Troubleshooting Common Furnace Issues

Every home has its quirks, especially when it comes to old houses with aging infrastructure. These issues can be frustrating and costly, but they are also common problems that can often be fixed quickly and easily by someone with the right knowledge and tools. Let’s face it—not every day is a good day. There will come a time when you look forward to crawling into bed at night and dreading the thought of getting up in the morning. The same goes for your home’s furnace. From breaking air filters to frozen CO sensors, there are plenty of things that can go wrong with your heating system. Fortunately, most of these issues are preventable or can be caught early enough before any serious damage occurs. Here are some common problems that may plague your furnace and their solutions so you can get back to enjoying your home again sooner rather than later!

A Ductless Furnace May Be the Problem

Although a ductless furnace is a great addition to any home, some issues can come along with it. One of the most common is the temperature difference between the hot air being vented and the surrounding air inside the home. The solution to this problem is very simple: install a vent that leads the hot air out of the house and uses the outside air to bring in fresh air indoors. You will have a single temperature inside and outside, and your utility bills will be lower as well! The other potential problem with a ductless furnace is that the temperature of the air being blown through the vents is lower than the temperature you selected on the thermostat. This is often due to the position of the thermostat and where the air is being vented. If you’re not satisfied with the temperature of your vents, you can use inline temperature control to keep the air where you want it.

Your Air Conditioning Unit Is Failing

If your AC stops working, many things could be causing it. If your AC is more than 10 years old, you may want to consider replacing it with a new one. However, if your AC is relatively new, you may just need to change out an inefficient filter. A clogged filter will reduce airflow and cause your AC to overheat and break. You may also need to remove any debris that built up around the unit. If humidity is high in your area, you may need to service the condensate drip leg. This can cause water to leak inside your AC, causing damage. You may need to replace the gasket or purchase a new unit. If the outside unit is warm, the condenser fan is not working. A technician may need to replace the capacitor or contractor to fix the problem. If you hear loud buzzing noises or a clicking sound, this could be a sign that a freon leak is occurring. Your AC could stop working if the leak is significant.

Condensation Can Lead to Rot and Smells

Condensation is a common problem, especially in areas with low humidity. It happens when warm, indoor air comes in contact with a cooler surface and cools down to the temperature of the cooler surface, causing water droplets (condensation) to form. If your house has an unfinished basement or crawlspace, the humid indoor air will eventually come into contact with the cooler foundation walls and condense. This moisture will then drip down the walls into a puddle and collect in a tray. This is a good thing, as it is redirecting the water into a place where it can evaporate. The problem arises when that water doesn’t evaporate. It sits there, rotting the wood around it. This can cause your home to have a musty smell, which is often confused with a water leak. If you notice a musty smell in your home, look for signs of condensation.

Your Condenser Or Evap Coil Is Frozen

In areas where you see frequent freezing temperatures, you’ll want to take precautions to protect your indoor furnace components. There are a few different ways to do this. First, make sure your indoor AC unit is placed on a concrete floor. Second, you should use a seal around your outside AC unit. You can also use insulation on the inside of your AC unit. If you live in an area that sees freezing temperatures, you’re at risk of your indoor AC unit freezing. Freezing temperatures can cause your indoor condenser or evaporator coils to ice up. Ice can block airflow, reduce efficiency, and shut down your system. If your AC freezes, call a professional. The frozen AC unit will need to be defrosted before it can function again. Do not try to manually thaw out your AC; you could get injured.

Your Heat Exchanger Is Frozen

You can typically find your heat exchanger in the furnace room or basement. It is what transfers the heat from the furnace’s combustion process into your home’s ductwork. This is a common issue in areas where you see freezing temperatures. You can use a few different methods to protect your heat exchanger from freezing. Make sure your furnace room has the proper insulation. Shut off the furnace whenever the outside temperature drops below freezing. Cover the heat exchanger with a protective blanket. If you live in a cold climate, you may want to consider purchasing a condensing furnace. These furnaces use a heat exchanger that’s designed to freeze less often than traditional heat exchangers.


Many things can go wrong with your furnace, but these issues are often preventable. Make sure your air filter is clean and be sure to regularly change it out because the filter is your first line of defense against dust, pollen, and debris. Have your furnace and air conditioning unit checked every year to make sure they’re running properly. Have a professional come out to inspect them and make sure they’re running efficiently and effectively. With a little maintenance, you can avoid many of the common issues that plague your furnace.