Recommendations for a "summer" amp?

Living in a hot southern climate I'm considering acquiring a 2nd amplifier for summertime use as a backup to my Pass Labs amp which runs quite warm. Solid state, cool-running, fairly recent vintage (don't want to invest in service) with a used price somewhere below $800. I had a good candidate in storage but I gave it to my brother so I need some recommendations. My system is comprised of an ARC tube pre and B&W Matrix 800 series speakers.
Odyssey Kartago
Dig for Sunfire 2ch load invariant amps(SRA, 300 or 600). They run very cool(class T) and great musical performance.
Naim 5i-2 integrated
Rogue Audio Sphnix
I like the W4S ST500 on my N802's. You can absolutely hammer out the tunes and barely feel any heat from the amp. It is small and light, so easy to store when not in use. You should be able to find one close to your price range.
2nd the Odyssey amp...........
I 3rd the Odyssey amp.
I twelfth the Rogue Sphinx.
I'll second (or is it third?) the W4S. Cool, great sound, right price.
The 2500, new for under $600:
'Belles 150' with ARC pre probably would be great. Listen first.
There is a new invention called "Air Conditioning".
I used to have a high current amp in a sort of closet shelf space and I wired in a small fan to power up with the amp...problem solved.
Ron, we have a/c in hot climates and don't like adding extra heat to a room for the a/c unit to combat. It's 106 today and my house is set for 79 when I get home. I'm toughing it out so far this year with the tube amp.

The plasma tv is really noticeable in the summer as well. In the winter, I can run the tv through the tube amp all day long and don't even notice. Summer time, I am well aware of the heat pouring forth.
Hey Rrog, that new invention makes a fair amount of background noise, particularly when running a hot amp and television in a closed room, which is why it's best to keep the heat down.

Try it some time - you'll see.
No one should apologize for not wanting to run an AC unit just to listen to some music comfortably.
Class D
Snofun3, You need to upgrade your AC.
Abrew, if you are a real Audiophile, you should instead be considering a summer home up north for your amp.
I'm not real phile, but I really think of summer home up north for myself.
PSE Studio IV runs cool, sounds good! Perfect summer amp.
06-24-13: Theduke
"PSE Studio IV runs cool, sounds good! Perfect summer amp."

Yes, but where do you find one?
Thanks for the recommendations.

My listening room is on the west side which catches the worst summer sun and the hot amps just make the AC's job that much more difficult.
I think a quiet room fan obviates any tube amp issues from the heat sensitive among us, and a quiet fan won't disturb the experience any more than hearing Uncle Clem outside with your cousin Betsy screaming from the moonshine still behind the pigs. Merely moving the air around can really mess with the BTUs...swine British!
I live in Antarctica.

My favorite Summer amp is the Krell KSA-250.

Even with all the windows open it keeps my living room a very comfortable 68.4 °F.

On a slightly more serious note: If you have budget, the Odyssey Stratos have about 30% more juice than the Kartagos, which your Matrix 800s will gleefully put to good use.
QUAD 606
The Luminance Audio KST-150. It is a high speed, high bandwidth mosfet amp. It runs very efficient like a digital amp and is cool to the touch, but its sound will blow any digital amp out of the water.

In fact you will probably not want to put your Pass amp back in once hearing it, a true giant killer. It needs a week of break-in, more so than the typical new amp.
My "summer amp" is the Marantz AVR in my HT system. The sound quality is good enough considering that the noisy AC unit is running full blast anyway, which trumps serious listening.
You guys need your AC units checked. Mine is whisper quiet.
I would suggest any of the upper-tier Parasound amps from the 2-channel HCA series: HCA-3500, HCA-2200II, HCA-1500 (in descending order of wattage/power). Between 10 and 15 years old; should range in price, used, from ~$800 (HCA-3500) to ~$350 (HCA-1500). They're all rated for 4 ohms; the 2200II is rated down to 2 ohms. The 3500 and 2200II are probably the ones you want for those speakers.

I totally share your need. Have a pair of XA160.5's. Prior to acquiring these 131lb. marvels, I modified the %$^# out of a Hafler 500. I don't mind and will share info on the many multiple mods if requested, but the short of it is the 500 is a pretty cool amp - literally and figuratively. If one can be found that's been modified by John Hillig @ Musical Concepts, it'll provide the needed dividends. Parallel to my Pass, its soundstage is as wide and deep. One thing that continues to be so engaging is the height of soundstage with the 500. This is one attribute not shared with the XA 160.5 - which is not to say I am anywhere dissatisfied with it. Jus' sayin....