Being based in Sydney, I do all my processing at 24ºC. The water from the tap is as near as damn it to 24º in summer where I live and that means I only have to fart about during winter. It is much easier to warm the solutions than to cool them.
In winter, my containers of chemistry stand on top of brewer's mats and if I switch them on in the morning they'll be up to temp in the afternoon.
I am currently using a Jobo ATL 1500 for 4x5 and it is automated to run at 24º for B&W.
Of course you could always buy a tempering unit and plumb it into your darkroom. But it is costly to buy and costly to install.
"Photography was not a bastard left by science on the doorstep of art, but a legitimate child of the Western pictorial tradition." —Robert Galassi