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Electric heater on shore power
#11
A oil filled heater takes a while to get going but once it is hot the heat is constant with out the noise of a fan. I used both a full sized one set to low on one end of my trailer and a small 400w version on the other end when it was well below freezing in Denver last month. I also had a small fan on the big one to help push the heat around.
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2011 Ameri-lite 25 ft bunkhouse with 750w of solar and a 675 Ah bank
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Itripper (12-04-2017)
#12
(12-03-2017, 04:56 AM)hugemoth Wrote: Watts is Watts when it comes to heat output by electric heaters. More Watts means more heat.  There are of course differences in how you feel the heat. Convection, radiation, etc.. Quartz, ceramic, nichrome heating element, doesn't matter as far as BTU output.

I don't think this is true. There are efficiencies involved. Here are space heaters with measured wattage:
(h,m,l=hi,med,low   os=oscillating   f=fan   i=idle)


Lasko Ceramic (upright): (hi/os)1311/1312,  (lo/os)930/934, (i)1.2w
Pelonis (walmart $10): (h)1175  (m)772  (l)528  (f)14
Presto Heat Dish ($60 Costco): H-820  M-816  L-820 (strange numbers but true)
Tatung Heat Devil:  (h)1070   (l)750   (fan)

Hot Plate (Harbor Freight $9): (828w)
Hot plate iMUSA $10 (900w)  (just purchased, not used much yet)

In my van, the best is the Presto Heat Dish, especially for almost immediate warmth.  Coming in #2 was the HB Hot Plate placed on the floor.

I'm using the Hot Plate now and ditched the Presto because it's huge, like a satellite dish. It wastes a lot of space when not used in the hot/warm months. The hot plate also cooks stuff and keeps a constant supply of hot water. Doesn't take long at all to boil a full kettle to be saved in thermoses, hot water bottle, etc. And it's just tiny for space saving. I use a splatter guard + grill on top to keep things form accidentally dropping on it and causing a fire.

Next up would be a cast iron dutch oven on it to retain the heat better. This should work. It's not that cold here yet, but I will find out when it does.
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#13
+1 on the oil filled radiator style.
I used to keep one running in my trailer in my driveway during the winter to keep my racing stuff from freezing (had a thermostat I set to 65 degrees).
After selling the trailer, used it in my living room and lowered the house thermostat....saved $$$.
I'm taking care of my procrastination issues;
Just you wait and see.
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#14
(12-03-2017, 11:16 AM)GrayWhale Wrote: I don't think this is true. There are efficiencies involved.

It IS true.

Many are mislead by advertising claims and website mis-information. 

Electric heating elements are always 100% efficient. This is a fundamental law of physics and electronics. There is no energy lost: 1500 watts of electrical power in, equals 1500 watts of heat energy out. What you do with it after that is what matters. (if the heating element 'glows' then there is a tiny amount of energy being used to create light)

What gets tossed into the mix are electronic control circuits, lights, indicators, and fans which use a tiny (miniscule) amount of energy compared to the heating elements. 

So heater A might state it's 'more efficient' than heater B, when actually the the difference is less than .01% and that is due to the indicator light and a fancy digital display on heater B.

There are also differences in the way the heat is delivered and 'felt'. A very small (but still 1500 watt) ceramic heater will simply feel 'hotter' when you place your hand near the opening, where a 1500 radiant heater that is much larger wont even come close to burning you, although it will still feel pretty hot. 

They BOTH put out about 5100 BTU.

Then a few years back they came out with expensive and very nice looking 'infrared' heaters, also 1500 watts, that claimed whole house heating.

Still 5100 BTU or close to it. 

You just can't cheat physics with a fancy cabinet and a high priced ad campaign.

BTW, in Europe and other countries with standard 220-240 volt household wall supply, they have portable heaters with up to 3000 watts or so, putting out over 10,000 BTU. 

Now that would warm up a bus!
Never trust a camp cook with lots of shiny new pans...
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#15
(12-03-2017, 12:23 PM)tx2sturgis Wrote: It IS true.

Many are mislead by advertising claims and website mis-information. 

Electric heating elements are always 100% efficient. This is a fundamental law of physics and electronics. There is no energy lost: 1500 watts of electrical power in, equals 1500 watts of heat energy out. What you do with it after that is what matters. (if the heating element 'glows' then there is a tiny amount of energy being used to create light)

What gets tossed into the mix are electronic control circuits, lights, indicators, and fans which use a tiny (miniscule) amount of energy compared to the heating elements. 

So heater A might state it's 'more efficient' than heater B, when actually the the difference is less than .01% and that is due to the indicator light and a fancy digital display on heater B.

There are also differences in the way the heat is delivered and 'felt'. A very small (but still 1500 watt) ceramic heater will simply feel 'hotter' when you place your hand near the opening, where a 1500 radiant heater that is much larger wont even come close to burning you, although it will still feel pretty hot. 

They BOTH put out about 5100 BTU.

Then a few years back they came out with expensive and very nice looking 'infrared' heaters, also 1500 watts, that claimed whole house heating.

Still 5100 BTU or close to it. 

You just can't cheat physics with a fancy cabinet and a high priced ad campaign.

BTW, in Europe and other countries with standard 220-240 volt household wall supply, they have portable heaters with up to 3000 watts or so, putting out over 10,000 BTU. 

Now that would warm up a bus!

