Electric Heating System Repair & Maintenance

Electric Baseboard Heaters

Electric baseboard heat (photo above) is installed on (usually exterior) walls in occupied rooms.

The number of linear feet of electric heating baseboard (and some other parameters) along with the rated electric output in BTUs/hour per linear foot of baseboard determine how many watts of electric heat is provided.

See details about electric baseboard heat at

• ELECTRIC BASEBOARD HEAT DIAGNOSE REPAIR - home
• ELECTRIC BASEBOARD FEET NEEDED
• ELECTRIC BASEBOARD HEAT INSPECTION
• ELECTRIC BASEBOARD HEAT INSTALL
• ELECTRIC BASEBOARD HEAT SAFETY

Electric heating boilers 

Electric boilers are commonly used as a backup heat source for heat pump systems or for small radiant floor heating systems (such as our Minnesota radiant floor heat project that was a total failure and that is detailed

at RADIANT HEAT MISTAKES).

Carson Dunlop Associates Associates' sketch above illustrates an electric heating boiler used for residential heating systems.

Also see ELECTRIC FURNACE MAN (EFM) BOILERS 

Electric Furnaces

Electric furnaces can provide warm air heat; the Carson Dunlop sketch shows how we figure the equivalent heat between an electric furnace (in watts) and a gas or oil fired heating furnace (in BTUs).

An example of an electric furnace is described

at WHIRLPOOL VARIABLE SPEED ELECTRIC FURNACE MANUAL [PDF] (2003)

Electric Convector Heaters

Electric convector heaters with fans such as the ceiling mounted garage heater shown above are used most often for irregular use in larger cold spaces such as a garage or workshop.

But also see wall-mounted electric heaters, below. Similar units that use hot water or hydronic systems - hot water heated fan convector heating units - are discussed

at FAN CONVECTOR HEATERS - HYDRONIC COILS.

Electric floor-mounted heaters



as this Carson Dunlop sketch shows, an individual electric heater can be mounted right into the floor surface (instead of along a wall).

Watch out for kids dropping crayons or things that can catch fire into the grates of heating equipment like this.

As the drawing points out, flush-floor mounted electric heaters are used where heat is needed in front of a sliding door (and where no wall is available to mount a heating baseboard.)

Watch out See this floor mounted electric heater example that has safety concerns.

WESIX™ TYPE WALL & FLOOR MOUNTED ELECTRIC HEATERS

Kickspace Heaters

Electric toe-kick heaters (kick-space heaters or toekick heaters) are mounted in bathrooms and kitchens as this Carson Dunlop sketch shows.

We use a kick space heater (which are also available for hot water heating and warm air heating systems) where a room lacks wall area to mount a conventional heat source.

Wall Mounted Electric Heaters

Wall-mounted electric heaters are widely used in locations where extra heat is needed or where it was not convenient to route ductwork or piping for warm air or hot water heat.

Wall-mounted heaters are usually recessed or flush mounted such as the Cadet™ electric heater shown above. and in Carson Dunlop's sketch below.

These heaters are often used in hallways, entrance foyers, bathrooms, and other locations where spot heat is needed.

Watch out: see this CADET HEATER MANUALS & CADER / ENCORE HEATER RECALL [web article] for a safety recall on this heater type.

And see WESIX™ TYPE WALL & FLOOR MOUNTED ELECTRIC HEATERS - where we include additional safety warnings.

Radiant Panel Electric Heaters

Electric radiant heat panels have been installed in homes for over 50 years. Above is a sketch of a typical radiant heat ceiling layout.

Electric radiant heat in ceilings was produced as both wires imbedded in gypsum board (drywall) and as wire panels taped to the upper surface of the ceiling drywall.

Electric radiant heating panels are also available that fit perfectly into a suspended ceiling grid.

See details about electric radiant heating panels and controls beginning

at RADIANT HEAT - home

Electric Plenum Heaters

Electric plenum heaters, usually ceiling-suspended, are used as supplemental heat on combination fuel warm air systems such as wood fired furnaces [Image] possibly on warm air systems heated by a HEAT PUMP [web article].

Electric plenum heaters are designed and approved for safe use in concealed spaces such as crawlspaces or drop ceilings where the heater may not be readily accessible and where space is limited.

These heaters are also used for free air discharge from a building or within building air duct systems to provide supplemental heat. For residential application their most-common use might be for freeze protection in crawlspaces.

