Svar:
Som Du säger är det klart att all värme i det värmebärande mediet inne i elementet "går ut" i rummet. Verkningsgraden är alltså 100% för båda. Men det finns flera skillnader. Fördelen med olja är att det blir en jämnare uppvärmning och ökad säkerhet, se nedanstående svar från länk 1.

Tillägg 2011-12-31

I assume you mean by "oil radiator" an oil filled radiator, these are like a central heating radiator, but filled with oil with an electric heating element incorporated. This heats the oil which circulates by convection within the radiator giving a fairly even surface temperature. So both the appliances you mention are heated by electricity. With few exceptions, electrical heaters operate at 100% efficiency. You put 1kW of energy in and you get 1kW of energy in the form of heat out. So no difference there. As someone has said, an oil filled radiator takes longer to cool down when turned off, but takes longer to heat up when turned on whereas an electric fire has a more immediate response, so again no difference in energy use there. An oil filled radiator however has two main advantages over an electric fire. It would be safer to use in an attic as there is no exposed hot element to cause a fire if positioned near combustible materials and most come with a built in thermostat to allow the heat ouput to be controlled, so I would go for the radiator.

There is another form of electric heater which would have a small running cost advantage over the above. This is a radiant heater, which will warm you rather than the surrounding air, but I would only consider these viable for difficult heating applications such as churches, factories etc with high ceiling heights. They can be quite difficult to position effectively in rooms with normal ceiling heights, but are ok for smaller rooms such as bathrooms.

Chartered Building Services Engineer

Som en läsare påpekat (tack Karin L!) är inte oljefyllda element mer effektiva, utan det viktiga är att ha en bra termostat.

Observera att vi talar om fristående eluppvärmda radiatorer. Om man kan välja är naturligtvis ett system med en central värmekälla och vatten som värmebärare mycket bättre eftersom det ger en flexibilitet vad gäller värmekälla (t.ex. elpatron, olja, värmepump).

Se även länk 2.
/Peter E

Nyckelord: värmeöverföring/transport [46];

1 http://uk.answers.yahoo.com/question/index?qid=20080103072012AAjiIUi
2 http://energimyndigheten.se/sv/hushall/Din-uppvarmning/Elvarme/