Need Help with DIY Electric Heater, 120vac, 1000 watts

Thread Starter

Guest3123

Joined Oct 28, 2014
404
I need to make a decent heater to heat my room upstairs. 7.83' (W) x 22.83' (L) x 6.875' (H), but the ceiling is slanted, so it's less.

I'm serious. I'm suffering up here. It's now 54° F, and it's cold. The Space heater(s) I've tried don't do jack. I'm fluent with Resistance wire like Kanthal A1 Resistance wire, etc. I was thinking of using mains electricity, and doing something like a wood frame, with stainless steel eye hooks or bolts.

My room upstairs is wired for 15 amps, 120vac.

If I did 1000 Watts, that's 120 (117.0vac), 8.54A, 13.7Ω

So I spent the last 2 hours making a piece of software that will calculate everything for me. It calculates the the length in Millimeters, Inches or Feet, for NiChrome 80, NiChrome 60, Kanthal A1, and even Copper Wire. But I wont be using Copper wire. duh.

Put a brand new lasko 20" box fan in the wood frame, behind the wires, or coils, and blow air threw the coils or wires to produce warm forced air into the room.

I think my heater will work best, and better than the crappy 1,500 watt space heater, that does JACK.

Can someone help me.. I would like to know if my configuration will work. I also know that I might have to use extension springs because the wire expands as it heats up. etc.
 

#12

Joined Nov 30, 2010
18,167
If I did 1000 Watts,
I think my heater will work best, and better than the crappy 1,500 watt space heater
It seems that simple math isn't working here.
Either your heater is broken or you have dreadful insulation.
I recommend you direct your attention to the obvious, unless designing less heater than you already have keeps your brain warm.;)
 

Hypatia's Protege

Joined Mar 1, 2015
3,203
If, as you say, 1.5kW is insufficient, what makes you think 1kW will suffice?:confused::confused::confused:

Best regards
HP

PS -- My advice, FWIW, Is that you purchase a 2kW baseboard heater and call it good!:) --- Of course anything above 1.8kW (as a practical matter >1.6kW) is best realized via a full secondary (i.e. 240V) connection...
 
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Thread Starter

Guest3123

Joined Oct 28, 2014
404
If, as you say, 1.5kW is insufficient, what makes you think 1kW will suffice?:confused::confused::confused:

Best regards
HP

PS -- My advice, FWIW, Is that you purchase a 2kW baseboard heater and call it good!:)
I honestly don't know what else to do. I can't fix the walls, or the poor insulated walls in this old victorian house with lathe and plaster walls.. I thought that maybe a wider surface area, more heated surface, and bigger fan would work better. You should see this little heater.. It's plastic and very small..

I have a feeling it would work better. Design and execution means a lot in electronics. Why do two things that put out the same amount of power perform better than the other? Or why does the forced hot air heater work better than a radiant heater? But they're both 1,500 watts..?

Or why does a resistor that draws 1,500 watts do squat compared to a radiant heater?

It's the design. It's the way it's built and designed. If you agree or disagree, I'd like some feedback.
 

Hypatia's Protege

Joined Mar 1, 2015
3,203
Why do two things that put out the same amount of power perform better than the other?
They don't where electrical (or otherwise non-vented) space heating is concerned! -- Note that 'heat' is thermal physical entropy, thus 1.5kW energy in = 1.5kW heat out!:cool: -- Granted! A 100% efficient design will be non-forced (e.g. convective or radiant) operating at "sub incandescent" element temps (hence all input energy is converted to 'heat' both directly and via FIR, etc...) as a practical matter, however, the few watts required to operate a blower plus the few milliwatts lost as visible light from an incandescent element are negligible...

Or why does a resistor that draws 1,500 watts do squat compared to a radiant heater?
It's a matter of what you wish to heat -- Radiant heaters heat certain objects (as, for instance, humans) far better than air --- So, what's good for comfort may not be good for plumbing:cool:

Source --- I hail from Minnesota!:eek::D

Best regards
HP

--Edit to correct appalling word choice--
 
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Hypatia's Protege

Joined Mar 1, 2015
3,203
Here's a thought -- If you wish to 'do' radiant heat 'on the cheap' note that two 'brooder lamps' will provide 1.2kW for less than $20.00 total:)

Best regards
HP

EDIT -- Seems the 600W bulbs aren't as easily sourced as in years past -- still... I think you get my point...:cool:
 
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BReeves

Joined Nov 24, 2012
410
Get 220 up there even if you have to run conduit up an outside wall and get one of these.
http://www.northerntool.com/shop/tools/product_200452347_200452347
I have one like it in a 20 X 40 out building. Takes a couple hours to warm the building if I start it when the building is really cold (20+-) but once it's warm it will it will keep it warm and toasty.

