Heat

Motron looks like AC Infinity with less features for more money.

I use two computer fans underneath 845 SET amp, tremendous current and heat from these transmitter tubes. Don't bother with my other tube amps and pre.

Then if the room is cooler, the heat s being drawn through the heat sinks with greater efficiency?

Then if the room is cooler, the heat s being drawn through the heat sinks with greater efficiency?

Yes. Cold air consumes more energy (heat) from the cooling than warmer air can. 

Two factors come into play. 1.) The colder the air, the more heat it can absorb before it reaches a temperature where it will no longer absorb heat from the sinks. 2.)The faster the rate you can replace the air that has already absorbed heat from the sinks with cold (room temperature) air, the faster the rate that heat can be transferred away from your amp.

Theoretical, or actual amp in an attic? Summer attic temperatures are like this

https://www.youtube.com/watch?v=EhZba-P7R18

Pushing hot air at a hot thing ain’t gonna do much. Attic exhaust fans can avoid extreme temperatures, but not enough IMO.

A box with small personal ac unit can work, however, power on/off, settings, and importantly condensation needs to be dealt with.

Some floor standing room units have ducts to vents like a clothes dryer, that would work if that could be worked, again, an enclosure to retain the cooler/block the hotter air would be wise. I used one of them to cool the V Berth in a boat in Florida I inherited (thankfully sold) found one with self evaporation, pvc pipe for heat exhaust.