Choosing Electric Space Heater for Emergency.

Discussion in 'Electrical Forum discussion & Blog' started by molo, Nov 13, 2013.

  1. molo

    molo New Member

    Messages:
    840
    Location:
    cold new york
    Hello,
    I know that electric space heaters are sometimes the cause of electrical problems (breakers/fuses tripping, parts of the circuit overheating, heater overheating because of poor design/materials, etc). However, I am trying to select heaters to use while we wait for service in the event that the primary heat source goes out.

    1. How should I size the heater to be sure that it won't overheat the circuit or trip breakers?

    2. Are there any brands that are know to be good or bad?

    Thanks in advance!
  2. Glennsparky

    Glennsparky New Member

    Messages:
    22
    Location:
    Oviedo, FL near Orlando
    For 120V circuits, 1440 Watts will max out a 15A breaker. 1920 Watts will max out a 20A breaker.

    You have to add up the heater watts and the watts of anything else plugged into that circuit.
  3. Speedy Petey

    Speedy Petey Licensed Electrical Contractor

    Messages:
    991
    Location:
    NY State, USA
    This is not true at all. Why do folks insist on perpetuating this MYTH???

    1800 for 15A. 2400 for 20A.
    Continuous loads follow certain rules for circuit loading. A portable space heater is not considered a continuous load.

    I am no fan of space heaters. They cause more problems and fires than I care to know, but come on, facts are facts.
    Last edited: Nov 14, 2013
  4. DonL

    DonL Out of the Trades

    Messages:
    3,908
    Location:
    Houston, TX
    I like the cheap Walmart Lakewood.

    They are small and have a 750W and a 1500W setting.

    I have a few in use and always use the 750 Watt setting.

    1500 Watts is not safe for long periods.


    Have Fun.
  5. BobL43

    BobL43 DIY Senior Member

    Messages:
    1,786
    Location:
    Long Island, NY
    Long periods are not safe, and never fun. Sorry Don, had to say that.
  6. Dana

    Dana In the trades

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    Location:
    01609
    The little oil filled finned radiator types (DeLongi, and others) are quieter and safer from a fire-hazard point of than anything with a blower or radiant-reflector. Many/most come with dual elements a 600W and a 900W separately swichable, so you can have it pulling only 600W OR 900W if you don't think the circuit can handle 1500W), and an adjustable on-board thermostat to limit the surface temp of the unit. Shop around, and can usually find a pretty good one for under $50.

    [​IMG]
  7. Reach4

    Reach4 Active Member

    Messages:
    2,066
    Location:
    IL
    While they are not space heaters, infrared heaters can make you more comfortable for fewer watts. The infrared produced turns to heat when it hits your skin or clothes (or anything else). So if it points to your sitting position, you can be comfortable with a lower air temperature. They will still heat the room as as well as a regular heater for a given power, but the infrared will make you feel warmer for the same watts.
  8. Wet_Boots

    Wet_Boots Sprinkler Guy

    Messages:
    798
    Location:
    Metro NYC
    the Pelonis Disc Heaters were always touted for their safety, being that their thermistor heating elements never got fire-starting hot
  9. DonL

    DonL Out of the Trades

    Messages:
    3,908
    Location:
    Houston, TX


    Why do you need to confuse things with the facts ?


    People do operate them at 100% load when they get cold.
  10. Wet_Boots

    Wet_Boots Sprinkler Guy

    Messages:
    798
    Location:
    Metro NYC
    It is kinda interesting/significant that these things seem to max out at 1500 watts, which is just a hair away from 80 percent of a 15 amp load.
  11. Glennsparky

    Glennsparky New Member

    Messages:
    22
    Location:
    Oviedo, FL near Orlando
    Thank You, DonL.
  12. Speedy Petey

    Speedy Petey Licensed Electrical Contractor

    Messages:
    991
    Location:
    NY State, USA
    What's confusing?
    And what does "100% load" have to do with it?
  13. Speedy Petey

    Speedy Petey Licensed Electrical Contractor

    Messages:
    991
    Location:
    NY State, USA
    Please tell me where I can find this in the NEC. Thanks.
  14. DonL

    DonL Out of the Trades

    Messages:
    3,908
    Location:
    Houston, TX

    Nothing really.

    You are correct for the circuit being able to handle the load. The Line cord and plug won't last long.

    My 100% was about how people Put the heater on High, Blow and Go 100 percent of the time.

    Just because a Microwave Oven has 100% Power does not mean that you need to use it. Popcorn requires 100%.


    900 Watts is a good Max for what may be operating at 100 percent duty cycle and most likely is unsupervised.


    Just make sure to install a Smoke Detector near the heater and have 911 in quick dial to operate the 1500 Watt mode.
  15. Glennsparky

    Glennsparky New Member

    Messages:
    22
    Location:
    Oviedo, FL near Orlando
    Since the OP said "emergency" and "primary heat" failure, I could only imagine that the space heaters would be on the highest setting all night. Then I thought about how many back stabs the circuit might have gone through. As such, I only felt comfortable with numbers that reflected all loads being continuous.

    I admit to cowardice and cutting corners on my answer and I throw myself on the mercy of the court.

    But I still side with DonL's posts.
    Last edited: Nov 15, 2013
  16. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,531
    Location:
    North Carolina
    It is not the breaker that has a limit to the amount of amperage that can be plugged in but the receptacle has a limit that can be found here
    Table 210.21(B)(2) Maximum Cord-and-Plug-Connected
    Load to Receptacle

    For a 15 amp receptacle be it on a 15 or 20 amp circuit the max load is 1440 watts
  17. Speedy Petey

    Speedy Petey Licensed Electrical Contractor

    Messages:
    991
    Location:
    NY State, USA
    My point exactly.
    I think people confuse this section for cord and plug connected equipment with total permissible circuit load, which is found in 210.24.
    IMO if a plug fits the receptacle the load is OK. For instance, how can a 1500 watt heater, or an 1875 watt hair dryer legally come with a 15A plug since 210.23(A)(1) deems it illegal? The wattage ratings are either skewed, or they have some sort of "by" with regard to the code.
  18. DonL

    DonL Out of the Trades

    Messages:
    3,908
    Location:
    Houston, TX
    I have a Heater that has 1300 or 1500 W and it will heat the internal thermostat so that it cycles on and off even if room temperature is cold.

    That helps to save the outlet, but if it wasn't for the High Temperature Line cord then you could have problems, It does get Hot.

    When the plug gets dirty, a little resistance makes a lot of heat when powering a 1500 Watt load.


    Some of the Low Wattage heater models are good to run off of a portable generator.

    Wood may be better for emergency heat. Or a Fat Lady, but food is expensive.


    Have fun.
  19. Wet_Boots

    Wet_Boots Sprinkler Guy

    Messages:
    798
    Location:
    Metro NYC
    speaking of high-temperature line cords, is it no longer possible to get some heater line cord (HPN) cut to length at a hardware store - I haven't seen any offered that way for years and years
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