Shown above: a plenum-rated unit heater from Marley Engineered Products, described by the manufacturer as

This zero-clearance, plenum-rated unit heater fits unobtrusively into unique spaces where you need freeze protection or extra comfort for occupants. It even connects to existing ductwork, making it easy to integrate with your buildings environmental system.

Plenum-rated approved for installations in concealed spaces (between finished ceiling and drop ceiling, plenum space, or inside a plenum). It may be installed in areas that are not readily accessible and may be installed for freeze protection

Night Storage Heaters

Night Storage Heaters are used as auxiliary heat source and to balance heat in climates where central heating is not usually installed or where supplementary electric heat is required such as for freeze protection in crawlspaces.

Details are at NIGHT STORAGE HEATERS & HEAT SINK RADIATORS

Portable Electric Heaters

Portable electric heaters like the electric heater we show just above are intended for temporary use as supplemental heat.

This category includes including milkhouse heaters & ceramic or infrared heaters & portable baseboard heaters.

Be sure to review PORTABLE ELECTRIC HEATER SAFETY and also

Watch out: Some portable heaters may present a risk of fire, as we explain

at PORTABLE ELECTRIC HEATER FAILURES - separate article, safety warning for some heaters,

Wesix Electric Heater Safety

Above: a Wesix floor-mounted electric heater.

Below: Page from a Wesix Electric Heater Company Catalog. The San Francisco company was located at 390 First St., San Francisco CA with offices in nine other U.S. cities.

Watch out: Wesix electric heaters are no longer made nor are replacement parts readily available. More important, these heaters do not contain safety features found on newer electric heaters.

If you have a Wesix electric heater, for safety we recommend that you turn it off and have it replaced.

As early as1945, Wesix also licensed some of their electric heater design to other companies such as Westinghouse Electric, as reported by the New York Times.

• Wesix™ type Wall & Floor Mounted Electric Heater Safety Warnings: (illustrated just above and below)
  
  We have received sporadic field failure reports of Wesix heaters and multiple sources warn that these older heaters are not considered safe.
  
  Wesix electric heaters were made by the Wesix Electric Heater Company [WEH], a California company, chartered originally in 1938 and again in 1942, and headed by Thomas J. Mellon.
  
  Wesix™ electric heaters were often installed in bathrooms, in floors as a small fan convector unit, and as electric baseboards, including both 120V and 240V models that included a brass data tag on the bottom of some units.
  
  The company also made the Wesix Mark IV ion collector used in researching the effect of ions on microorganisms and other biological materials.

• Wesix heater product identification & electrical data:
  • Wesix DHF-30T In-Wall Fan Forced Electric Heater 3000 W
  • Wesix DHF-20 In-Wall Fan Forced Electric Heater 2000 W
  • Wesix IN-FLOOR FAN HEATERS [image]
  • Wesix 220 VAC 6.8 A, 1500 watts
  • Wesix 120 AC, 15CHM-1-G-29-01
• Possible Wesix electric heater (and similar product) concerns to be noted by owners or home inspectors:
  • overheating covers
  • age and reliability, including loose or corroded connections leading to loss of heat (easily repaired) and burned-out heater element (replace the unit) - neither of these defects are peculiar to this brand nor to a particular model (as reported
  • Inoperative thermostat or controls

Can our Wesix electric baseboard heaters be replaced?

Can this heater be replaced?? I need the same dimensions as above,the box is 33' long, 6 and 7/8" wide and 3and1/8" deep. The in wall heater to be replaced is in a metal box that measures 33 inches long, not feet!! 3 and 1/8 inch deep and 6 and 7/8 inches wide. It is in a 1950's house.

Wesix serial number sf681161 1500 W,12.5 amp. Is there a replacement??? viccimartini@yahoo.com Nov 3, 2012) vicci Martinazzi

Reply:

Vicci,

Wesix electric heaters can not be repaired safely.

But an electric wall heater can be replaced; provided that the feeding circuit is properly wired and sized and fused, it should be a minor matter to remove the old unit and, if you don't find a replacement that fits perfectly in the existing opening, changing the opening size is basically trivial carpentry and drywall work.

Where to get Parts for a Wesix 240-V in-wall heater

Hi - I have an older Wesix 240v in-wall electric heater that has a strange copper tube attached to a wire coming out of the fan switch box.

