OK, not known is what stage your bleed air is taken from. In most jet engines that operate at high altitudes take their bleed air from two different points. A low pressure source where the temperature is approximately 250 degrees. The high pressure bleed valve temperature is approximately 600 degrees. There is some type of mixing valve that uses both to maintain a pre-described duct pressure and as a safety also monitors pack temperatures.
Now in a helo, you do not need the high pressure so i am assuming you have one stage of bleed air source. I am betting that the temperature is somewhere between 250 and 300 degrees at the engine. By the time it travels the ducts and gets to your crew heat system it has cooled to 200 degrees and is mixed with outside air.
Remember you car heater runs at approximately 200 degrees.
Regards,
Greg