If it is space heaters that you REALLY want, AND you do not mind maintaining / reducing your hash-rate, you could be better served by acquiring a set of S1's, underclock & undervolt them (to output ~125 GH/s @ - and don't ask me for a link, search the forum!) and replace the fan with a couple of quieter ones in a push pull layout at full pelt, aka blue wire hack; For a tad less power for both compared to your bitfury rig, you'd be laughing!