Need A 10-30 watt Tube Power Amp, Lower Heat Output, Which Sounds Great, Under $1500 Used

I am in need of a mid-spring to mid-autumn power amp. This is for my office system that gets a LOT of use and is therefore very important, in terms of sound quality. I have been using a great SET amp, but the 845's it's based around simply heat up the smaller room space too much during warmer weather, even when running central air. I've been in the tube audio game a long time, though, and know there are amps with designs and tubes that run far cooler and wouldn't present the room heating issues. 

I pondered something solid state, but there simply isn't much in the power range, which is also within my price range. Also, I would want an amp with at least some tube-like sound qualities, which makes it even more difficult. In a perfect world, something like a First Watt F7 would be ideal, but its twice my budget, used. 

10 watts would do it, but anything up to 50, or so would be fine, of course. It will be powering Omega, single driver speakers of 94.5 sensitivity and be paired with a Zesto Leto preamp. 

Any suggestions would be greatly appreciated. Thanks!