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Two Kenwood portable electric heaters seemed to perform well ... until they didn't. A failed control, signs of burning and over heating, and concerns for fire safety led us to put these two heaters out with the trash (C) Daniel Friedman at InspectApedia.comPortable Electric Heaters
Failures, Fire-Hazards, Safety

Portable electric heaters: examples of failures, dangers of combustible plastic, failure of heater controls and plastic parts.

This article series describes the types of residential electric heating systems and their inspection, diagnosis & repair.

We describe each type of electric heat used in buildings and provide links to further and more detailed electric heat diagnosis & repair articles for each heater type.

InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

- Daniel Friedman, Publisher/Editor/Author - See WHO ARE WE?

Portable Electric Heater Overheat & Risk of Fire

Photo of the discontinued-use electric heater next to a milkhouse heater fro Power Gear (C) Daniel Friedman at Inspectapedia.comHere we describe and illustrate overheated, damaged plastic parts in portable electric heaters. As Dr. Aronstein [cited below] points out, combustible plastic parts used in many modern appliances are a serious fire hazard.

Photo: The now-trashed electric heater that we disassembled, examined, and whose troubles we document on this page is the white one in the photo at left.

[Click to enlarge any image]

Unlike Aronstein, who is not afraid to let an electrical device catch fire during testing by an expert (see Electro-Kindling cited below), after seeing signs of serious overheating at the two heaters shown at the top of this page, rather than plug them in and wait to see them catch fire, we put these heaters out with the trash.

Two of the heaters shown at left in our photo and in use in northern Minnesota were replaced with what we believe to be a safer portable electric heater alternative: heaters that use all-metal parts, such as milk-house heaters and other all-metal heaters illustrated on this page.

There are several all-metal or nearly-all-metal portable electric heater types and brands as we illustrate and discuss below. In our OPINION and citing research in this article, portable heaters that avoid use of plastic parts, certainly combustible plastic parts, are safer than others.

First signs of trouble at an electric heater

The portable electric heater whose overheating, demise, and disassembly are illustrated here, had been in intermittent use in northern Minnesota for about six years.

Portable electric heater controls (C) Daniel Friedman at InspectApedia.com ... Brown burning plastic and metal parts on a portable electric heater (C) Daniel Friedman at InspectApedia.com

Signs of trouble inside the heater, found by disassembly included

Fragile plastic heater parts that held controls apart were heat-damaged, brittle, and disintegrated easily (C) Daniel Friedman at InspectApedia.com

Above: plastic cast parts integral with the shell of this heater and intended to hold controls in place were so deteriorated by heat that they disintegrated on the least disturbance.

Overheat damage to portable electric heater parts may cause fire hazard (C) Daniel Friedman at InspectApedia.com ... Overheat damage to portable electric heater parts may cause fire hazard (C) Daniel Friedman at InspectApedia.com ...

and a burned heat on-off-range control toggle switch (below)

Damaged by heat, this control switch was cracked and brown at its connectors (C) Daniel Friedman at InspectApedia.com ... Heat damaged control switch from portable electric heater (C) Daniel Friedman at Inspectapedia.com

...

Damaged by heat, this control switch was cracked and brown at its connectors (C) Daniel Friedman at InspectApedia.com

We noted that the heater's internal electrical wires did not show signs of overheating or damage. The trouble centered on plastic parts.

Types of electric heater failures that may lead to unsafe conditions

Data tag for the heater illustrated above:

Portable electric heater data tag (C) Daniel Friedman at Inspectapedia.com

Not all Portable Electric Heaters Using Plastic Show Signs of Overheating

The DeLonghi Ceramic Tower Heater shown below has been in occasional use in a New York Home since about 2006 without showing signs of browned plastic or other overheating indicators like those on the heater discussed above on this page.

Like most of the portable electric heaters we've found, installed, tested, this one, DeLonghi model # TCH8093ERL, was also made in China.