Or at least get a real space heater, those little ceramic space heaters are for warming your feet under a desk and are basically junk.
http://www.northerntool.com/shop/tools/product_200631840_200631840
Just be careful with it, many house fires are caused by space heaters running on poor wiring.

Best would be option #1 as you would know the wiring is good and you could leave it on without fear of a fire.
 

mcgyvr

Joined Oct 15, 2009
5,394
You are SOL...
As stated you need to reduce heat loss or increase heating wattage..
neither seem to be doable by you.. put on a sweater :)

maybe look into passive solar heating.. (its FREE) and can really make a big difference..
 

#12

Joined Nov 30, 2010
18,167
HP You can ease your tautology phobia by just saying heat is _physical_ entropy:p!
Or you could get really simple and say it something like this: All small heaters are basically the same as each other. That includes resistors. Heat works according to simple math. Every watt hour of power converts to 3.413 B.T.U.s of heat. Even if the energy comes out of the heater as light, it turns into heat when objects in the room absorb the light.

The severe limit I see here is a 15 amp power line. 179 square feet of room isn't usually this hard to heat, but the shape is worse than most. Long side 3X the short side, and I'll bet the long side is facing the weather.:( This shape requires a fan to distribute heated air, but the radiant heater method looks interesting to me. If you can be 20 feet away from the radiator and feel the warmth, that's about as good as a fan, but I can't remember any heater I could feel 20 feet away. You can cut that to 10 feet by placing two heaters in the center of the room and face one each way. Those 600 watt brooder lamps are looking better all the time!

With a design limit of 12 amps (according to the National Electric Code) your power limit is 1440 watts...less than 4000 B.T.U.s per hour. That's less energy than we use for air conditioning in Florida. You are either going to have to heat the person, not the room, or insulate better, or bring more power (with better electric service).

That's the math of it.
 
Or you could get really simple and say it something like this: All small heaters are basically the same as each other.
I hear you! -- That said, I feel that reference to underlying principles provides 'inline' sourcing, and, hence, a more comprehensive reply -- Moreover I can't seem to manage 'really simple' without coming off as condescending:oops::(

but the shape is worse than most.
Indeed! - I'm guessing it is a repurposed corridor?:confused:
The severe limit I see here is a 15 amp power line. 179 square feet of room isn't usually this hard to heat, but the shape is worse than most. Long side 3X the short side, and I'll bet the long side is facing the weather.:( This shape requires a fan to distribute heated air, but the radiant heater method looks interesting to me. If you can be 20 feet away from the radiator and feel the warmth, that's about as good as a fan, but I can't remember any heater I could feel 20 feet away. You can cut that to 10 feet by placing two heaters in the center of the room and face one each way. Those 600 watt brooder lamps are looking better all the time!

With a design limit of 12 amps (according to the National Electric Code) your power limit is 1440 watts...less than 4000 B.T.U.s per hour. That's less energy than we use for air conditioning in Florida. You are either going to have to heat the person, not the room, or insulate better, or bring more power (with better electric service).

That's the math of it.
Agreed!:cool:

Best regards
HP:)
 
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AnalogKid

Joined Aug 1, 2013
8,251
There is n.o.t.h.i.n.g you can build that will work as well and be as safe as something from Wal-Mart. Ceramic, oil, suspended nichrome - whatever. Watts is watts, and 1500 of them are more than enough for 1230 cu.ft., especially with such a low ceiling. Fan size is important. Too small, and the heat does not distribute throughout the space. But heat is lost through turbulent contact with the walls, so an oversized fan increases the rate of heat loss.

ak
 

tcmtech

Joined Nov 4, 2013
2,868
So why not just run and extension cord from another rom that is on a different circuit and have two heaters going?

Or is there something about this that is too obvious for me to catch? o_O
 
So why not just run and extension cord from another rom that is on a different circuit and have two heaters going?

Or is there something about this that is too obvious for me to catch? o_O
Or... Derive 240V via connection to two receptacles which being on opposite sides of the distribution transformer's secondary? (I'm guessing the NEC would be averse?:eek:)
 
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