheating may be responsible.
  • Thermostat is faulty. If troubleshooting does not cause the thermostat to turn on, there may be a malfunction within the control and it requires replacement. Thermostats should be replaced about every 10 years. Install a new thermostat on your own or call your HVAC technician to do so for you.

7. Heating system doesn’t respond to thermostat adjustments

Your heating system should be responsive when you adjust your thermostat settings. If you adjust the temperature higher or lower and your heating system doesn’t follow this direction, there may be a problem with:

  • Power to heating unit. If the heating equipment’s circuits have tripped breakers, the units will not receive power or work correctly. Reset breakers if tripped. Check that all ON/OFF switches on units have not been accidentally turned OFF – switch to ON if needed.
  • Thermostat lock feature is in use. Some thermostat models have a lock feature that stops adjustments from being made. Check your owner’s manual for steps to unlock the thermostat then try to make your adjustments again and see if your heating system responds.
  • Thermostat is running an AUTO setting. If your thermostat model has the option for automatic operation, this mode may be active which uses programmed setpoints and doesn’t allow for adjustments. Switch the thermostat to HEAT mode to clear this setting and make your adjustments.
  • Wiring problems in thermostat. Dirty terminals and loose connections as well as damage to thermostat wires may prevent the thermostat from communicating adjustments to the heating system. Remove the thermostat faceplate; use compressed air or a soft brush to clean wiring terminals and use a screwdriver to tighten loose connections. If you observe corroded wires, call your HVAC technician to replace wires or your thermostat if needed.
  • Bad thermostat location. If your thermostat isn’t installed in an ideal location, it may not read temperatures correctly which could prevent your adjustments from generating a response from your heating system. If your thermostat is installed by a doorway, in direct sunlight, or otherwise is installed in a less than optimal location, have your HVAC technician relocate it.
  • Thermostat isn’t level. Older thermostats must be level to properly sense room temperatures. If your thermostat’s leveling is askew or the pin connection between the unit and its mounting plate isn’t correct, the thermostat may not register adjustments. Adjust the thermostat’s positioning and reattach the faceplate to establish a clear pin connection.

8. Heat pump won’t keep home heated

If you use a heat pump as your main source of heating, these common problems may prevent the system from providing enough heat inside your home.

  • Using the wrong fan settings. The blower fan should be set to AUTO so that it only cycles when the heat pump does. Using the ON setting forces the blower to run all the time, which could fill your home with cool air between heating cycles. At the thermostat, adjust fan settings to AUTO to correct this issue.
  • Using the wrong thermostat settings. It’s possible the thermostat has been bumped or mistakenly adjusted, switching it to OFF or COOL which will stop the heat pump from running. Check the settings and make sure the thermostat is set to HEAT.
  • Filter is dirty. A dirty air filter prevents strong airflow through the HVAC system which can result in not enough heating indoors. Replace the filter if dirty. Check the filter more frequently during winter as it’s possible you will need to replace it more often during times of heavy system use.
  • Refrigerant leak in the system. If a refrigerant leak causes your heat pump to lose refrigerant, it won’t have enough of the substance to properly move heat and heat your home. This issue must be corrected by a licensed HVAC technician.
  • Reversing valve is stuck. If your heat pump is still cooling your home instead of heating it, the reversing valve may be stuck with prevents your system from reversing to operate in heating mode. Have your HVAC technician inspect the system and replace the valve if it has malfunctioned.
  • Outdoor heat pump is blocked. Items blocking the heat pump can prevent heat transfer so your home doesn’t receive enough heating. Clear away debris such as snow, debris, and vegetation. Remove items stored around the unit.
  • Heat pump has iced up. If the outdoor coil ices over or an abundance of ice develops on the outdoor unit, the heat pump’s operation will be restricted. Normally the system should initiate a defrost cycle on its own but if components such as a temperature sensor or reversing valve are faulty, this cycle may not properly defrost the unit and professional repairs are needed.
  • Starting components are malfunctioning. If your system doesn’t heat your home enough because it won’t turn on, a malfunctioning starting capacitor may stop the motor from getting the power it needs to run. This can make a small clicking sound when a cycle should start, which tells you a new capacitor is needed.
  • Temperatures are too low. Some older heat pump models struggle to supply sufficient heating when outdoor temperatures fall below 40 degrees. Upgrading your heat pump or installing a backup heating system is the best way to solve this issue.

