With the UK a bit warm, not much of the Tribblix home lab is running right now.
The T4, at 400W, is out of the question. SPARC development tends to be a bit seasonal (they're great in winter). Even the Intel servers at 100W or 200W aren't going to be running. So just my desktop (where, actually, most of the power consumption is from the display rather than the box itself). Even there I just leave a build running and go sit somewhere cooler.