Electric Underfloor Heating?

[dr_nelson]

Hey y'all,

Has anyone ever installed an electric underfloor heating mat in the vehicle?
Something like this: youtube video

I know the propane heaters are very popular, but for some reason I am thinking about safer options right now; not sure if I will go this route, though.
But since I haven't found anyone actually doing it in a vehicle, I am suspecting that it is not a good idea. I only found this guy who is thinking of doing it (but has not done it, yet): guy talking about underfloor heating in a van

Any feedback appreciated.

 

[Every Road Leads Home]

How would you power it? You'd need shore power or a generator. Why fuel a generator to get heat when you can fuel the heater direct....ie propane heat.

 

[highdesertranger]

using electricity to heat anything is very inefficient. doesn't matter what voltage you are using or AC or DC. highdesertranger

 

[dr_nelson]

How would you power it?  You'd need shore power or a generator.  Why fuel a generator to get heat when you can fuel the heater direct....ie propane heat.

I don't know jack about electrical stuff (yet).
But looking at this one for example, it uses 1 amp and 120 watts, which I believe you could run during the night from a decent house battery, no? Of course, I would need an inverter... and a lot of patience, as this would never create instant heat like a propane heater.

 

[dr_nelson]

using electricity to heat anything is very inefficient.  doesn't matter what voltage you are using or AC or DC.  highdesertranger

Ok thanks... well I guess I am going to build a propane-tank compartment with a vent-hole in the floor. And good thing I have not ordered the expensive Origo 3000 alcohol stove; now I can go with an "ordinary" propane stove.

But still wondering. Someone must have installed underfloor heating.

 

[TMG51]

I don't know jack about electrical stuff (yet).
But looking at this one for example, it uses 1 amp and 120 watts, which I believe you could run during the night from a decent house battery, no? Of course, I would need an inverter... and a lot of patience, as this would never create instant heat like a propane heater.

That's gonna use more amperage over 12vDC than 120vAC. Short answer, it's still not feasible to run off-grid. SternWake will be along to berate you with maths shortly.

 

[SternWake]

120 watts at 12v it 10 amps

10 amps for 8 hours would be 80 amp hours consumed

Add 20 AH for inverter inefficiency.

A hundred amp hour battery under a 10 amp load, is no longer a hundred amp hour battery but best case scenario is a 80 Amp hour battery due to peukert effect.

120 watts of heat is not going to accomplish much and a good portion of that heat installed under a van floor, will escape below van body.

the Idea has little merit without a HUGE battery bank, and HUGE recharging sources, or being able to plug into the grid.

I have a 200 watt electric heater. On my inverter it pulls 16 to 19 amps. It does not accomplish much either in my lightly insulated van even when i am plugged into grid and power it continuously from sundown to sunup
. I only use it on the inverter for about 15 minutes when I take it under my covers with me, knees tented, to warm the cold bed.

Much better to use a 12v mattress heating pad in such a scenario.

And Electric heat is nearly 100% efficient, it just requires a huge amount of electricity produce enough heat to be effective.

 

[highdesertranger]

1a @ 120vAC converts to about 10a @ 12vDC, not counting the inefficiencies of the invertor. invertors range from 70-90% efficient. so you would loose between 10-30% there. plus 120 watt heater isn't going to do squat. don't worry we all had to learn at some point. highdesertranger

 

[JT646]

using electricity to heat anything is very inefficient.  doesn't matter what voltage you are using or AC or DC.  highdesertranger

Respectively disagree.  Properly done, it might make a lot more sense than heating the air (propane heater, etc.).   Heating the air is actually quite inefficient--as the heat is lost when the air is ventilated (vent, air leaks, etc.).   A well insulated van with underfloor heating is much less affected by ventilation since the heat is stored in the mass of the floor--and anything attached to it.    One could heat up the floor (and attached mass) while driving (alternator power) and then power it intermittently off a battery bank. 

 If this guys system works out (  ) he might be the envy of many a van camper.     Remember just because it's not common doesn't mean it's not practicable.

 

[John61CT]

Radiant heat is actually very efficient in principle, warm your body directly, not the air, walls furniture etc.

There are many 12v vented propane units that eliminate the moisture and unsafe CO issues, some like Propex VERY efficient.

Here's a low-volt floor setup, still need lots of electricity but at least not through an inverter

https://www.proudgreenhome.com/blog...-go-for-safe-comfort-in-rv-motorhome-or-boat/

 

[TMG51]

120 watts at 12v it 10 amps

10 amps for 8 hours would be 80 amp hours consumed

Add 20 AH for inverter inefficiency.

A hundred amp hour battery under a 10 amp load, is no longer a hundred amp hour battery but best case scenario is a 80 Amp hour battery due to peukert effect.

120 watts of heat is not going to accomplish much and a good portion of that heat installed under a van floor, will escape below van body.

the Idea has little merit without a HUGE battery bank, and HUGE recharging sources, or being able to plug into the grid.

I have a 200 watt electric heater. On my inverter it pulls 16 to 19 amps. It does not accomplish much either in my lightly insulated van even when i am plugged into grid and power it continuously from sundown to sunup
. I only use it on the inverter for about 15 minutes when I take it under my covers with me, knees tented, to warm the cold bed.

Much better to use a 12v mattress heating pad in such a scenario.

And Electric heat is nearly 100% efficient, it just requires a huge amount of electricity produce enough heat to be effective.

Called it.

If you could find a sufficiently inefficient inverter you could use it for a heater and save money.

Might be the best comment in this thread.

 

[highdesertranger]

boy some people didn't pay attention in their physic's class. any time you convert one form of energy into another form there are loses. nothing is 100% efficient. although turning electricity into heat is almost 100% efficient, how many conversion are needed to convert electricity to heat? remember to start at the beginning, first you have to make the electricity(not efficient at all). in our case then you have to store it. then you have to convert it to heat. that's three conversions right there. read this, https://en.wikipedia.org/wiki/Electric_heating . especially the part about environmental and efficiency aspects. and don't say, but I am using solar panels. solar panels are about 20% efficient for turning the energy from the sun into electricity. you would be better off standing in the sun. of course at night there is no sun. so use propane, better yet use body heat. a good sleeping bag goes a long way. highdesertranger

 

[MazdaGuy15]

I am debating putting an electric 110v heat pad like that in the floor of my van. But I would only use it when I was at work where I could plug in. It would be free heat (for me) and help the webasto not run as much.

 

[John61CT]

Free is good, but might as well take better advantage of it. Consider those oil-filled radiators.

At the high end, a water tank brought up very hot will buffer-store the energy all night, no need for anything else. without insulation and controlled circulation to a higher radiator you may be creating a sauna though