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Energy Star

by jalak7
Tags: energy, star
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jalak7
#1
Jan31-13, 02:19 AM
P: 7
My wife and I think two different things, and I would like to see which of us is correct. I'm only somewhat knowledgable of physics, so I may be wrong.

We need an electric heater for a bedroom. My wife says we should be an energy star heater. But I'm saying that it doesn't matter which heater we buy because almost 100% of the electricity used will turn into heat (excluding some tiny amount of electromagnetic radiation). So I think all electric heaters are equally efficient.

Who is right, my wife or myself?
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Crazymechanic
#2
Jan31-13, 02:53 AM
P: 853
Basically your right, electric heating in the most cases use the simple fact that when a current is passing through a resistor it heats up the resistor.
Most heaters use a coil of special metal alloy like nichrome, which has a desirable material durability and electrical resistance to convert the passing current into heat.
I don't think there will or can be much difference in terms of "energy star" for heaters.Ofcourse there are other factors you should look like the safety of the device and rated power.Also thing to check is does the heater rated power suits the one your ac outlet in your room can provide.I assume were not speaking of that big of a heater here but just in case , because sometimes people get like 2kw or more rated big heaters and then use a tiny little power cable to feed them which results in overload of the wire and can result in fire and /or short circuit between the wires.Sometimes the wall outlet gets considerably hot even with smaller power over a longer period of time.Well all you need to do is to pay attention to the ratings of a specific heater.If it says only watts on the datasheet, then divide those watts with your ac mains voltage and you will arrive at the amperage.In ac there are the power factor also to be considered in terms of calculating the real watts to amps but in your case that is not that important as it is a resistive load.

Speaking of energy star it is more used in semiconductor devices like switch mode power supplies , tv sets, and other equipment.
in other words in devices that present non linear (capacitive, inductive,etc) loads to the mains ac.A heaters coil makes a purely resistive load which is the most efficient one in terms of consumed power to output power.
Hope that helps.
Bobbywhy
#3
Jan31-13, 03:24 AM
PF Gold
P: 1,894
jalak7,

You and your wife have the chance to “do your homework” since you have internet access. Safety ought to be your first priority. I suggest you evaluate electrical shock hazards, fire hazards, and burn hazards before choosing your heater. Here are a few websites that can guide your selection of electric space heaters:

http://www.consumerreports.org/cro/space-heaters.htm

http://www.amazon.com/SCI-Resource-P...ews/B004E2XMQE

Picking the right space heater
Various models can deliver warmth, but not necessarily savings
http://www.bostonglobe.com/business/...LrN/story.html

5 Great Portable Electric Space Heaters
http://www.treehugger.com/culture/5-...e-heaters.html

Stay warm, and Cheers,
Bobbywhy

sophiecentaur
#4
Jan31-13, 05:27 AM
Sci Advisor
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Energy Star

When you 'pour heat' into a room, it doesn't always end up making you feel 'cosy'. It's important that the heat gets to you. Radiant heaters can be great against your face but can give you a cold back and cold feet. Fan heaters make a bit of a noise but will heat a room evenly and relatively quickly (for a given power). Convectors under windows will reduce draughts and heat the room evenly and quietly but it takes time.
There is no 'right answer' to this. (You can't beat insulation and draught proofing for long term good value, of course.)
russ_watters
#5
Jan31-13, 05:31 AM
Mentor
P: 22,281
Quote Quote by jalak7 View Post
My wife and I think two different things, and I would like to see which of us is correct. I'm only somewhat knowledgable of physics, so I may be wrong.

We need an electric heater for a bedroom. My wife says we should be an energy star heater. But I'm saying that it doesn't matter which heater we buy because almost 100% of the electricity used will turn into heat (excluding some tiny amount of electromagnetic radiation). So I think all electric heaters are equally efficient.

Who is right, my wife or myself?
You're screwed. Just tell here she's right even though she isn't.
sophiecentaur
#6
Jan31-13, 05:35 AM
Sci Advisor
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Or buy her some warm slippers and a thick dressing gown. Feeling warm is all in the mind - look at Polar Bears, for instance.
Crazymechanic
#7
Jan31-13, 10:22 AM
P: 853
good yoke #sophiecentaur :D Maybe it's because polar bears have the skin and feather as thick as two bulletvests? Or am I just fooled by the illusion of being cold. :D
Ofcourse how you feel has a lot to do with your emotions , oh just by the way speaking of positive imagery for those who haven't seen Dave Chappelles thoughts about it...

http://www.youtube.com/watch?v=WbS9jZOlQjc

:D:D
ModusPwnd
#8
Jan31-13, 10:52 AM
P: 1,062
Quote Quote by jalak7 View Post
But I'm saying that it doesn't matter which heater we buy because almost 100% of the electricity used will turn into heat (excluding some tiny amount of electromagnetic radiation).
Electromagnetic radiation does contribute to the temperature. If you have your thermometer in the shade vs in the light with the same ambient air temperature, one will read higher than the other. Thats because the light contributes to the temperature.

Of course whether you personally are going to feel that temperature is another question, one that was addressed a few posts up.
greswd
#9
Jan31-13, 11:36 AM
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P: 147
just pack your bags and move to the tropics
Crazymechanic
#10
Jan31-13, 11:49 AM
P: 853
Somehow interesting that a thread about household heaters has more responses than an average thread about nuclear physics or electric engineering :D
@greswd moving to the tropics doesn't solve the problem as you would have to use more power to cool your products in the fridge and air conditioning to cool down your head so that you could be able to think and make a meaningful thread or response here on PF.But in that case looks like your already writing from tropics :D:D
just a yoke.no offense.


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