What is the sound level of Your Listening Room?

I am curious about what the sound level is at your listening position with your system turned off. I have checked mine and during the day it is about 43 dB and at 1:00 a.m. it can be as low as 28. I can improve the daytime level to 35 dB by turning off the refrigerators and air conditioner. What have you done to improve the sound level of your room?

I am considering adding a listening room to the back of my garage (wife is on board because she needs more storage space) and if you have made improvements that have reduced your ambient noise, please share them.