I assume it is related to temperature control, but I can't find any info on it. Anyway, the copper tube broke away from the attached wire the other day and left a strong chemical smell in the air that I couldn't identify.

It looks as though I could solder it back on the end of the wire, but I'm not sure it would work if the fluid has spilled from the tube. Does anyone have any suggestions on this problem? Thanks. (Feb 5, 2014) Darrell

Reply: parts not available, replace the heater

Darrell, perhaps you could send us some sharp photos - using the CONTACT link found at page top or bottom. I'm not sure, but if what broke was a temperature sensing device the system will not work safely without it.

Watch out: In general, because they lack modern safety features, we recommend replacing rather than trying to fix and use an old Wesix electric heater.

We have 5 Wesix heaters - two run by an FPE wall thermostat - that stopped working.

COMMENT:We have a mountain home built in the 70s. We have 5 WESIX electric baseboard heaters.

The two in the living/dining room areas are run by one wall thermostat (the name on that says "FPE), and have stopped working.

We mostly use our wood stove to heat this area and rarely even need the baseboard heaters, but this has been a cold winter and we need them to work.

How can we diagnose the failure.: eaters vs thermostat?

We're ok with buying a new thermostat but don't know anything about required voltage, wiring, etc. Is it possible the heaters went out? We're lost! On 2016-02-21 by Leo (no email)

by (mod) - Double Hazard: FPE + WESIX electric baseboard heaters

Leo:

Watch out: they lack modern safety features: we recommend replacing rather than trying to fix and use an old Wesix electric heater.

Given the poor track record of some FPE equipment such as its circuit breakers and electrical panels, and given that your FPE controller has failed, it would make sense to have a new replacement electric baseboard heat thermostat installed when you replace your unsafe and failed Wesix heaters.

They're pretty generic and are widely available.

Your electrician may want to take a look at your present installation, but generally it's a simple 240V circuit.

The circuit should be traced starting at the electrical panel (is each circuit breaker on?) through the individual thermostats and on to the heating elements in the baseboard heaters.

Watch out: See FEDERAL PACIFIC FPE HAZARDS

Reader comment: Max says: said: Safety is always the #1 concern and you have effectively addressed the issue. Informative and well-focused. Great work! Regards from Max Stout (May 10, 2011)

Electric Baseboard Heat Inspection, Safety

Above: Carson Dunlop's sketch above points out an approach to sizing electric baseboard heaters, based on a rule of thumb of about 5 to 8 watts per square foot of floor space.

See these

Electric Baseboard Heat Articles

• ELECTRIC BASEBOARD HEAT DIAGNOSE REPAIR - home
• ELECTRIC BASEBOARD FEET NEEDED
• ELECTRIC BASEBOARD HEAT INSTALL
• ELECTRIC BASEBOARD HEAT SAFETY

Below we describe an unsafe electric baseboard heat installation.

Home inspector reports abnormally hot electric baseboards

An inspectApedia reader who is a professional home inspector reported:

While doing a home inspection, I viewed the electric baseboard heaters with a thermal camera. Internal, core temps began around 160* which seems the norm, but when I went into the bathrooms, the shorter registers emitted 225* and were only on for a short period.

I recommended further evaluation, then spent a bunch of time researching the web for a safety document concerning this. I believe the units have been designed with thermal shut-offs since 1983 and should be Listed and labeled since 1995?

What about "Commercial" IE Condo's or apartments? Thanks, 4/14/14 Bill O'Callaghan

Reply: Diagnose an electric baseboard heater that's too hot or won't shut off

Hi Bill, that's an interesting observation giving us some data on IR scans of electric baseboards. I understand that some electric baseboards (such as some Cadet models) indeed have a built-in upper limit switch.

But note this quote from the heater's installation notes

More important, you may have saved someone from having a house fire.

One Cadet document I reviewed emphasized that all Cadet baseboard heaters require a thermostat though in a Cadet installation manual from another source I read that wall thermostats are optional.

Presumably they meant that if you're not using a wall thermostat you must use a thermostat installed in the baseboard at one of its ends. The company gives these diagnostics for electric baseboards that don't shut off (paraphrasing)

1. Heat loss from the room is greater than the baseboard's output
2. The baseboard thermostat is defective
3. The thermostat is not wired correctly
4. Room temperature is below thermostat set temperature.

