Since no fan isn't an option, I can tell you that my large inverters have large fans that are temperature controlled and variable speed. Most of the times the fans are not on or on so low that you can't hear them. Being larger means that when the fans do ramp up, they are not running at the RPMs that the fans in the smaller inverters do. My Powerbright cw150's fan sounds like it is trying to get a 777 off the ground just running the TV/Satellite.
BTW
If you can get past the PSW buzz wording, the Tripp-lite 1250fc is a wonderful inverter. It is MSW but my chargers and satellite box ran cool on it instead of hot like the little MSW unit. It is also much more robust than the Powerjack 3000w PSW inverter we used last year. That unit started the air conditioner ONCE and died. The Tripp-lite runs it all day and I'll be adding a residential fridge for longer trips.