9. You notice cold spots and certain rooms are hard to keep heated

Hot and cold spots along with areas of the home that don’t receive enough heat are often signs of an unbalanced HVAC system where all spaces aren’t receiving the proper amount of heating as the system was designed to deliver. This can be caused by:

  • A dirty filter. Dirty filters restrict airflow so the system has difficulty moving heated air to all parts of the home. Changing the filter if it is clogged can correct this issue.
  • Some vents are closed or blocked. All vents should be opened and unblocked for a balanced HVAC system. Check all vents and make sure they are not blocked by furniture, rugs, and other belongings. If covers have louvers, make sure louvers are open – if louvers are jammed, you can try cleaning the cover or simply replace it.
  • Ducts are leaking. Leaks in ducts allow heat loss and create cold spots. Have your HVAC technician inspect for leaks and perform duct sealing if needed to correct this issue.
  • Ducts are obstructed. An entire run of ductwork can be obstructed by items that have fallen into vents or ducts that have collapsed, causing a lack of heat flowing into the impacted area. Remove vent covers and look into the supply duct for fallen items and remove them if possible. If ducts have collapsed, have the sections replaced by your HVAC company.
  • Dampers are jammed closed. Dampers within the ducts help regulate airflow. If dampers become stuck in a closed position, this will prevent adequate heat from entering the affected area. If you have manual dampers, you can attempt to adjust them using the level on the outside of the duct. Automatic dampers are controlled at the thermostat and an HVAC technician will need to correct any communication issues responsible for dampers staying closed.
  • Ducts aren’t properly insulated. It’s typical for ducts to sit in areas of the house that are quite cold, which can cause great heat loss in warm air circulating to living areas. Adding insulation to ducts can be a DIY project or you can hire a professional to complete this for you.
  • Duct design flaws. If the home’s ducts aren’t properly sized, there are not enough vents, or other duct problems exist, this can be responsible for cold spots. A professional will need to inspect your ducts and implement solutions by repairing the existing duct system or replacing it entirely to prevent cold spots.
  • Thermostat readings are off. If your thermostat is exposed to external heat sources, this can cause the control to misread the room temperature and shut down a cooling cycle prematurely, leading to cold spots. The thermostat will need to be reinstalled in a proper location by a professional.
  • Improper fan speeds. Systems using multi or variable speed blowers may require adjustment so that the blower is able to circulate enough heat to the living areas and maintain balance in the HVAC system. Ask your HVAC technician to make this adjustment if necessary.
  • Heating system is short cycling. If your heating unit shuts down just minutes after starting, this is an issue called short cycling. Short cycling prevents the system from running long enough to generate adequate heat. Short cycling can be caused by dirty filters or closed vents, so troubleshoot those issues first. Improper equipment size is another common cause of short cycling, which can only be corrected by replacing your heating unit.
  • Heating system is too old. If your heater is wearing out, it may not be powerful enough to deliver enough heat to all portions of your home. At this point, replacement is the only solution.
  • Improper equipment size. If your heating unit is too small or too big for the home, cold spots are common. A heater that is too small struggles to produce enough heat while an oversized heater will rapidly heat the home and shut off prematurely, causing cold spots in areas farthest away from the unit. Replacement of the unit is the only solution to these problems.
  • Home is under-insulated. If your home lacks adequate insulation, it could be losing heat which results in cold spot. Installing more insulation in your attic, below floors, and in wall cavities can help your home retain heat and alleviate cold spots.
  • Multi-level home problems. In multi-level homes, downstairs areas often feel much colder than upper levels. Installing a zoning system can balance out this issue, so talk to your HVAC professional about this solution.