They don't mention a failure of an internal temperature limit as a defect, but that concern does show up in the standard as I will quote.

Standards for Fixed-in-Place Electric Heaters: requirement for a thermal cutoff

UL 1042 20.1 Standard for Safety of Electric Baseboard Heating Equipment [PDF] (1994) (local copy saved as UL-1042.pdf) confirms your observation:

The applicable standard for baseboard electric heaters, UL 2021, Standard for Safety for Fixed and Location-Dedicated Electric Room Heaters (1995) is a voluntary one. Thermal cutoffs are discussed on p 31 and 32 of that lengthy document:

UL 1042 20.1

"A Thermal cutoff shall be secured in place and located so that it will be accessible for replacement without damaging other connections or internal wiring."

UL 1042 20.2

A thermal cutoff shall open the circuit in the intended manner without causing the short-circuiting of live parts and without causing live parts to become grounded to the enclosure when the heater is connected to a circuit having a voltage in accordance with 33.1.21 and operated in a normal position to cause abnormal heating.

A second standard applies to certain other electric heaters: UL 2021 STANDARD FOR SAFETY Fixed and Location-Dedicated Electric Room Heaters (1997). The US CPSC reported on the hazards of "Fixed Position Electric Heaters" in 2002. - www.cpsc.gov//PageFiles/117191/fpheater.pdf (Dead Link 2025/11/05) Here's a free "preview" copy of

UL 2021 STANDARD FOR SAFETY Fixed and Location-Dedicated Electric Room Heaters [PDF] from normsplash.com - retrieved 2025/11/05, original source normsplash.com/Samples/UL/149618875/UL-2021-2021-en.pdf

That study said that the thermal limiter you describe is included in a "typical heater".

UL Standards Exclusions for Commercial Properties

About an exclusion of applicability of the UL Standard for commercial installations of electric baseboard, I didn't see anything in the UL Standard nor in the US CPSC hazard analysis that would exclude these same heaters from having the required safety features in particular applications such as "Commercial" use or in Condos or Apartments.

Furthermore, how would a manufacturer of a particular electric baseboard heater model know the classification of the building into which it is to be installed?

Thermography & Electric Baseboard Heat: detection of abnormal conditions can warn against a building fire

Bill you may not have come across it but over

at THERMAL IMAGING, THERMOGRAPHY in a series of articles, we've been working with Paul PRobett from Incodo (New Zealand) to report on what can be useful and what should be viewed with caution when using thermal scanning of any sort.

And I've had my own little excitement: using a little Exergen thermal temperature sensor to look at some aluminum-wired baseboard heaters during a home inspection I found that one heater was much hotter than its brothers.

I warned the owner about an aluminum wire overheat and fire risk and was nearly run off the property by the volume of his scoffing. That night the house burned down. Luckily no one was injured.

My view is that we can make some use of temperatures mostly by comparison such as in the case I just described. I suspect that unless we are measuring a black emitting surface our temperature readings are not precise.

Your comparison of "much hotter" among some units was the important observation. (Cadetheat has a useful table of wattage output for different baseboard lengths and voltages that may be useful to compare with your field scans.)

Overhead & Garage Heaters - Electric, Hydronic, or Gas

Above: an electric garage heater suspended from the ceiling in a garage workspace.

Below we show another example of "spot heat" for a garage work area using an overhead water to air fan convector unit, a fan coil heater hung from a garage ceiling.

This heater type is discussed at FAN COIL & FAN CONVECTOR HEATERS & HYDRONIC COILS and may use electricity as a heat source or it may obtain heat from piping from a hydronic (hot water) heating boiler.

Other examples of low profile and overhead heaters:

• DORNBACK UNI PAK LOW PROFILE HEATER INSTMANUAL [PDF] GH & DGH-Series Uni-Pak heaters
  
  Excerpt:
  
  This appliance is a gas-fired power vented unit heater with propeller-type fan, designed for suspended mounting in commercial, industrial and residential buildings. The unit heater is completely assembled and wired. Only the usual mounting brackets, gas, electric and flue connections' are needed to put heater into operation.

Watch out: some overhead heaters used in commercial installations are not safe nor approved for home use, such as Dayton's High Intensity overhead heaters that are described at DAYTON GAS HEATER MANUALS & CONTACT INFO