Burning plastic fumes can be a nuisance in a home even when they’re subtle. Worse still, they can be a sign of an impending electrical hazard or appliance breakdown, so you must act quickly. But to do so, you need to pinpoint the origin of the smell, which can be tricky because there are several potential causes.
The smell of burning plastic in a house can be caused by a water heater, wood burner, the A/C, and other household appliances. It can also be due to faulty wiring. Depending on the source, the magnitude of the smell may vary, and you might need a repair technician’s services.
In the rest of this post, we’ll be discussing in detail the above causes of burning plastic smell in a house to help you address the issue. Ready? Let’s dive right in!
The Water Heater
The water heater is one of the most common causes of burning plastic smells in homes. If yours is causing this kind of smell, first cut off the power at the circuit breaker before you begin tracing the source of the problem. This way, you’ll avoid potential electrical hazards.
Several factors can cause the smell of burning plastic in a heater.
- The thermostat, which is usually mounted outside the heater. Sometimes, the thermostat’s electrical contacts overheat, causing the plastic parts near them to burn, hence the smell.
- The insulation. If it’s old or poorly packed, it can allow some parts of the wiring to come into direct contact with each other or with heating elements. When this happens, the insulation overheats, hence the smell of burning plastic.
In either case, you’ll want to get your heater checked by a trained technician unless you’re handy with electrical appliances.
Should you choose the DIY route, start by identifying the cause of the smell from the two factors we identified earlier. If the thermostat’s contacts are the culprit, simply replace them. As for the insulation, you can either replace it or adjust the plastic parts’ position, depending on the cause of the problem.
A Wood Burning Stove
Usually, when the smell of burning plastic comes from your wood burner, it’s either you burned plastics (often in the form of junk mail), or the appliance is new. If the smell is due to the latter, it’s because the stove’s paint is yet to cure.
Concerning the wood stoves, curing refers to when some of the paint’s solvents begin to evaporate the first time the appliance is heated to extreme temperatures. This process changes the chemical structure of some of the elements in the paint, leaving the stove with the desired finish as anticipated by manufacturers. Unfortunately, a paint smell (often confused with the smell of burning plastic) is one of the by-products of curing.
But there’s some good news: if curing is the cause of the smell, it’ll go away after you use the stove three to 4 times at high temperatures.
If the smell persists beyond that, chances are something is burning off further up the flue system, so you might want to have that checked. While you’re at it, check the kind of wood you’re burning. If it’s treated, switch to untreated wood because the chemicals in the former can also release a chemical smell that resembles that of burning plastic.
The Air Conditioning System
The smell of burning plastic in an AC often means a bigger problem that needs to be checked out by a technician, and is usually due to one or a combination of the following issues:
- Something is burning in another part of your home, and the AC is simply re-circulating the stench.
- Your heater is burning off accumulated dust.
- Some parts of your AC are overheating.
Whenever you notice the smell (especially if it’s the first time), cut off the AC’s power, and call the fire department, and with your safety guaranteed, let’s take a deeper look at some of the reasons why the smell could be lingering.
- An overheating motor in your AC. Inside your AC, there’s usually a fan that circulates air throughout your interior space. With continued use, the fan motor’s bearings may wear out and subsequently cause the motor to overheat. When this happens, any plastic parts near it will give off a burning smell.
- A bad capacitor. Without getting too technical, the capacitor is a part of your AC that helps keep the motor running, and when it isn’t functioning as efficiently as it should for whatever reason, the motor overheats, resulting in a burning smell.
- Another electrical issue apart from the motor and the capacitor. When the smell isn’t due to either of these two reasons, it could be that a malfunction in one of the parts of your AC’s circuit system is causing the motor or another component to overheat.
You’ll need an AC repair technician to diagnose and fix the problem in any of these cases.
Faulty Electrical Wiring
When the smell of burning plastic emanates from electrical wiring, short circuits are usually the culprit. In simple terms, a short circuit facilitates an abnormal connection between two electric circuit nodes that are meant to sustain different voltages. This can cause a variety of issues that include overheating, circuit damage, fire, or even an explosion.
So when you’re smelling burning plastic in your wiring, chances are the insulation is melting due to excess heat. Usually, the smell is pungent, so it won’t be hard to notice.
However, what will be hard is locating the source of the problem because the short circuit can be anywhere along the length of wiring, which is usually built into a wall. Perhaps the only situation where you might be lucky enough to locate it easily is when the short circuit is in a specific outlet.
That’s why you’d be better off (and much safer) leaving the diagnosis and the fixing to the experts. Speaking of which, you’ll want to call an electrician the moment you notice any burning smell in your wiring. By then, the situation will be critical because electrical wiring usually heats up for years before it starts to melt or set ablaze other materials around it.
Other Household Appliances
The HVAC system, water heater, and wood-burning stove aside, two other household appliances may cause your home to smell like burning plastic. These include self-cleaning ovens and dishwashers.
With self-cleaning ovens, the cleaning mechanism is often the cause of the smell, and most of the time, there’s no need for concern. Most people don’t know it, but ovens with self-cleaning functionality usually clean by burning off any residues you leave behind. If there’s any plastic in the residue, it’ll smell as it burns.
As for the dishwasher, the plastic smell occurs when utensils made of this material fall to the bottom and come into contact with the appliance’s heating element.
As you have read, the smell of burning plastic can be due to several reasons, and pinpointing the cause and addressing it may call for a trained eye (especially when electricity is involved).
But fixing the root cause is just one part of the equation because the smell might still linger.
To get rid of it, open your windows and switch on the fans (not A / C, otherwise the odor might enter the system) to help dissipate the smell. Next, simply clean your house like you usually do, only with baking soda or vinegar added to your routine. These two are effective odor removers and can be used in virtually all parts of your home, from carpets and floors to curtains.