Under normal operating conditions, your furnace should not create any strange odors. If you can smell something strange, it may be tempting to ignore it until it goes away. But, there are some odors that are warning signs that shouldn’t be ignored. To protect yourself, your family, and your home, consider these six strange odors as warnings.
A Burning Odor
Before we begin, let’s take a moment to talk about that initial burning odor that you may smell when you fire up the furnace for the first time in months. This is not a serious problem. What you can smell is the coating of dust that’s accumulated on the surface during the summer months. After a short time, this burning odor should dissipate, and if it doesn’t, it’s time to change the furnace filters. If the smell is still lingering, contact your local HVAC specialist and ask about cleaning and essential maintenance.
6 Potentially Dangerous Furnace Odors
Let’s take a look at six potentially dangerous furnace odors that you should not ignore:
1. An Electrical Burning Odor
This is a very different odor than the dusty burning odor that you may experience when you start up the furnace after a long period of inactivity. This burning smell has a distinctive odor, like an overheated motor or a burning electrical wire. This could indicate the impending failure of a blower motor that may be caused by worn bearings. A blower motor can also overheat when too much voltage is used, and this could melt any attached wires. Any burning in the home should be treated as serious. There is a risk of electrocution if you try to fix the problem with DIY skills. Turn off the system with the thermostat and call your local HVAC specialist to investigate and fix the problem.
2. A Strong Chemical Smell
A strong formaldehyde chemical smell may be a sign that the heat exchanger has cracked. This is a very serious problem; the crack can release poisonous carbon monoxide gas, which is known as “the silent killer” for good reason. This gas can circulate throughout the home quickly when the heating system is running. For this reason, it’s important to install carbon monoxide detectors near the furnace and throughout the home. It’s also important to note that a cracked heat exchanger can release flames that cause house fires that are fatal for many people every year. Detecting a heat exchanger crack can be tricky because the crack can close when the heat is turned off. If you suspect that you have a cracked heat exchanger, shut off the system and contact your local heating and specialist.
3. A Rotten Egg Odor
If you have a gas furnace, you may not be aware that the gas you use doesn’t have a discernible odor. This is dangerous because it’s hard to detect a gas leak that could lead to an explosion or house fire. For this reason, natural gas suppliers add sulfur to your gas to make a leak stink like you have rotten eggs in your home. This odor cannot be ignored or confused with anything else, and it is a sure sign that you need to shut off the gas and get everyone out. The next step is to call 911 and the local gas company to detect and fix the leak.
4. A Smoky Smell
If the chimneys are blocked or obstructed, this can cause the furnace smoke to come through the ductwork and enter your home. When we breathe smoke particles, there is a risk of lung damage, and certain other health issues can be triggered. Smoke can also permeate the soft furnishings causing a lingering odor that can be hard to remove without professional cleaning services. The best way to prevent this problem is to get the chimney inspected and cleaned before the heating season begins. So, if you can smell a strong smoky odor, shut off the furnace and contact your local HVAC specialist.
5. A Musty Odor
A damp and musty odor emanating from the ductwork indicates a specific problem in the system. These areas are a prime location for the growth of mold and bacteria. They thrive on moisture that may have accumulated in the ductwork, and breathing bacteria and mold spores are bad for our health. When the system is running, the air will pass through the ductwork and carry these pollutants throughout the home. If you smell this odor, contact your local heating and cooling specialist to check the ductwork. An inspection, servicing, and cleaning may fix the problem. If the ductwork is in very poor shape, it may be more economical to replace it entirely.
6. A Car Exhaust Smell
This smell is usually a sign that there is some kind of venting issue that needs to be solved. The furnace has a vent pipe that moves the gasses that are created during combustion outdoors where they can do no home. Even if you have a high-efficiency model, it will still have a PVC vent pipe to remove the trace gasses. The exterior of the vent pipe can be obstructed with a variety of materials, including ice, snow, bird nests, leaves, and other debris. Fixing this issue should be a priority to prevent carbon monoxide and other toxic gasses from coming back into your home.
In Conclusion
If you can smell strange odors or other aberrant behaviors in your furnace, it should be taken seriously. Under normal operating conditions, the furnace and air conditioner system should not generate strange odors or weird noises. These phenomena should be treated as an early warning system to take further action to fix the problem. The type of odor that you can smell may give you some helpful clues that you can share with the HVAC technician. Most of the potential problems that we’ve shown in this article are beyond the scope of basic DIY skills and tools. To protect yourself, your family, and home, it’s a better idea to contact your local HVAC specialist for expert help and advice.