That's nice, but it's not true when I've already proven to myself that certain heaters do work better at a lower wattage. And I didn't just buy all of these different space heaters for fun....nor decided that it was also fun to stay colder with a certain heater just because it used more juice.
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#16
(12-03-2017, 12:30 PM)GrayWhale Wrote: That's nice, but it's not true when I've already proven to myself that certain heaters do work better at a lower wattage. And I didn't just buy all of these different space heaters for fun....nor decided that it was also fun to stay colder with a certain heater just because it used more juice.

If you sit near a radiant space heater glowing orange, it will certainly feel warmer and heat you up 'better' than a radiant oil filled heater that is trying to heat an entire room before you can feel the warmth.

Like I said, its what you do with the heat after it is created that makes us feel the warmth differently. 

In the case of the OP's question we are trying to heat up a living space. So in that case, one 1500 watt heater will be about equal to any other, in terms of getting the most heat into the vehicle, assuming all the heaters we compare are the same wattage.
Never trust a camp cook with lots of shiny new pans...
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MrAlvinDude (12-03-2017)
#17
I bought a Vornado from Amazon, and it’s keeping me warm at night. I’m in a van and I haven’t insulated it yet, and it’s been down in the 30s
https://www.amazon.com/dp/B00MB4BQ0G/ref...9wbSAaxPth

I tried a radiant heat one from Walmart and TT was too hot if close enough, and not warm enough if further from me.
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tx2sturgis (12-03-2017)
#18
BTU is BTU, but **no way** are the different units equal in performance wrt your human comfort.

I know for a **fact** that the old Pelonis disc units get a freezing cold space up to comfortable a **lot** faster than any of the newer ones of the same type. Only downside is a noisy fan.

All are 1500W.

The oil-filled ones take forever. Yes quieter and maybe more efficient once just maintaining, but in no way useful when coming home to a very cold room.
The large infrared blower ones are a good compromise if you're only buying one. Best IMO to get two, different types.

Those 30y.o. old Pelonis can go for $50 on eBay when new ones are under $20. Same watts, but same BTU? I dunno don't care, I see one listed for under $30 I try to snipe it.
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#19
(12-03-2017, 01:41 PM)John61CT Wrote: The oil-filled ones take forever. Yes quieter and maybe more efficient once just maintaining,  but in no way useful when coming home to a very cold room. 

Yep, they really need to be left on keeping the room warm. (although some newer ones have 24 hour timers) ..they are not 'fast' heaters...never said they were. And they are heavy and take up a fair amount of floor space. 

But they are safe around pets and children, quiet, and will last for decades. I have two, and one of them is at least 20 years old. Many (but not all) of the fan or blower type space heaters will have a motor bearing failure within 5 years if heavily used. Those little brass bushing-type shaded pole induction motors are made pretty cheaply.

Different strokes for different folks.
Never trust a camp cook with lots of shiny new pans...
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#20
(12-03-2017, 12:30 PM)GrayWhale Wrote: That's nice, but it's not true when I've already proven to myself that certain heaters do work better at a lower wattage. And I didn't just buy all of these different space heaters for fun....nor decided that it was also fun to stay colder with a certain heater just because it used more juice.

I hear your experience. The way we experience and feel heat is indeed rather important (is it blown in our general direction, does it keep ones feet/hands/head warm, and so forth) , or is it simply being collected at the sealing, where it essentially do us no good. 

So how you direct the heat that you do have, makes a great difference. And how we keep it close to our bodies, that is vital.  
So I hear you when you talk about heaters that work for you or do not work for you. 


The point about how much heat comes from 1 Watt and how many BTU's that is, can however not be argued. As it is one of the laws of physics! 
And that a standard 110V, 15A fuse sets a limit for how many watt one device can draw, and convert into heat, that can also not be argued.

Except about those minuscule details when energy is converted to light, and not to heat.  But they are still minuscule, no matter the light source, as all the light sources we know of, are only able to convert a very small amount of energy into actual light. And there is always a rather huge heat generation "penealty". 

So when it comes to heating our living spaces, the amount of heat that a device can give, per watt of electricity available to it, is very straight forward. 


What is however NOT straight forward, is how much of that heat, is possible to stay close to your body, and thus help you to keep warm. 


I once lived in a flat,  that basically never got heated. Heat was only applied like, one hour a day. And no matter how I dressed, or how many layers of blankets, covers and sleeping bags that I piled on top of me - I simply could not keep warm at night. 

Until...... I put an electric heating blanket underneath me!  Then I could stay warm at night. 


So, my point is, that it very much matters how close to your body you can keep the heat that does get produced. 
And in a drafty place, limiting the amount of draft, around your bed, makes a difference. 


And if you can place the heat source under you, so the heat has to pass around your body, as it rises towards the ceiling, that will also make a very noticeable difference. 

Like, if you can safely heat the space under your bed, then the heat will keep your entire bed warm, as heat rises. 

So if you direct the warm air from a blower, to go under your bed. Or place one of those oil-filled heaters under your bed. And limit the escape path of the air (could be done with cardboard or blankets or...) then you will find that you do not really need very many watts to keep you warm. 


And I suspect that this is why GrayWhale's experience is, that some heaters work better than others. As methods were found, where it was not the entire space, nor all the walls and ceiling that was heated, but mainly the air surrounding you body. 

Does that make sense?
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Matlock (12-04-2017)


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