I really don’t care how many watts it consumes as long as i can keep a stable temperature of 37 degrees C.

**Watts are a measure of energy (heat) and a resistor dissipating 100W will put-out the same amount of heat as a 100W light bulb.**

Power (Watts) = voltage x current

Power = voltage^{2}/R

Power = curren^{2} x R

Of course, the actual *temperature* is not as easy to calculate - A small insulated box will get hotter than a large insulated box. You can’t warm-up a room with a 100W light bulb.

And, you get a certain heat *rise* so without feedback (a thermostat), if the ambient temperature changes by 1 degree, the internal “37 degree” temperature will also change by 1 degree.