What power conditioner will help in my situation?

"I turn off the AC or heat, due to fan noise and circulating air, when I listen."

I guess many of us do. I do, but there is that other problem, "Is your refrigerator running?" which despite the old joke many of us do wish it would runaway considering the disturbing noise these modern refrigerators make. Smaller homes where listening spaces are in close proximity to kitchen is real concern, for unlike AC/heat shut off at thermostat, shutting off a refrigerator full of food invites real risks.

Aperez -

a dedicated line to your system would be the best option.

I had that same problem before I put in a dedicated line. The switch for the ceiling fan was one that allowed you to increase or decrease the fan speed. I changed the switch to a simple on/off switch and the hum disappeared.

Where is the hum coming from ? Amp ? Speakers ? Ceiling fan speed controls can create DC offset on the AC line, and cause some transformers to hum/buzz. This is not a problem a "line conditioner" will solve. A dedicated line also may not provide a cure either, since it will be in parallel with the offending circuit. You need a DC blocker. Emotiva makes one.

A very inexpensive alternative is the Machina Dynamica Flying Saucer (a catchy yet uninformative title for this wonderfully efficacious audio accessory) inserted into the unused AC socket right next to the socket into which you insert audio or video component power cord.
Check if an unused AC outlet is built right into the base of the fan itself.
Also, insert the same product into any other unused AC power outlets throughout the listening room with its one shared power line circuit.
One of my listening rooms also shares a line with fluorescent lights, household appliances, ceiling fan.