10. The heater shuts off soon after starting

A typical furnace, heat pump, or boiler heating cycle lasts 10 to 15 minutes, though cycles may run longer during periods where outdoor temperatures are extremely low. If your heater cycles but shuts down anywhere from a few minutes after starting to about half the length of a normal cycle, this is a sign of heating system problems. Short cycling is the name for this symptom and running your heating system under these conditions will ultimately cause equipment damage as well as energy waste and higher utility bills. Short cycling can be produced by a number of causes, including:

  • Malfunctioning thermostat. Problems such as loose electrical connections, damaged wiring, dirty sensors, improper installation location, or even an unlevel unit for older thermostats with mercury are thermostat issues that can interrupt proper communication with the heating system. To troubleshoot, clean sensors, tighten connections, and make sure the faceplate is properly connected to the wall plate. An HVAC technician can perform recalibration, move your thermostat to an ideal installation spot, or even replace the unit if necessary.
  • Anticipator isn’t calibrated correctly. If you have an old manual thermostat that uses an adjustable heat anticipator, improper calibration can create short cycling. The heat anticipator raises temperatures inside the thermostat using residual heat to shut off a heating cycle – improper calibration could be causing the component to end heating cycles prematurely. This issue may be able to be repaired, but if you’re still using a thermostat with these parts, you’re long overdue for a thermostat upgrade – contact your HVAC company for guidance.
  • System overheats. Restricted airflow is the most common cause of overheating inside your HVAC system. The interior gets too hot and the limit switch detects the high temperatures, then shuts off the system to give your equipment a break and time to cool in order to prevent damage. Check the air filter, replacing it if it is dirty. Make sure all the home’s vents are open and unblocked.
  • Blocked flue pipe. If the flue pipe is blocked, this can also cause the furnace to overheat and shut down early. Inspect the exit point of the flue for obstructions and remove if found, and check the condition of the pipe as damage to the flue may block the exit of combustion gases. If you cannot remove or fix flue pipe obstructions quickly, contact your HVAC company to do so as this issue could also cause carbon monoxide to backup into the home’s living areas.
  • Flame sensor defects. Fuel-burning boilers and furnaces have flame sensors that check for an active flame in burners once the system ignites. Anytime fuel is incoming, the flame sensor checks for a flame to ensure fuel is combusted and that there is no risk of a fuel leak due to non-combusted gas. Soot from combustion can build up on the sensor, preventing it from recognizing the flame when lit. If the flame sensor doesn’t detect a flame, the heating system will be shut down for safety. Carefully cleaning soot from the flame sensor may end this problem. If the flame sensor is faulty, replacement is necessary.
  • Draft inducer motor doesn’t work correctly. If your newer furnace has a draft inducer that expels leftover combustion byproducts in the unit before a new heating cycle starts, malfunctions can stop the furnace. The system’s air pressure switch should sense air movement through the unit’s heat exchanger from the draft inducer, but if air isn’t properly moving through these components, the flue is probably blocked so check for obstructions and remove them. There could also be a malfunction of the pressure switch or the draft inducer motor that will stop these components from running correctly.
  • Heating system is too big. Short cycling is a leading sign of an oversized heating system. Because the system is too big for the home, it produces the necessary amount of heat much faster than the typical heating cycle of a properly sized unit. Since the home reaches warm temperatures faster, the system shuts down earlier than expected – as this problem repeats, it strains components, forces the system to waste energy with more starts and stops, and ultimately causes the heater to breakdown more often than a correctly-sized unit would. Replacing the unit with a correctly sized heater is the only way to fix short cycling caused by this problem.

11. Heater won’t shut off

If it appears that your heating system never stops running, possible causes of this issue include:

  • Using the wrong fan settings. As mentioned before, setting the blower fan to ON allows it to run continuously, even between heating cycles. Because the blower is housed within the indoor unit, its operation is often mistaken for the furnace’s or air handler’s working noise, which causes homeowners to believe their heating systems are running non-stop. Check the fan settings on the thermostat, switching to AUTO so that the blower only runs during a heating cycle.
  • Thermostat malfunction. If your thermostat’s sensors don’t properly detect indoor temperatures or wiring or connection malfunctions disrupt communication between the thermostat and heating equipment, your heater may continuously run simply because it hasn’t received instructions to end the heating cycle. Remove the thermostat faceplate and carefully clean sensors, then tighten any loose wiring connections before reseating the thermostat. It is also possible that the thermostat itself requires replacement to correct these significant communication errors.
  • Malfunctioning limit switch. The limit switch can become stuck inside your heating equipment, which may shut down the furnace due to incorrectly sensing overheating – however, your blower may still continue to run. In this case, the heating system does end the heating cycle, it just sounds like the entire system continues to run due to the blower noise. Your HVAC technician may be able to reset the switch or install a new one if needed.
  • Bad contactor in the compressor. Your heat pump heating system may run continuously due to a bad contactor in the unit’s compressor. This malfunction will provide a constant source of electricity for the heat pump to run continuously rather than properly disconnecting power to components that ends a cycle. A bad contactor can be replaced by a heating repair professional.

