Staged warm air furnace schematic (C) Carson Dunlop Associates Electric Heating System Repair & Maintenance

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Electric heat installation & repairs:

This article 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.

Discussed here: Electric baseboard heater UL Standards, safety features, thermal cutoffs. What are the Different Types of Electric Heat in Homes? Electric heating boilers, Electric Furnaces, Electric convector heaters, Electric floor-mounted heaters, Electric toe-kick heaters, Electric wall mounted heaters, Electric radiant heat panels, Electric plenum heaters, Night storage heaters, Wesix™ type Wall & Floor Mounted Electric Heaters.

This article series answers most questions about all types of heating systems and gives important inspection, safety, and repair advice. Sketch at page top courtesy of Carson Dunlop Associates.

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Electric Heating System Inspection Methods, Diagnosis, Safety, Repairs

Fahrenheat electric wall heater (C) Daniel FriedmanElectric heat is about the easiest heating method to install, the least costly type of heating equipment to purchase, and in many locales, the most costly way to heat a conventional home.

Super-insulating a building, and paying special attention to drafts and air leaks can change that picture however, as can special electrical rates available from utility companies in some areas.

[Click to enlarge any image]

This article describes different types of electric heat in buildings and give some inspection and no-heat diagnosis tips for each.

Article Contents

Our photograph (above left) shows a Fahrenheat electric wall heater observed in a remodeled bathroom in a Poughkeepsie NY home and sold by Marley Engineered Products.

If you don't know what kind of heat your building uses, we explain how to figure out the answer at HEATING SYSTEM TYPES.

What are the Different Types of Electric Heat in Homes?

Electric baseboard (C) Daniel Friedman Overhead electric heater in a garage (C) Daniel Friedman

Electric heating boiler (C) Carson Dunlop Associates

Cadet wall mounted electric heater (C) Daniel Friedman

Electric Baseboard Heat Inspection - home inspector reports abnormally hot electric baseboards

Electric baseboard (C) Daniel Friedman4/14/14 Bill O'Callaghan said:

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, Bill O

Reply: Diagnosing 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

Bill UL 1042 20.1 confirms your observation:

The applicable standard for baseboard electric heaters, UL 1042 (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 (1997). The US CPSC reported on the hazards of "Fixed Position Electric Heaters" in 2002. - That study says 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.)

More safety inspection points for electric baseboard heat are at ELECTRIC BASEBOARD HEAT SAFETY.


Continue reading at ELECTRIC BASEBOARD FEET NEEDED or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.



Or see THERMOSTAT WIRING LINE VOLTAGE 120-208-240VAC - for electric heat

Or see these

Articles on Electric Heat

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