Those magical days when the HVAC is off

@ostemo8 I didn't mean to hijack thread from your electrical concerns to the noise issue, AC quality is an important issue, its just that its common to see threads attendant to electrical noise on AC grid and or home AC, I see very few threads on the environmental noise issue. Outside of the audio equipment itself, AC quality, listening room treatment and noise pollution (both home and external generated) are equally important for maximizing system potential.

The most irritating thing about ambient noise levels is often one has very limited control over it. Rock-on has great ideas for minimizing it, but many of us don't have option to implement all of those ideas. You can turn off your HVAC at certain times, but other times you just have to put up with it, the issue is once you've experienced those magical listening sessions when ambient noise levels were at their lowest, subsequent listening sessions with higher ambient noise levels may impact your enjoyment.

Doesn't bother me at all.  Equipment is manufactured to be so silent that the sound quality is not compromised.

Happy Listening.

My system is on all day for my wife's background music. The HVAC runs around the clock in summer (southern Nevada). One benefit of class D that people overlook is the much lower amp draw. I had an electrician look over my 500 watt class D system and he said it was nowhere near unsafe or needing any special wiring. We're on a solar net metering plan trying to go net zero. 

We demand space, price, and energy efficiency from all our residential systems including audio. It is producer degree of difficulty, technology, simplicity. Our Yamaha NS-5000's are an example: 3.5 pound woofer coils with proprietary carbon fiber in all three drivers in a 600 watt studio monitor built and painted in a piano shop.

@bigkidz +1

On another site a member was chest puffing about all the money he spent on his dedicated listen room, dedicated lines, and equipment, but then stated that he needs to disconnect his refrigerator to maximize his listening experience. Obsession for some

As a lighthearted note regarding home music rooms and protecting against external noise, even the best plans go awry. I had carefully reviewed the blueprints being used by the prime and subcontractor team. Since the architectural design, construction, and amenities were largely inflexible and I was unable to be on site, I was compelled to restrict my personal inspection to designated phases. The bottom line is that the construction manager took it upon himself to change location of attic and wall access points, air ducts, and electrical power outlets. He also decided it would be easier to locate the bi-level HVAC unit adjacent to the only long wall and place the air compressor right under the listening room window. He also informed me that the parent construction company did not authorize glue and screw for upstairs composite flooring and only used nail guns. And by the way, the high grade padding and bur-bur carpeting was no longer available, since negotiations with their supplier had broken down. [NOTE: The cautionary statement: "We reserve the right to change specifications and construction materials... " is there for a reason.]

So my wife and I moved into our new "dream" home in Summerville, SC. Shortly thereafter, I noticed a high level of humidity and musty odor in the upstairs music and collectibles room. "Whoops!" The window and room vent exhaust contractors forgot to seal the units and the incessant rain and humidity quickly saturated the wall and ceiling board. And the upstairs floor creaked and squeaked with every step, which the contractor remedied by pulling up the cheap pad and carpeting and yanking out the nails with a crowbar.

However, there is good news. When the house was hit by lightning, the strike was largely diffused by running to ground. Unfortunately, I had failed to unplug my audio equipment from the wall and the amps went into protective mode. But that's another story.