[Greenbuilding] small direct vent gas wall heaters

[Reuben Deumling]

I've come across a small (~6,000BTU/hr) vented gas wall heater:
http://www.ventedcatheater.com
This company used to make a 120V version, but the power consumption for the
fan is higher than I wanted:
720 mA   86.4 Watts Start
340 mA   40.8 Watts Run
120 mA   14.4 Watts Standby

The manufacturer suggested I look into 'some kind of gravity vent gas heater
that is manually operated with millivolt controls.'

Do such heaters exist? Are there other ways to thriftily heat an 80 sq ft
basement room with well-insulated walls and a not so well insulated floor?

Reuben Deumling