TV Heat Output.. Plasma VS LCD VS LED VS DLP  

I voted for led but I do not mean to imply that an lcd is going to produce significant heat (it wont). My pdps do produce more but not enough to stop me from buying one (I am in the northeast so I only have 3 months of hot weather and it is not a problem). Doesn't everyone in SF have AC?

The LED lit LCDs will have less heat output than the same size CCFL LCD. The equivalent plasma will put out slightly more heat than the CCFL LCD.

It's no contest. (led)

FWIW, my DLP front projector doubles as a space heater in winter.

I have a LED and LCD sitting here in my family room (trying to decide which one to keep) and the LCD is significantly warmer. The LED runs pretty cool actually, and has better energy efficiency.

If this poll is supposed to accurate it is way wrong, you don't even have the categories correct, and you left out a couple...

1. LCD-CCFL
2. LCD-LED Edge-Lit
3. LCD-LED back-lit
4. plasma
5. DLP
6. DLP-Laservue
7. CRT
8. OLED

So's your grammar....

What? That makes absolutely no sense what you just posted.

oh and PERIOD!

Big Mac you are the one who is wrong! Please read THOROUGHLY the poll and then apologize for thinking us pdp owners are incapable of providing quality, thorough and informative information and voting.

And you know what??? Since BigMac did not read the poll correctly and only 1 person voted for plasma (I assume him since he read it wrong) it PROVES exactly the opposite of what he accused us of. lol

Call me when someone can show that heat output isn't largely correlated with power used. (Note that the preceding sentence has the word largely in it.)

Whats your point? The OP asked about heat output not power used and no one stated anything about power used. Did you pick that out of thin air?

Oh and pellet stove, the sun, my 97% efficient gas heat and halogen lighting vs incandescent to name a few.

I stand corrected! I was wrong! Tail tucked! but sorry!

Peace - Big Mac. Everyone makes mistakes. Just having fun with it. Was I right you are the lone plasma voter? lol

I currently own a 2010 54" Plasma, a 2010 60" Edge lit LED-LCD and recently sold a 2008 52" CCFL-LCD. The displays have been calibrated using the Spears and Munsil BD so they are/were pretty close to the same brightness. The heat output from lowest to highest is LED-LCD, CCFL-LCD then Plasma. Which not surprisingly is directly correlated to the energy consumed. The LED draws ~110 watts, the CCFL ~150 watts and the Plasma ~300 watts during normal cable TV viewing. The larger LED draws less power than the smaller CCFL and significantly less than the smaller Plasma. The vast majority of power consumed by a display will be dumped into the room as heat. If heat is a major concern for you I would recommend looking at the LED-LCD's. I don't think they can beat for energy consumption at this point.

All of the power consumed will be dumped into the room as heat. The tiny amount radiated as light will also convert into heat.

Tiny or not, all power into the set turns into heat in the room.

this input was provided:


The first law of thermodynamics basically says that energy is neither created nor destroyed. It just changes from one form to another. One form of energy is heat, which can be generated by various means. In the case of electrical appliances it is generated by many solid state devices, chips, mechanical devices and so on. That's why some electronics have cooling fans (just look in your computer). The power that an appliance such as a TV requires is not all used to produce heat. Some of it may be used to run fans, light LEDs or fluorescent displays, etc. The power simply is changed from one form to another to make it all work. The amount of power that goes in does not simply equal the amount of heat the is generated by the appliance. Some of the energy produces the picture you're watching. Some also produces the sound you're listening to.

Thank you for posting this - the geek in me was getting antsy reading some of the previous comments about everything ending up as heat...

To piggy back on previous comments made regarding efficiency - any device's efficiency is measured by how well it converts input energy to the desired form of output energy. Heat is not always a waste product - in the case of a furnace or the sun, it is a desirable form of output energy. For a display device, a device that can produce the most unit light (and possibly sound) per unit of electricity consumed is the "most" efficient. In this case heat is an undesired form of energy emitted by the display, but simply measuring heat output without looking at electrical input and light output does not tell the whole story. Obviously LED is significantly more efficient than plasma, but as I always say there is no such thing as a free lunch.

I actually think my original comment stands up well.

My claim that "all power into the set turns into heat in the room" is correct, almost. The quoted statement above is correct without any disclaimers. The subtle difference between the two claims is highlighted.

The power that goes into a TV set turns immediately into heat in the resistive elements of the set when current flows through them. Majority of this energy escapes the set as hot air by convection, while a much smaller amount is conducted.

Another form of energy leaving the set is the screen light radiation. This form energy will hit the targets such as the walls, people, pictures, etc. where it will be absorbed and turned into heat. A small part will be reflected and bounce around until eventually it is all aborbed and turned into heat.

Another form of energy leaving the set is the sound. As above, it will turn into heat by causing vibrations in the walls and other lossy objects.

Another form of energy leaving the set is RF radiation. The FCC regulations require that it be less than the allowed limits but it is not zero. This energy will, just like in a microwave oven, turn into heat.

