As an example of how the new box type infared heaters with a fan work, from Heaterlab.com.I own a SunHeat and it does a much better job of heating either my travel trailer or motorhome than any standard portable electric I have ever owned..I use mine in the house also.
One more great infrared heater by the LifeSmart brand. LifeSmart Power Plus is designed for heating rooms with up to 1500 square footage. This unit equips 6 quartz infrared elements. Each one is wrapped in a metal coil that acts as a heat exchanger. Having 6 elements it produces more heat.