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Old 11-19-2010, 10:06 PM   #1
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220v vs 110v Baseboard Heater??


I recently had to replace a baseboard heater. Both the old and new are/where 220v 1000watt units. I also have a portable digital thermostatically controlled baseboard and I got to looking at it and it's 110v 1500watt unit. This got me wondering....

Why would someone want a 220v 1000 watt hardwired unit when you can buy a 110v 1500 watt unit for about the same price and not have to mess with wiring, other than plugging a cord into an outlet. Something has to give! Some might argue the hardwired unit is safer, but my old one shorted out and I got very lucky it didn't burn my house down, whereas the portable one has all sort of safety devices built in and if it would have shorted, would have likely tripped a breaker whereas the 220v unit didn't.

I realize that when it comes to electric motors 220v motors tend to be more powerful, run cooler and last longer, but when dealing with a fairly simple heating element what gives???

Can someone please explain this to me?

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Old 11-19-2010, 10:29 PM   #2
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220v vs 110v Baseboard Heater??


Your hardwired one didn't "short" and not trip the breaker unless you have Federal Pacific or Zinsco breakers. A true "dead short" will trip a breaker, hardwired or not.

I'm gonna tweak both of your numbers. I'm going to make them both 1200 watts, because it makes my math easier, and I'm really tired and lazy right now, so easy is an important factor.

1200 watts at 120 volts is 10 amps. 1200 watts at 240 volts is 5 amps.

Now heat a large room with those. The livingroom in the apartment complex I grew up in had about three times that wattage for heaters. at 240V, that's 15A. We can wire up the whole 3.6kW of heaters with a piece of 12/2. At 120V, that's 30A. We now need 10/2, which is heavier wire, harder to work with, and more expensive.

3600 watts at 120V is adding 30A load to one 'leg'. You've always got some resistance in every conductor, so there's a fair chance that the voltage drop in the neutral will be noticeable, so you'll actually have a slight INCREASE in voltage in the other leg. Not enough to damage anything, but you may very well notice lights brightening/dimming as the heater cycles on/off.



NOW, that's the 240 vs 120 argument. Hardwired vs Portable, that one's easier.



No idea what the load on this receptacle was, but it was about the third one in a string totalling seven. I got this job because five receptacles (including this one) at random locations in the house didn't work. The most common failure point in an electrical system is not the middle of a piece of wire. It's almost always where something connects to something else. What's more reliable? Breaker -> Thermostat -> Heater, or Breaker -> Receptacle -> Receptacle -> JunctionBox -> Receptacle -> Wirenut buried in a switchbox -> Receptacle -> Receptacle -> Crimp connector buried above a ceiling light -> Receptacle -> Heater?

Let's not forget that those various connection points are also where heat is created, and if you're going to have a fire, it's going to start in one of those spots.

AND! :D (back on the 240/120 thing)

Continuous loads (which heaters are) are limited to 80% of a circuit's rating. Thus a 20A circuit can only power (see you're making me do math now!) 16 amps or 1920 watts worth of heat... and that heater is going to have to have one of those "Dangit why is this blade SIDEWAYS?!" weirdo 20A plugs. A 15A receptacle (even one wired to a 20A circuit) is limited to 12A or 1440W. They get the "1500W" label either by rounding or by claiming the wattage at 125V rather than 120V. Considering voltage drop that IS going to happen with a 12A load, the only way you're getting 125V at the receptacle while that heater is in use is if you're starting at something like 130, which is frying a bunch of other stuff in your house...



Frankly, I'll stick with oil- or gas-fired hydronic baseboard

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Old 11-19-2010, 10:38 PM   #3
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220v vs 110v Baseboard Heater??


Power = Voltage x Current. You do the math and figure out what size wire is needed for the two heaters. Then remember that you would have cords all over the place.
I will have baseboard heaters in my new house and they will be on their own meter and get a much lower rate than I would get if I use 120 volt heaters plugged into a standard outlet.
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Old 11-19-2010, 10:45 PM   #4
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220v vs 110v Baseboard Heater??


Ok, I appreaciate your response and it does cover some of the safety aspects, but I was told that what my baseboard did was short to ground. It was on a single pole thermostat, new one is a double pole with positive off, hoping safer. In essence what happened is that the coil had an issue and broke/melted, it singed the carpet and thus wasn't very safe. I didn't notice the problem right away, but noticed even with thermostat to what I thought was off, it was still heating so I flipped the breaker off not wanting it to get to 80+ degrees in the room.

I am still curious why the 220 is better. Like I said the 220 states 1000 watts, the 110 states 1500. Even if those are fudged a bit, wouldn't the 110v 1500w heater put out more heat? Granted it would cost more being more watts. Is the 220v unit somehow cheaper to operate??

Thanks again.
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Old 11-19-2010, 10:56 PM   #5
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220v vs 110v Baseboard Heater??


I saw that thread, where the element... shortened itself. It obviously didn't draw enough current in doing so to trip the breaker.

The same thing in the 1500W 120V unit wouldn't trip a breaker either.