12. You’re paying more than usual for heating

A household’s heating bill can increase during the winter for a number of reasons, such as drafts in the home, unseasonably cold outdoor conditions, and problems with the heating system. If your heating unit is consuming more energy than usual and raising the cost to heat your home, these problems may be why:

  • Heat pump can’t perform efficiently in outdoor conditions. Air source heat pumps decline in heating efficiency once outdoor temperatures drop below about 40 degrees – once the temperature falls to 25 degrees or so, the system typically won’t be running efficiently and another source of heating would be more efficient for use in your home. Installing a backup heating system can provide you with a more energy efficient method of heating during these extreme times so your energy bills don’t spike. Your HVAC contractor can install electric resistance heat strips or even a natural gas furnace system to take over when outdoor temperatures are too low for heat pump efficiency. Upgrading your heat pump system to a cold climate heat pump unit can offer better performance when facing low outdoor temperatures.
  • Backup heating system is running when it shouldn’t be. A backup heating system is meant to run only for minor periods of time – the heat pump will always be the primary method of heating the home, and the backup heat source is only there to keep the home comfortable during those extreme periods when the heat pump just cannot run as efficiently (or temporarily during the heat pump’s defrost cycle). If the backup heat system is set to run all the time instead of selectively, your heating bills will be much higher than normal. Check your thermostat settings and verify the correct ones are in use – set the thermostat to HEAT for everyday heating – do not use the EMERGENCY HEAT function, as this will run the backup (aka emergency) heating system.
  • Heating system short cycles. If the heater is constantly short cycling, the furnace, heat pump, or boiler will be consuming far more energy than it will when running heating cycles that are normal in length, due to the increased starts and stops. Components within the system also sustain wear at a faster rate, which causes these parts to draw more energy and operate inefficiently. Troubleshoot sources of short cycling as directed in Section 10 of this guide, and contact your HVAC company if professional help is needed to correct short cycling.
  • Heating system has lost efficiency. As furnaces, heat pumps, and boilers age, they decline in energy efficiency, causing them to operate at a lower energy efficiency rating than what may be listed on the unit’s labeling. Professional repairs may be possible to target specific sources of operating inefficiency, but at this point, replacing the heating unit is the best way to restore energy efficient heating inside your home.
  • Ducts aren’t sufficiently insulated. A home’s ducts often sit in spaces of the home that do not receive heat from the central heating system, and it’s common for these areas to lack in insulation as well, as they don’t typically have much heat they need to retain. Due to contact with cold air, the metal ductwork can lower the temperature of heated air flowing within as air circulates through these ducts on the way to living areas – homeowners then use more heating to make up for the loss and keep spaces comfortable, resulting in higher energy bills. Installing insulation directly around ducts as well as raising insulation levels in the general area where the ducts are installed will be beneficial for lowering heating costs.
  • Ducts are leaking. Openings in ducts allow heated air to exit in spaces where it isn’t meant to go rather than your living areas. The average home loses 20 to 30 percent of heated air this way, forcing homeowners to run their heaters more to make up for the loss – in this case, heating bills are 20 to 30 percent higher than they have to be! Duct sealing can eliminate these losses and lower your energy bills 20 to 30 percent in an instant – contact your HVAC company to schedule this service.
  • Using the wrong thermostat settings. If you use a programmable or smart thermostat, make sure you are using its features as intended or your thermostat settings may be driving up your energy bills. Check programmed schedules, making sure they are in line with heating needs each day – adjust these schedules anytime there is a change in your household’s routine so your thermostat has the most accurate instructions for your needs. Running the blower fan continuously also increases energy bills, as constant energy consumption occurs – keep the fan set to AUTO, not ON.
  • Filter is dirty. If airflow is restricted through your home and heating system due to a dirty filter, the furnace or air handler is going to be using more energy to move air through this blockage and into the home. Filters should be replaced regularly, but it’s often necessary to install new ones more often during the winter as the HVAC system sees more use this time of year. Check your filter each month and replace it anytime you find that the filter is clogged with pollutants.

