On Tuesday 08 March 2005 11:48, Gene Heskett wrote: > It is essentially and for all measurement purposes free if the rest of > the house is also electrically heated also. Heat is heat, and the > rest of the house isn't going to give a flip what it is that > generates the calorie's to make up for the insulation and cold air > insolation losses. To maintain 68F on a -10F day is gonna take x > turns of the wheel in the meter, no more, no less. First of all it is not unimportant how the heat is produced. The effect might not be very big however. But it is important how good the heater is to distribute the heat produced. If the heat is not well distributed you create hot spots. If these hot spots are close to outer walls, ceiling or floor it causes a larger heat loss out of your house than if the heat is well distributed in the house. In modern house design insulation and heaters are optimized to minimize such effects. Your computer an the other hand is located in the place where it is most convenient and with no consideration to effective heating of the house. Second, a large development of heat in your computer may create surfaces with a temperature in excess of 50C. At this temperature a significant part of the electromagnetic (black body) radiation will be inside the spectrum where normal windows are transparent, and if the radiation can reach the windows it will increase the heat loss. Third, thermal heat is a major byproduct of almost all means of producing electricity. In many countries all but the most shallow populated areas are connected with heat pipes from the power plants to utilize the heat produced there. Still however all the heat produced can not be utilized because the need for electricity greatly exceeds the equivalent need for heat. Thus when you choose to let you computer heat your house you're creating a double loss. The equivalent amount of heat produced at the power plant is wasted, and more electricity needs to be produced together with more useless heat. In a medium effective goal plant the surplus heat is approximately 60% of the energy developed from burning the goal. And in no case that I'm aware of do the pure electricity efficiency exceed 50%. Forth, other efficient means of heating the house exist that do not involve production of electricity. These involve heat pumps, direct solar heating and others. Again using you computer as a heater is double loss. Fifth, in many places the energy need for cooling exceeds the need for heating. Here using the computer as a heater, the loss is manyfold. Finally, in state of the art residence houses in eg. Scandinavia, there is almost no external supply of energy for heating nor for cooling. These houses have a highly optimized design to balance to intake of energy during summer and store it in reservoirs in the construction materials. From here the heat is released during the winter eliminating the need of external heating. Still such house are very expensive to build and still not very common. However in the future we'll have to realize that any energy consumed for other than its primary purpose is a waste. Regards Torben
