I get tired of seeing all the advertisements during the winter season about how much money you are going to save with some new electric heater gimmick.
By definition, All electric Heaters are 100% efficient. Power comes into the heater and 100% or it is converted to heat. It's as simple as that.
The only possible gimmick that the marketing people can use is to vary the ratio of radiant and convective heat. The radiant will make you feel warmer if you stand in front of it, but you don't need a fancy oil filled or ceramic heater to do that. Any heater that has a glowing element will produce the radiant heat.
Gonna have to call BS on this one Perry, if you compare a old school baseboard electric heater to a modern porcelin electric heater then you will find a huge difference in efficiency and operating cost.
I'm siding with Perry here. If you have two identical rooms and heat them to the same air temperature using any two electric heaters similarly placed, the cost will be the same. Radiant heat may make one feel more comfortable than the other.
conservation of energy
> Gonna have to call BS on this one Perry, if you compare a old school baseboard electric heater to a modern porcelin electric heater then you will find a huge difference in efficiency and operating cost.
Boundary,
Both the old school baseboard and the modern porcelain electric heaters are 100% efficient. All the electricity gets converted to heat. There is no where else for the energy to go.
conservation of energy
http://en.wikipedia.org/wiki/Annual_fuel_utilization_efficiency
conservation of energy
> if you compare a old school baseboard electric heater to a modern porcelin electric heater then you will find a huge difference in efficiency and operating cost.
I would guess that many baseboard heaters were installed adjacent to poorly (or un-) insulated walls and floors, resulting in a significant heat loss to the outside. That may account for the perception that baseboard electric heaters are not very efficient.
conservation of energy
Amps in, resistance then heat. It is the conversion from the heat produced, by whatever resistance is used, to useful energy that counts. None are 100 efficient in converting the energy used into useful heat.
jud
conservation of energy
So where in this case does any heat or other energy go that isn't useful?
The comment about wall insulation was good, but it only makes a difference between heaters if somehow the wall leaks more heat from one kind than the other kind. If you put the heater against a poorly insulated wall it doesn't make much difference what kind of heater it is.
Allright. I'll bite. How much electricity (dollars) did it take to produce the same radiant heat from the old ones versus the new ones? 🙂
Perry is 99.95 percent correct. There are very minor differences between two electric heaters, efficiency-wise. A current is passed across a signficant resistor which, by design, converts it nearly 100 percent to heat energy. That heat moves away from the reistor via convection and radiation. The radiative effect is somewhat minor as it a function of the fourth power of the absolute temperature of the surface of the resistance compared to the fourth power of the absolute temperature of the surface of the receiving entity (wall, floor, ceiling). The differential in these two numbers would be nearly identical regardless of heater design. The convective effect is dependent on the velocity of a forced air stream passing the resistor. The electrical efficiency of the propulion device would have a minor impact on overall energy effeciency as the ineffeciency of the propulsion device is also heat energy.
Think about it. What other form of energy, except heat, is being created by the passing of the current through the resistor?
conservation of energy
> Amps in, resistance then heat. It is the conversion from the heat produced, by whatever resistance is used, to useful energy that counts. None are 100 efficient in converting the energy used into useful heat.
> jud
They are all 100% efficient. there is no other for the energy to go other than into heat.
What is confusing everyone is that.... Usually heat is a waste product. The reason an internal combustion engine is only 25% efficient is mostly because of heat loss.
Geez, what did you major in at Cow School?
It definitely wasn't cud chewing.
I'm impressed.
Seriously.
Don
> Geez, what did you major in at Cow School?
> It definitely wasn't cud chewing.
> I'm impressed.
> Seriously.
>
> Don
Don,
Holy over-complicates the issue. First, the resistor turns all the electrical energy into heat and second; any energy that goes into a fan, also gets totally converted to heat.
It doesn't matter whether it's a 1000 watt heater, a string of light bulbs that uses 1000 watts of a bunch of tv sets that use 1000 watts. They will all put out exactly the same amount of heat.
Your title assumes that heaters are all the same and converting electricity to heat is all they do, but that fails to recognize they may have different heat delivery systems. Some heaters are more efficient at spreading the heat around, such as one may have a fan and one may not, or a better design than another like a thermostat which is something else that can make one heater more efficient than another one...
Also, considering I once owned a brick house with plenty of insulation and its only heat source was baseboard strip heaters in each room and even though it never made the house overly warm it was producing power bills to the tune of $400 to $500 per month vs. I can run two of these little ceramic heaters non stop and it will burn you out of the room and not punch up my electric bill to much at all.
While you may be mostly correct on the energy conversion theory your title is directed at the term "heaters" and I am still gonna have to call bs on the claim in the title.
Perry
Turning the fan uses energy. It is not available as heat.
Engineering, with a few simple little classes like physics, thermodynamics, electronic circuits and controls, a graduate level course in environmental engineering (heating, cooling and ventilating equipment) and a graduate level course in heat transfer.
>Turning the fan uses energy. It is not available as heat.
Using the energy means it was turned from electrical to some other form of energy. Conservation law - it doesn't go away. Every use of energy ends up turning it into heat in the end if you follow it through all the conversions to various forms.
In the fan, the conversions include heat in the motor and motion in the air. Even the air motion eventually turns into heat as the air molecules experience turbulence and have collisions. So that heat still stays in the room.
The only form of energy that might theoretically escape this room is electromagnetic, including light. The infrared and visible light from a glowing heater that gets out a window carries a negligibly small amount of energy that turns into heat outside. So do the electrical and magnetic fields of the alternating current, a tiny fraction of which will escape the room and turn into heat outside. These effects are below the least significant digit of the electrical power you can measure coming into the room.
The most practical difference between heaters (besides comfort due to radiated heat) as it affects the air temperature might be where they are placed. If one heats up a poorly insulated wall more than another heater, then there will be more loss through the wall.
Where you can really save money with a small electric heater is by just heating the room, or even the space around you, rather than the whole house. Twice in my life I have lived in homes with wall resistance electric heaters in each room. Typically listed as the highest cost heat you can have. In fact, if you are diligent to just heat the rooms you are in, when you are using it, this is the cheaptest way to heat a house.
A fantastic way to save tons of energy is to get a programmable thermostat, keep it at 63 during the day, 59 at night, and get a mattress heating pad.
Well said Bill!
yes, the energy powering the fan also turns into heat.