13. Heating unit produces a burning odor

The only time a burning odor from your furnace or boiler isn’t concerning is in the first hours of system use at the start of the season. This burning smell is simply dust and debris that have settled on internal components burning off after a long period of dormancy. If burning odors continue beyond a few hours on the first day of heating system use or occur at other times during the year, it may be due to:

  • A dirty filter. Dirty filters can trap odors, causing that burning smell to linger longer than it normally would. Remove the old filter and replace it with a fresh one.
  • Faulty wiring. Damaged or faulty wiring within the furnace or air handler can burn off the insulation around the wire and create a burning plastic odor. If you notice this type of burning smell, turn off your heating system and have it inspected and repaired by a professional before further use.
  • Overheated motor. If your furnace overheats, an impacted motor within the unit can generate a burning smell. Troubleshoot causes of airflow blockages and restrictions that commonly cause overheating – replace a dirty filter and make sure all vents are open and clear. Outside of system overheating, a worn bearing within the motor can cause this component to seize and overheat independent of the entire system. Shut off your furnace and have your HVAC technician make repairs before continued use.

14. Water leaks near indoor heating equipment

High efficiency condensing furnaces generate condensation that must be expelled from the system; air handlers for heat pump heating systems may also have condensation to expel. These units are equipped with condensate drip pans and drain lines to capture moisture and carry it outside or to a nearby drain in the home, and conventional furnaces should never produce condensation under normal operating conditions. If you find free water that looks like a leak around your indoor heating equipment, these issues may be why:

  • Condensate drain is clogged. A blockage in the drip pan, drain line, or the drain pump and tube of a condensing furnace model can cause a backup of water that eventually will spill out of the unit to the surrounding areas. Check components of the condensate drain system for clogs, and remove clogs using a wire brush tool or water pressure. Damage to the drain pipe can also create an obstructed path, which acts similar to a clog in the pipe. Check the drain line for damage and replace it if needed – contact your HVAC technician for help if needed.
  • Conventional furnace’s flue pipe is defective. A flue carries combustion byproducts out of a conventional furnace in gas form. If the flue system is designed poorly for use with the furnace or the pipe is not installed correctly, the byproducts may be held within the system long enough to condense into a liquid, which will leak out around the bottom of the furnace. The flue pipe may be longer than it should be, too wide, installed at too much of a slope, or the pipe may be obstructed. You can check for obstructions and remove them at the flue’s exit, but other flue faults will need to be addressed by a professional.
  • Secondary heat exchanger is cracked. Condensing furnaces have a secondary heat exchanger which pulls more energy from combustion gases to utilize for home heating before byproducts exit the furnace. The gases condense in this part of the system, so cracks to this heat exchanger in particular can produce what looks like a water leak from the furnace. A cracked heat exchanger must be replaced by a professional to avoid possible carbon monoxide exposure in the home.
  • Humidifier is leaking. If you have a whole home humidifier installed alongside your HVAC system, this equipment often sits dormant during the winter months as they are more commonly used over the summer. If the humidifier is still in use or if it hasn’t been properly shut down for the season, water you find on the floor around your HVAC equipment may be due to a leak or clog in the humidifier’s water supply line, drain line, or the exterior unit casing.

15. The home’s carbon monoxide detector sounds an alert

Carbon monoxide is naturally produced when fuel combusts in a natural gas furnace or boiler. If the heating system is functioning properly, there shouldn’t be any risk of CO2 exposure inside your living areas – there are certain system issues that can cause carbon monoxide to leak into your home, which should cause the detectors to ring and alert you to its presence. Whenever your carbon monoxide detector goes off, evacuate the home right away and only return once an authority has cleared you to do so.