Delonghi Ceramic type Tower Electric Heater (C) Daniel  Friedman at InspectApedia.com ... Delonghi Ceramic type Tower Electric Heater data tag and serial number help find heater age (C) Daniel  Friedman at InspectApedia.com

From the DeLonghi heater's serial number shown above, 188514090564 and from examining the print date of the instructions provided with this heater (05/05/01) we think this heater was manufactured in 2005.

Portable Electric Heaters that use Fewer Plastic Components

It can be a bit of a challenge to find an inexpensive portable heater that seems safer for long-term use than the plastic-ridden model we show above.

In an informal survey of a large building supply store in Duluth MN (Menards) in October 2022, of about forty different portable heaters on display, there was only one that used pretty much all metal parts - shown just below.

However there are a number of better made, and more expensive, portable electric heaters available including models with little or no plastic (that might or might not be combustible - Ed.) as we will describe below.

Milk House Heaters - simple, probably more safe portable electric heaters

Milk house all metal heater - (C) Daniel Friedman at InspectApedia.com ... Milk house all metal heater - (C) Daniel Friedman at InspectApedia.com

Above: the "milk house" style utility heater shown uses almost no plastic except for its control knobs. Sold at building suppliers, this portable electric heater was also very inexpensive: about $30. U.S. at Menards in Duluth, MN.

Features include a "freeze-protection" setting that turns on the heater when temperatures approach freezing, two heat ranges (we run it on 1300 Watt but it also has a 1500 Watt setting) and an adjustable thermostat that is impossible to read. (We taped a tiny bit of blue masking tape on the control knob to serve as a more-visible pointer). - source: comfortzoneproducts.com

Watch out: however this low-priced heater is also

Other portable or wall-mounted electric heaters to consider

Konwin electric heater, portable, metal (C) Daniel Friedman at InspectApedia.com

Above: a (nearly) all-metal portable 1500 Watt infrared heater from Konwin: Konwin Infrared Zone Heater Model No. GD9315BCP-6.lb

Portable Glass-Faced Electric Heater

White glass faced Mill heater failure (C) Daniel Friedman at InspectApedia.com

The Mill heater shown above, Model SG1500GLASS, was attractive, used few plastic parts, and could be operated with or without its built-in circulating fan.

We tried this heater in the same northern Minnesota cabin as the others shown on this page. The heater worked well for three years, then in March 2021 it developed a rattle in its fan. The fan motor quickly died completely.

On contacting the U.S. vendor of this heater (Virtual Supply, Beaverton OR), we learned that it was purchased from an off-shore vendor, that it was no longer sold in the United States, and that no repair parts or repair service were available

The manufacturer, Mill International A.S., promptly refunded our purchase price (about $100. U.S.D) and this heater was discarded. Mill International stands behind their products, and similar heaters are still available in the U.S. and Europe.

Mill International AS, Grini Næringspark 10, 1361 Østerås, Norway Web: www.millheat.com

Portable OR Wall Mounted Electric Heater

Klarstein 2000 W portable heaetr, can be wall-mounted - cited & discussed at InspectApedia.com

The glass-fronted infra-red heater shown here as a wall-mounted unit is in use in the same building in northern Minnesota as the milkhouse heater discussed above.

Sold as a 2000W heater for about $130. U.S., this heater is sold in several sizes, wattages, and configurations including curved-front portable heater models and in prices from about $100. to $150 U.S.

The heater is sold with a wheel kit for use as a portable heater, or the wheels can be removed and a manufacturer-supplied bracket mounts the heater to a wall, as we've done below.

Klarstein wall mounted electric heater (C) Daniel Friedman at Inspectapedia.com

Research on Portable Electric Heater Failures, Fires, Safety

...Electro kindling example: plastic parts of this electric heater ignite and burn vigorously - Aronstein 1996 cited & discussed at InspectApedia.com .... Electro kindling example: plastic parts of this electric heater ignite and burn vigorously - Aronstein 1996 cited & discussed at InspectApedia.com


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