With all that energy getting into the room, without the exactly equal amount escaping, the room temperature would reach infinity and everybody in it would die. Luckily, the elevated temperature in the room causes the energy to be transferred to the rest of the house and, eventually, into the air outside.

The same applies to the three other forms of energy I listed. Some sound escapes and we hear what our friends next door are playing. If there are windows, some light energy escapes through them. In that sense, my claim is not 100% correct as it does not, for simplicity, account for these three forms of energy escaping the room. Whatever will fail to escape, will turn into heat.

Admittedly, the direct heat generated by the resistive elements in the set accounts for most of the input energy so that the other three are mentioned just for the record as an exercise in hair splitting.

No, a microwave oven works only on water, and for a specific reason. All energy does NOT "turn into heat" as you claim, which flies in the face of very basic physics.

In "very basic physics", energy can neither be created nor destroyed, only changed in form. In a microwave over, very basic physics take electricity -- energy in the form of electrons -- and use it to excite mostly water for the purpose of heating the underlying food. So, like, you know... the energy does turn into heat, albeit through a convoluted process where the electrical energy is radiated via a magnetron to excited water molecules.

When did I say energy was created or destroyed?

A microwave oven works only on water because it emits electromagnetic energy with a frequency that matches a fundamental harmonic frequency of water. Put a piece of cardboard or glass in a microwave, and neither will get hotter. Where does all that electromagnetic energy go? Nothing is getting hotter. Answer that question and you'll understand my point - there is a fundamental difference between molecular vibrational energy (heat) and electromagnetic energy, although the two are somewhat related. The latter doesn't simply turn into the former. Very basic physics.

I agree! The statement was very accurate. My comments are that by writing it you started the whole change in thread focus from heat output associated with the display technology into the correlation of heat output to to power consumed. I don't say your post is inaccurate at all (Its accurate) except it was not on the topic.

The first law of thermodynamics is that the change in internal energy is equal to the heat added TO the system MINUS the work done BY the system. What Mark wrote I believe is the Principle of Conservation of Energy not the first law of thermodynamics (which certainly does follow the CoE principle). If it was used to show not all power consumed = heat then 100% correct. However it should not be used to support that the display tech does not determine the heat output. In analyzing different display technologies the tuners, speakers, and associated circuits are largely going to cancel each other out. What it comes down to is what each display tech uses in power to produce the picture (the work) and its associated heat output. And now we are back to exactly what the poll asked.

Here is the face of very basic physics. From Wikipedia:

A microwave oven works by passing non-ionizing microwave radiation, usually at a frequency of 2.45 gigahertz (GHz)a wavelength of 122 millimetres (4.80 in)through the food. Microwave radiation is between common radio and infrared frequencies. Water, fat, and other substances in the food absorb energy from the microwaves in a process called dielectric heating.

Microwave heating is more efficient on liquid water (than on frozen water, where the molecules are not free to rotate) and on fats and sugars (which have a smaller molecular dipole moment).[8] Microwave heating is sometimes explained as a resonance of water molecules, but this is incorrect: such resonance only occurs in water vapor at much higher frequencies, at about 20 GHz.[9] Moreover, large industrial/commercial microwave ovens operating at the common large industrial-oven microwave heating frequency of 915 MHzwavelength 328 millimetres (12.9 in)also heat water and food perfectly well.[10]

Microwave heating can cause localized thermal runaways in some materials with low thermal conductivity, where dielectric constant increases with temperature. Under certain conditions, glass can exhibit thermal runaway in a microwave to the point of melting.

The question is whether or not heat generated by 2011 build ccfl LCd, led LCd, dlp or Plasma's is a problem in a 12x12 room in Florida.

That question can be answered by bringing into the room a lamp and two bulb, one 150W and another 300W, to simulate an LCD and a plasma. As the average human body dissipates about 100W doing nothing, the test should require that the person or persons be there during the test. As watching a lamp glow is not very intellectually stimulating, a good book would be helpful.

The problem is with defining the "problem". This is so subjective nobody can answer this but the OP himself so coming here with a question like this is a waste of time.

He has not only a legit question but also the right to come into the forum and ask the question. If it's a waste of time for you then maybe you can move on to something else.

To the OP, all sets will put out some heat but in order of least to most I would rank it as LED, LCD and then plasma. The difference varies between each type and none of the sets are actually heaters and will depend on the room configuration as to how well the room and the set dissipates any heat build up. It will also depend on what else will be on in the room as set top boxes, AVRs and computers can generate a fair amount of heat adding to the issue.

He did not ask if any of them would be a problem. He asked which tech produces the least amount of heat so that he minimizes his chances of a problem (really none of them would likely be a problem). Its certainly is a legitimate question to ask. Not so long ago I would have said DLP (around .1 to .2 wsi) with lcd close. Now with led (many <.1 wsi) it has changed (IMO).