  • Faulty heating system installation. If the furnace or boiler isn’t properly vented or the flue was not installed correctly, these issues may cause carbon monoxide to make its way into the home. Have your HVAC company inspect your system and correct any installation defects.
  • Heat exchanger is cracked. Once burner flames ignite gas, the byproducts of combustion move in gas form to the heat exchanger of the furnace. The heat exchanger should be entirely sealed and connected to the flue, so there isn’t a possibility of gases like carbon monoxide getting out of the sealed system and mixing with the home’s air supply. A crack in the heat exchanger allows CO2 and other gases to spill out of the system and directly enter the heated air supply which will circulate back to the home’s living areas. Take a look at the heat exchanger by removing the access panel and checking for damage – visible cracks, condensation, and corrosion or rust are signs the heat exchanger may be cracked. Shut off the furnace and have your HVAC company replace the faulty heat exchanger right away.
  • Flue is damaged or obstructed. A clog or blockage of the flue caused by damage to the pipe can prevent gases like carbon monoxide from exiting the heating system to the outdoors. If this occurs, these gases back up into the heater and can mix with the air supply moving through the house. Inspect the flue’s exit point outside your home, which may be on the roof or along a wall – remove any debris or nests and make sure protective vents are in good condition. Remove items or materials in the immediate area of this opening, keeping a minimum of five feet clear surrounding the flue’s exit. If the flue pipe has signs of damage such as rust, corrosion, or visible deformations, contact your HVAC company to make repairs.
  • System is backdrafting. Backdrafting is when the furnace pulls air from the combustion chamber or exhaust, instead of forcing air through these areas and ultimately out the flue. This reversed operation creates the potential for carbon monoxide to infiltrate the home’s air supply. Backdrafting is typically the result of a depressurized HVAC system and duct system – your HVAC technician can investigate this issue and correct its cause.

16. Noisy operation from your heating equipment

Your forced air furnace or heat pump system creates some minimal noise as the equipment runs – you’re probably so used to hearing this slight humming sound that you don’t even notice it! Anytime the system produces a new noise or operation becomes louder than usual, issues may be present in the heater, such as:

  • Dry motor bearings. Motors within furnaces must receive proper lubrication so bearings can operate smoothly. If bearings lack lubrication, motors may produce a harsh grinding noise as they run. Bearings are lubricated during the annual heating system tune up – schedule yours if you haven’t already.
  • Belt problems. If you have an older furnace or air handler with a belt-driven blower fan and motor assembly, issues with the belt’s position can create a squealing sound during heating cycles as well as when the blower fan runs on its own, if set to do so. Remove the access panel to assess the blower assembly’s belt. If there is too much slack, the belt needs to be tightened. If the belt has slipped from the pulleys, it may be necessary to adjust the pulley position. Damage to the belt such as fraying, cracks, or a belt that is broken in half requires a new belt to be installed.
  • Access panel is loose. If one of the metal access panels to your furnace or air handler hasn’t been properly reinstalled after accessing the system’s interior, there may be a rattling noise during a heating cycle. Check all panels, making sure they fit correctly and are snug – remove and reinstall any panels without a good fit.
  • Delayed ignition. If you hear a loud bang from your furnace a short while after a heating cycle starts, delayed ignition is likely – this means the furnace didn’t ignite correctly so gas built up within the chamber and a large amount was ignited all at once. A faulty ignitor may prevent the furnace from lighting correctly. Soot and carbon may clog burners and restrict fuel. If you suspect delayed ignition, turn off your furnace and call your HVAC company for repairs.

17. System breaks down more often this year

If you’ve been making more calls to your HVAC company for repairs this winter than in years past, here are a few things that could be causing this extra hassle and expense:

  • Lack of maintenance. An annual tune up alleviates wear and tear to components so they are less likely to break down. This service also helps detect performance faults that could develop into a major issue and lead to a breakdown. Be sure to schedule your heating system’s tune up each fall, as poor maintenance can lead to more breakdowns.
  • System needs replacement. The average life of a furnace is 15 to 20 years; heat pumps last 10 to 12 years; and boilers can last 15 to 25 years, depending on the type. In the system’s final two years of service, breakdowns typically occur more often than in years prior. An increased need for repair service is a big warning sign that your home is due for heating system replacement.

