Burning or Gas Smell in Millwood, WA

Not every furnace smell is an emergency. But two of them are - and you need to know which.

Rotten-egg or sulfur smell

This is the smell gas utilities add to natural gas so you can detect a leak. Treat it as a gas leak until proven otherwise.

If you smell this:

1. Do not turn any lights or switches on or off. 2. Leave the home immediately. Take everyone with you, including pets. 3. Call your gas utility or 911 from outside or a neighbor's phone. 4. Once you're safe, call CDA Heating & Cooling at (208)916-1956.

Do not re-enter until the utility clears the home. Do not try to find the leak yourself.

Burning smell with headache, nausea, or dizziness

These symptoms can point to carbon monoxide (CO) - an odorless gas produced by incomplete combustion. If anyone in the home feels dizzy, nauseated, or has a sudden headache:

1. Get everyone outside to fresh air immediately. 2. Call 911 if symptoms are present. 3. for a combustion and venting evaluation.

CO has no smell. If your CO detector is going off, treat it the same as a gas smell - get out first, investigate later.

Different smells point to different problems. Here's what's actually happening inside the system.

Dusty or "first heat of the season" smell

This one is usually harmless. Dust accumulates on the heat exchanger and burner assembly during the months the furnace sits idle. When the burners fire up for the first time in fall, that dust burns off. It smells like a hot iron or a dusty radiator.

It should clear within 30–60 minutes. If it doesn't, or if it comes back repeatedly, that's worth investigating.

Burning plastic or electrical smell

This is more serious. Possible causes include:

• Overheating blower motor - the motor runs hot when it's failing, and the insulation on the windings can start to burn.
• Failing capacitor - capacitors store and release electrical charge to start the motor. A failing capacitor can overheat and emit a sharp chemical smell.
• Wiring issue - loose or degraded wiring connections inside the furnace cabinet can arc and burn.
• Foreign object in the system - a toy, piece of insulation, or debris pulled into the return air can land on the heat exchanger and burn.

Don't run the furnace if you smell burning plastic or electrical. Shut it down and call.

Burning oil or metallic smell

This can point to a dry or failing blower motor bearing. As the bearing wears, it generates heat and friction - you'll often hear a grinding or squealing noise alongside the smell. Left alone, the motor seizes and the furnace shuts down on a high-limit fault.

Rotten-egg or sulfur smell

As covered above - treat this as a gas emergency. The most common mechanical causes (once the utility has cleared the home) include:

• Gas valve leak - internal valve seals degrade over time, especially on older units.
• Flue connection leak - exhaust gases can carry sulfur compounds if combustion is incomplete.
• Cracked heat exchanger - allows combustion gases to mix with supply air.

Many homes near the Millwood Historic District and along the Argonne Road corridor were built during construction booms 15 to 20 years ago. Builder-grade furnaces installed during those years are now hitting the end of their expected service life - typically 15 to 20 years for a gas furnace. Heat exchangers on those units are worth a close look.

Millwood's climate adds stress to those aging systems. The area experiences cold, dry winters with temperatures that regularly drop well below freezing - and sharp temperature swings between fall and winter that force furnaces to cycle hard in a short period. That repeated thermal stress accelerates wear on heat exchangers, gas valve seals, and flue connections. A furnace that sat idle all summer and then gets pushed hard through a Spokane-area cold snap is exactly when combustion-related smells tend to surface.

Musty or mildew smell

This isn't a combustion issue - it usually points to mold or biological growth in the ductwork or on the evaporator coil. It's worth addressing, but it's not a safety emergency in the same way.

Before you call - or while you wait - here are checks you can do safely.

Check your air filter. A clogged filter restricts airflow, causes the heat exchanger to overheat, and can produce a burning smell. If the filter is gray and matted, replace it. This is the most common cause of a burning smell that homeowners can fix themselves.

Check your vents and registers. Make sure no furniture, rugs, or drapes are blocking supply or return vents. Blocked airflow causes the same overheating problem as a dirty filter.

Check your CO detectors. If you don't have one near the furnace and on each sleeping level, get them. They're inexpensive and they save lives.

Listen while the furnace runs. A grinding, squealing, or rumbling noise alongside a smell narrows the diagnosis significantly. Note what you hear and tell us when you call.

Do not: - Open the furnace cabinet and start probing components. - Attempt to light a pilot light if you smell gas. - Run the furnace if you smell burning plastic or electrical.