The FZ120 Zen does what I believe ZEROtherm wanted it to do, and it does a great job. It has performance very close to that of the Nirvana, is quieter than the Nirvana, and is cheaper than the Nirvana. The Zen can be found for $39 + shipping, and that’s a steal. With a price like that the Zen is an inexpensive upgrade for anyone, and is almost (depending where you shop) $15-20 cheaper than its bigger brother, the Nirvana...