18. Indoor heating equipment is dirty

If you take a look inside your indoor furnace or air handling unit, do you notice a lot of dust and debris? Extra dirty conditions within your heating equipment can be a sign of these system issues:

  • Dirty filter. Once the filter becomes clogged, it won’t be capable of extracting contaminants from air passing through it. Without this filtration, these particles are able to pass into the chambers of the unit, where airborne debris have opportunities to fall out of suspension and settle on components. This dust and debris can hinder component operation, causing damage and energy waste. Check your filter each month and replace it once its total surface space has become filled with particles.
  • Carbon buildup on the burners. Carbon from the combustion process will gather on the burners over time, and the burner assembly will look dirty if you take a peek at it. Soot along the surfaces of the chamber as well as a yellow flame from burners are other signs that the burners are dirty and need to be cleaned. Burners are professionally cleaned during the furnace’s annual heating system tune up. You may also clean them in between these visits if needed.
  • Cracks in the heat exchanger. If your furnace’s heat exchanger is cracked, you’re likely to notice a large amount of soot along walls and parts inside your unit. You can inspect the heat exchanger for damage, including cracks, rust, and corrosion. Call your HVAC technician to find cracks in the heat exchanger and replace it if needed.

19. The home is too moist throughout the winter

Winter conditions in the Columbus, Ohio area are often dry, leading homeowners to experience dry air issues indoors more so than problems with too much moisture. Windows fogging up and a muggy feeling indoors can be indicators of a high level of moisture in the air. When there is too much moisture in the air, this moisture can cause problems inside your heating system such as mold and mildew growth. Some concerns with the heating system can actually contribute to indoor moisture issues over the winter, including:

  • Not enough ventilation. If your home doesn’t have adequate ventilation installed, your living areas aren’t getting the fresh air they need to move stuffy air out. Installing ventilation products may be necessary, which can be done by your HVAC company.
  • No exhaust fans. Kitchens and bathrooms need to have exhaust fans installed so the moist air produced by daily activities such as cooking, showering, and washing clothing, can be expelled from the house – be sure to use these tools properly, too! If your home’s kitchen and bathrooms do not have working exhaust fans, contact your HVAC company to have these tools installed.
  • Faulty whole home humidifier. Running a whole home humidifier in the winter typically helps homeowners keep moisture levels balanced, but sometimes a humidifier can contribute to moisture problems. A faulty humidistat may force the humidifier to generate more airborne moisture than what is needed, drastically increasing indoor humidity levels.

20. Warning notification appears on the thermostat

If you use a newer model programmable thermostat or smart thermostat, you may see a warning or service notification flash on the screen from time to time. These alerts pop up when the thermostat detects something in need of attention from monitoring the operation of the heating system as well as conditions in the home.

  • Maintenance alert. Some thermostat models flash a notification just to help you remember your heating system’s maintenance needs. Filter change alerts pop up at regular intervals, reminding you to install a new filter.
  • Service alert. If your thermostat detects abnormalities in heating system operation, it may produce a warning notification or send you a service alert. This means there has been a change in household metrics that deviates from normal, which is a possible indicator of a heating system problem. These alerts can tell you it’s time to call a professional for an inspection to learn what the problem is and fix it.

Avoid Common Heating Problems This Winter

Sometimes, problems pop up, impacting your home’s heating system without any warning. However, most of the common heating problems don’t occur suddenly but develop over time. The accumulation of wear and tear along with continued system operation cause minor flaws to grow into big problems, which may or may not be repairable. The best way to avoid surprising situations like this is to make sure your furnace, heat pump, or boiler receives its professional heating tune up each year.

For professional care to maintain your heater or heating repairs to fix a faulty furnace, heat pump, or boiler, turn to the NATE-certified HVAC technicians of Buckeye Heating & Cooling. Contact our team today to schedule service.

Subscribe for Savings and Tips in Your Email!