You can argue that it would - and the only reason is because the heater is so close to the circuit's maximum rating already that ANY increase in current will bring it over the limit. A 1500W 240V unit with a 7.5A breaker (stop laughing) or a 3kW 240V unit on a 15A breaker would similarly be "at the limit". However, it is not realistic to conclude that "running circuits at or very near their functional limitations is safer" and I trust that you would not insinuate this.

All the various safety devices on the portable heaters are usually based on making sure the heater doesn't get tipped over, or overheat due to lack of airflow. Some do have built-in circuit breakers, I suppose, but I haven't seen very many. You are correct that permanently-installed baseboards don't have as many fancy controls attached to them. I'd like to see you "tip over" a heater that's bolted to the wall. Many of them DO have means to prevent overheating.



Also, and I say this based on my "other career" of appliance repair: all those fancy controls aren't as well-built and genius-engineered as you think. The last one I tore open (to replace the power cord) had all manner of fancy blinky lights and buttons, but was internally a couple of simple on/off rocker switches, mechanical thermostat, and one "thermal circuit breaker" (funny little black thing with two terminals, that opens the circuit if a certain temperature is exceeded). This was one of those "oil-filled radiator" ones with no tip protection. Your hardwired baseboard doesn't need either of those first two - the switch and thermostat are in one unit on the wall somewhere, and many of them have almost exactly the same thermal circuit cutout.



Through all of this, the ONLY "portable heaters are better" safety argument I can personally agree with is that, if a portable heater catches fire, it's easier to pick it up and throw it out the window than it is to do the same with a unit that's bolted to the wall :D
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Old 11-19-2010, 10:57 PM   #6
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220v vs 110v Baseboard Heater??


Wire size isn't/wasn't an issue. I was told the 220v unit could be wired on 14/2, it's wired on 12/2 with a 20amp breaker. The portable is a 15amp unit, so when used it's on a 15amp or 20amp circuit and never tripped either.

I guess I'm just curious why they make the 1000w hardwired units 220v when the 1500w portable units are 110v. I'm starting to think by some of the responses, it's because people daisy chain them together and that would make sense. Am I correct in thinking that 1500w is 1500w no matter if it's 110v or 220v and that the heat will be the same as will the electrical useage?
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Old 11-19-2010, 11:02 PM   #7
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220v vs 110v Baseboard Heater??


Every time I respond tonight I look back and realize I missed something.

1500W is more than 1000W yes. It is not fair to compare their heat output. Obviously 1500W (1440W on 120V) is more than 1000W.

If you want to compare them that way, let's go buy a 1500W 120V heater and a 1500W 240V heater. Now *I* get to do something unfair with numbers. The 1500W 120 unit is actually 1500W on 125V, and 1440W on 120, because 1500W through a 15A plug is illegal. The 1500W on 240V is truly 1500W, so my 240 unit gets an extra 60 watts of heat

Even looking at that "fair", it may still be true. 10A through your house wiring (and umpteen dozen other receptacles and wirenuts buried in stupid locations) will be subject to a much more significant voltage drop (remember, the wires and connections have resistance) than 5A through less wire.



Regarding the "more economical to run" question... uhh... this is a funny area. Electrical resistance heating is one of the few areas where we can argue that the whole unit, either way, is 100% efficient. All the energy "wasted" comes out of the wires as heat. Since we assume the wires are in your house, the wasted energy still heats your house, which is the goal...

If somehow the wasted energy doesn't get into the room you're trying to heat, however, then yes, at 120V you're losing more energy to resistance (and thus voltage drop) in the wiring.
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Old 11-19-2010, 11:04 PM   #8
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220v vs 110v Baseboard Heater??


"daisy chaining" is a big part of it, yes...

but, plain and simple, given two identical (power/wattage rating) loads, the 240V variant will pull less current, allowing smaller wire (OR wasting less energy in voltage drop on the same size wire), cause less "localized heating" (hot spots at connection points), and cause less strain on components (due to the localized heating thing). That's why large loads (including the motors you referenced) are usually 240V.
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Old 11-19-2010, 11:13 PM   #9
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220v vs 110v Baseboard Heater??


Quote:
Originally Posted by Master Brian View Post
Wire size isn't/wasn't an issue. I was told the 220v unit could be wired on 14/2, it's wired on 12/2 with a 20amp breaker. The portable is a 15amp unit, so when used it's on a 15amp or 20amp circuit and never tripped either.

I guess I'm just curious why they make the 1000w hardwired units 220v when the 1500w portable units are 110v. I'm starting to think by some of the responses, it's because people daisy chain them together and that would make sense. Am I correct in thinking that 1500w is 1500w no matter if it's 110v or 220v and that the heat will be the same as will the electrical useage?
Run your portable heater for an hour and then feel the wire feeding it.
You are correct in that 1500 watts is 1500 watts but it takes 1/2 the currant at 240 vs 120


Last edited by a7ecorsair; 11-19-2010 at 11:15 PM. Reason: Added additonal information
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