During the year as your HVAC system is used, it may accumulate a fine layer of dust within the heat exchanger, ducts, and on the ignition system. When your furnace turns on for the very first time each season, you may smell a characteristic burning as dust within your system burns off.
If it's your furnace, shut off the power and contact an HVAC technician to have it inspected. While you are waiting, if the smell persists, turn on exhaust fans or crack some windows for ventilation. Plastic and other materials can emit fumes that are not just unpleasant, they can be toxic.
Chemical/Burning Plastic Furnace Smells
If you smell a strange, acrid, burning plastic smell from your furnace, you may have an electrical issue: electrical components, particularly the blower fan, cycle on and off frequently. Over time, these components can wear out and become inefficient or perform poorly.
One primary spot to check: the heating, ventilation and air conditioning (HVAC) ductwork. Checking the HVAC system will help determine if the odor is coming from it or traveling through it from another area. If the odor is coming through the HVAC equipment, you'll need to trace it back through the system.
Electrical systems should be relatively silent. If buzzing, sizzling, or humming noises emanate from your outlets, switches, or electrical panels, these could signal a loose connection or problematic wiring. These sounds can be early signs of electrical fire hazards and should be addressed immediately.
Furnace Smells Like Gas or Rotten Eggs
If you're noticing a gas smell from your furnace, or your furnace room smells like rotten eggs, that smell is probably sulfur. This indicates you have a significant natural gas leak, because gas companies add this odor to alert you.
Since CO has no odor, color or taste, it cannot be detected by our senses. This means that dangerous concentrations of the gas can build up indoors and humans have no way to detect the problem until they become ill.
Phantosmia, which involves smelling phantom smells such as burnt toast, may indicate an underlying medical condition. Researchers have found links between the condition and several medical conditions, including head injuries, brain tumors, schizophrenia, upper respiratory tract infections, and sinusitis.
An olfactory hallucination, known as phantosmia, makes you detect smells that aren't in your environment. The odors you notice in phantosmia are different from person to person and may be foul or pleasant. You may notice the smells in one or both nostrils.
The 'burning plastic or burning rubber' smell is a sign that the copper wires are heating up, and the heat is melting the insulation slowly, bit by bit. This is also a sign that the electrical fire has not started yet, but the copper wires are heating up.
This smell is usually the result of accumulated dust on burners, air ducts or other furnace parts, and it should burn off quickly. If the odor lingers, switch the air filter. If the smell still doesn't go away, contact an HVAC professional to inspect your unit.
The Average Furnace Lifespan
A well-maintained furnace can last at least 15 to 20 years, but completing annual maintenance and being diligent with repairs can extend its life even longer.
While costs can vary, homeowners can typically expect the following range: Standard Blower Motors: These might cost between $400-700, excluding labor. Advanced Multi-Speed or Variable-Speed Motors: These are generally more expensive, with costs ranging between $650-1250, not including labor.
Your base homeowners policy will cover many types of damage to your furnace. An extra endorsement known as Equipment Breakdown Coverage (EBC) will give you additional coverage for certain types of mechanical or electrical failure.
Electric furnace installation tends to be the least expensive, ranging between $3,000 and $7,000, according to HomeAdvisor. Installing a natural gas furnace falls in the range of $3,800 to $10,000, and an oil furnace ranges $6,750 to $10,0000.
For people taking a proactive approach, doing a furnace replacement during the “shoulder seasons” of spring and autumn may offer lower prices, shorter lead times, and a better selection of products and service appointment availability.
Strange Noises
Many healthy furnaces will maintain a consistent whirring sound, which is handy in letting you know that it's in good working order. If you begin to hear strange noises—banging, rattling, irregular hums, groans, rattles, etc. —then that could mean that there's something wrong with the furnace.
While there are many causes, electrical fires can smell like “burning plastic” or “burning rubber” as the plastic insulation surrounding copper wires inside the walls starts to heat and melt, releasing strong unpleasant chemical odors. If the electrical fire progresses, you may begin to smell wood burning as well.
A decomposing mouse smells like propane gas or rotting meat.
A weird smell in a house can come from numerous sources, including appliances, furniture, carpets, fabrics or issues like mold or mildew. Occasionally, odors may be caused by sewer gas, natural gas leaks or animals that have died between walls, in attics or under decks.
Radon gas has no colour, smell or taste and is completely imperceptible to humans, even in high concentrations. Radon occurs naturally in the rocks and soil beneath us, but there is no way of knowing how much is escaping from the ground and entering a building.
Who to call for a strange odor in your home depends on the smell, but home inspectors are a great place to start. They're especially helpful if you don't know the source of the smell and can't narrow it down on your own. A home inspector has expertise in the most common home issues.