recommendations for amplifiers that don't emit tons of heat

I had a similar dilemma a year or so ago.  I have a Pass Aleph 4 (100W/channel) that sounds great but is also a great space heater. Was looking for a suitable "summer" amp that didn't compromise on sound.  I auditioned quite a number of Class D and Class A/B amps and others, including many, if not most, of those mentioned above.  Ended up stumbling upon a used Linn Akurate 4200 at a good price, 4 channels w/200W each into 4 ohms.  Though I wasn't looking to bi-amp my speakers, that's what I ended up doing.  Sounds much better than all the alternatives I heard by some margin.  Runs cool, doesn't idle at 500W, and takes up little space.  My electric and air-conditioning bills dropped substantially, and the air-conditioner can now keep up when I listen to music even on the hottest days. Something about the pitch and tunefulness that just sounds right. Violins and sopranos don't have that edge that I hear so often even on many very high priced tube and solid state amps.  Linn doesn't seem to have much of a presence here in the U.S. where size, power specs, and "slam" matters so much and seems to impress many listeners.  Linn's focus seems concentrated on Europe where listening spaces seem to be smaller and more intimate.  I listen to quite a wide variety of music including a lot of classical music. I don't think Linn gets its due.