Their colour temperature is likely to be around 3000 to 3100 K. All the electrical energy that goes into a tungsten lamp ends up as heat in a room*, and low-cost lighting units are no different from expensive units in that respect. Work lights would be called 'open-face' lights - they tend to be more efficient than fresnel lights in terms of total usable light per electrical watt, but they are less controllable. They are good for creating large, soft sources by diffusion or reflection, but not so good when used directly.
If you want a ball-park indication of the light output of a 300 W work light, you could look at the performance of the Lowel V-light with a 500 W lamp and reduce to 60%. The V-light is a really simple reflector. For example, at 10 ft you might get around 20 to 25 foot-candles when used directly. That's about f/1.4 at 1/60 and EI 100. Then take a stop or so off for the diffuser, then take two stops off for the 80A filter...
If anyone has actual measurements, they would be better than my WAG.
Best,
Helen
*Well, unless you have living vegetation in the room, of course.
