You are here

Comments for RV Electricity – Portable space heater safety, Part 2

    • I’ve been in contact with a few portable space heater manufacturers about this, and there doesn’t appear to be any published statistical data on the relative safety of each technology. However, we can draw some conclusions based on general ignition principals.

      So, any radiant heater with an exposed heating element that reaches combustible temperature is in the most dangerous category. So open element radiant heaters as well as Vicor tube elements (looks like a glass tube over the elements which glow cherry-red) would be on the top of my “most dangerous” list.

      Intermediate danger would be units with a completely enclosed wire heating element and a fan to circulate the hot air. But it’s critical that this type of heater has an over-temp shut-off as well as a tip-over switch. That way if the fan fails or the heater is knocked on the side, it won’t heat up out of control.

      Safer than that would be the self-regulating ceramic heaters with a fan. The ceramic element draws less power as it heats up, so the temperature is self limiting. However, it needs to have a tip-over switch to shut it down if knocked over.

      Finally, I would consider the radiator style oil-fill radiant heaters to be the safest of all, as long as it has an over-temp and tip-over switch. There’s no exposed element, the surface never gets hot enough to ignite combustible objects (normally), and there’s no fan to fail.

      However, ANY heater on high setting can overload an extension cord or cause overheating of loose/corroded outlet. So I wouldn’t run any of these on the HIGH setting for more than 30 minutes, and NEVER unattended or while you’re asleep. On the 1/2 wattage setting of 600 or 800 watts, the danger of electrical overload is reduced, so it’s probably safe to run them at the lower wattage for hours at a time. But you still will want to periodically put your hand on the outlet cover to inspect it for heating. And NEVER run one on a power strip as they’re usually cheaply constructed and prone to overheating. More to study later, but that’s my WAG from years of experience with electrical things that heat up.

  • The best answer is none of them, you’re better off using something like the CheapHeat system that is hard wired into your RV. Because it’s designed for a 100% duty cycle and has the built in safeties you need, like high temperature and over current protection. You can leave your RV unattended and don’t have to worry about it overheating and causing a fire.
    Plus it hooks directly into your RV’s central heating system so it heats the entire RV including the mechanical area where your plumbing and storage tanks are located.
    You can find out more about this at

  • Hi Mike,

    We have a fake fireplace in the rv that we love. The grounded cord has chromed looking plated blades on the plug. They seem very resistant to overheating and don’t discolor the way the brass colored ones do. I’ve also replaced the 30a plug on the shore power cord with one that has the same style chrome looking blades. This plug has not discolored and pitted the way my original did. It looks as though this coating or plated material is more resistant to overheating due to load

  • Ken: *MY* opinion, which I’m sure someone will disagree with, is that *I* use a hot-oil radiator in my RV. It’s not as small as my forced air, but it’s a LOT safer with 90lb dogs bounding all over. The surface stays safe to the touch, much less flammables (and I do use it to carefully heat and dry towels sometimes… naughty me!). Mine has a thermostat and heats 500sf trailer pretty well if running most of the time. I have lousy hearing, so running TOTALLY silent is a requirement in my rig.

    I would NOT count on the safety of ceramic heaters over “glowing” heaters. ALL the same safety concerns and practices apply, and never count on ANY supposed safety device to replace wiser practices. The ceramic heaters I’ve used CERTAINLY can set fires if capsized or mis-used!!!

    Yes, radiant heaters heat “line of sight” and feel instantly warmer on your skin although not warming “around the corner” immediately. That said, they DO heat the air quite effectively because they warm EVERYTHING LoS — so the cold cabinets and walls get slightly warm and themselves heat the air. Radiant loses points for safety because something VERY close to the heater will catch fire VERY quickly.

    If you DO use a small forced air, I used to put mine on my counter where it won’t be kicked over — and yes, never above 800W setting.

    Be safe… and toasty!

  • Kenneth,

    Probably the Cheap Heat system described above, followed by your propane furnace and finally the space heaters described in Mike’s article.


  • I use both a RV dehumidifier and a small pump house type electric heater to control humidity in my Class C during the winter storage. The RV is plugged in to 30w shore power. I am not concerned about the dehumidifier as it using little power. My question is the electric heater. I have been plugging it into one of my interior outlets. For long term use, such as over the winter, would I be better off using a 12gauge appliance rated extension chord and plugging it in outside my RV so as not to put strain on my RV’s electrical system?

  • Forced air space heaters include the fan wattage in the total watt rating. A 1000W
    Unit may only put out the 800W of heat…

    • Interestingly, if they have an 800 watt element and a 200 watt fan, they actually do heat up the room with 1,000 watts of heat. That’s because ANY electrical appliance that draws power, no matter if it’s 10 watts or 10,000 watts, heats up the room with that much electricity. As I’ve mentioned. all electrical heating is 100% efficient. So a 100-watt light bulb is actually a 100-watt heater, etc…

  • I left a question in the comments to Part 1 of this article: which is cheaper to heat, propane or electric. You answered, asking how much the cost per kilowatt hour was at the RV park where we’ll be staying is. I was finally able to get the kw/hr rate . The basic charge is $0.16 kw/hr for 246 kw/hrs/mo. It increases to $0.25 kw/hr thereafter. If we’re running it 8 hours a day, which will be cheaper?
    Thanks a million.

    • The data points you need are:

      1 KWh provides 3412btu
      1 gallon of LP provides 91,500btu

      Just multiply in your costs for each, and compare.

      • With the propane you need to take into consideration the efficiency of the furnace (Loss through the flue). That being if you actually do a flue gas analysis you’ll find that an RV furnace is about 60%. That means 40% of all of the gas goes out the flue as waste energy. Which means a 40,000 btu furnace only puts out 24,000 btus usable.
        But an electric heater is 100%, after you do the math $3.00 per gal propane = $0.18 per KW. so if you can get your electric for less that $0.18 KW it’s cheaper that $3.00 a gal for propane.
        Short story in most cases the CheapHeat Hybrid electric system is cheaper than propane.

  • When I bought my class C Jayco the rv technician told me to unplug the microwave and plug the heater in on that outlet because it was the only one rated for that high wattage

    • All your circuits should be rated for at least 15A.

      What your tech likely meant was that microwaves are usually on a dedicated circuit, so (by swapping for the only load on that circuit) the heater won’t have to share that amperage with anything else plugged in on the coach.

  • Leave a Comment