Those magical days when the HVAC is off

@ostemo8- your original post and the comments it has generated have raised a number of different issues relating to different kinds of "noise." When I was doing the whole house generator, I was looking at the current draw of air conditioners- some of the older type units pulled a huge amount of current on start-up- in the neighborhood of 100 amps! Newer units are not only far more efficient but depending on the type of compressor for the air con, can vary significantly in start up power and running power draw.

You have gotten some good input on noise reduction within the listening room relating to HVAC and overall noise reduction in the listening room. You may not have the luxury of starting from scratch in terms of construction--my room was done within an existing 1880s house that had been completely restored to high preservation standards circa 2004. Some of the things--insulation for example- were done by the previous owner, but the air conditioning units (and furnaces, along with electrical work) were all done by us after we purchased the home in 2017.

One thing I suggest before people get spendy on power accessories for hi-fi is to have an electrical system "audit" done, preferably by a commercial level electrician. I have had the meter pulled by the utility to check the meter block (corrosion can be an issue), and to go over the main service panel, both for integrity and wiring. When I did the electrical "subsystem" for the hi-fi, I specified a sub panel with copper buss bars. That is what feeds the big iso transformer, via 4 gauge wire, which can help with some electrical "noise."  This additional service is then fed from the output of the iso transformer to the listening room in 4 gauge to another service panel adjacent to the listening room, where the dedicated lines (10 gauge) are fed.

It is certainly possible that the HVAC system is contributing to electrical "noise" on your hi-fi but it probably depends on the particulars of the HVAC units, their age and how they are wired, all in relation to how the hi-fi electrical is wired. Most modern houses are 200 amp service, but the reason I like an "audit" is that a lot of problems start with corrosion, bad wiring, deteriorating service panels (in Texas, it is not uncommon for the service equipment to be outside, not in a basement), placing further demands on your electrical system given the elements.

When I had the back up generator installed, I also consulted Rex, one of the guys who helped Fremer sort out the electrical system nasties in his system. Rex can do this remotely, for a modest fee, using photos, drawings and phone calls.

Otherwise, I think you’ve gotten some good input here, including from the contractor @rock-on for all the different factors that go into new construction.

I’m no guru, I’ve done a number of dedicated rooms over the years and learned from each experience. A lot of this is know how, rather than just buying a black box. Because my house is old, and the floors are all longleaf pine (stuff that is now quite costly to find and replace), I also stiffened joists and added a subfloor where my turntable and front end is located. I still needed better isolation for a very high mass turntable (245 lbs), so had to resort to a big Minus K isolation system, which sits under an HRS platform. That does not seem to be an issue for you, so it is irrelevant but it does show the lengths to which you might need to go in some existing situations where you don’t have the luxury of starting from scratch.

Bill Hart

It is listening bliss when it’s chilly enough to have the windows closed, but not cold enough to need to have the furnace running.

Some great ideas given! 

I had planned to wrap my upstairs air handler in soundproofing blankets and I bought Dynamat to line the inside of my air handler access wood door. But at the lower air grille intake/electrostatic 23.5"x23.5" air filter is where the majority of the noise is generated. I turned down my handler's pull power but still. About 30db. I don't know how to mitigate that.

I like the simple idea of pre-chilling the house before any serious music playing. My house is concrete bricks so the helps with temperature regulation. 

This is an interesting thread.  We also are enjoying cooler weather in Chicago and yes it does sound like my system has kicked it up a notch.  My house is is 110 years old and my listening room is in the upstairs which is routinely 10 degrees warmer than the lower levels.   The tubed equipment in the listening room also pumps out heat which makes me further crank the ceiling fanI tend to listen to my HT system in the basement in July and August for that reason but it’s great to be fully enjoying the main system with the window open!

In my house of stereo, I use a whisper quiet in wall AC/heat unit. Since the construction is ultra insulated, all I usually ever use it is on the dry setting. I can't hear it even with music off. Meaning I enjoy comfort and ultimate sound no matter what the outside temp is. And I'm around Austin, Texas, no relief from heat yet, 103. It did cost a lot to build the house of stereo though. Like the saying goes, you get what you pay for.