Wood stockade fence will definitely help. You should plant evergreen shrubs on either side of that fence as well. They are good at absorbing sound because they have thick low branches. Consider planting a tall type in the back, closest to the fence, then a medium height of different color and leaf typ, and finish it off with low shrubs to block noise from underneath the fence. You can also attach sound absorption sheets to the highway side of your fence. Make sure these go all the way to the ground, if you can see what Is making the noise through any spaces, you will be able to hear it. Check out these articles: Trees: https://www.gardeningknowhow.com/special/spaces/noise-reduction-plants.htm Construction and material Overview: https://www.thisoldhouse.com/ideas/yard-noise-reduction Sound absorbing materials: https://acousticalsolutions.com/reduce-unwanted-outdoor-noise-sound-blocking-fence/

The reason I know what I know about this topic is that I had to do a giant "science project" learning exercise back in 2007 before I could order anything for my kitchen reno. You have an aperture that is not larger than 3 ft by 1.75 ft or about 5 square feet (roughly). In my view, the actual flow rate on maximum should be around 90 cfm per square foot, which gets us to around 450 cfm actual flow rate. A VaH (at best) meets its claimed flow rate when the hood is hanging in the air, and there is no other restriction (pressure loss). However, in real life, the hood has exit ducting, a roof cap, and the make-up air has some restriction. (Even an open window with a screen can have an effect.) For baffled hoods, I use a factor of 1.5 for zero static pressure loss flow rate to achieve the desired flow rate with restriction. (This assumes a reasonable hood cap or roof mounted blower housing.) While the VaH doesn't have baffles, the data that appeared here a few months ago indicated that their flow reduction with pressure loss was greater than typical Broan blowers that I have data for, so I think I'd stick with the 1.5 factor. The product of 1.5 and 450 is 675 cfm, so I think 600 is a reasonable design point for you. What you may find running only 300 cfm is that you can cook smelly things on simmer or reheat precooked sausages at a low power level and capture and contain adequately. Higher temperature cooking associated with griddle use, searing, or wokking will produce faster rising effluents that may not be well captured and contained. Note: I use 10-inch duct with a 1500 cfm roof blower probably pulling an actual 900 cfm. Your 7-inch duct has only half of the sectional area, but only needs to move about half the actual flow. There will be somewhat more duct friction per sectional area with the 7-inch duct, but I would agree with VaH that the roof cap needs to be suitable for the flow rate. 600 cfm hoods with a minimum of a 7-inch duct recommendation likely can do so by using a blower that has a more vertical fan curve between the zero static pressure (rated) flow rate and the flow rate they are expected to actually operate at. Custom kitchens seen in magazines often have no ventilation at all. After all, they only need to look nice. Food is catered, or else the staff cook in a more industrial kitchen off limits to guests. :) kas

Check above the rooms (under the roof) for dead animals in the attic. Squirrels and mice are common invaders. If you have a chimney on an outside end-wall of the house and the chimney goes though the peak of the roof, that may be an entry point. Builders may frame the house and roof before the chimney is built (full brick chimney). After the chimney is built, there may be a gap where the eave box meets the chimney and the top side is bridged by roofing shingles, but underneath, the eave box does not meet the chimney. This is were squirrels entered my house. They got inside the eave box, moved down to the soffet (where the rain gutters are) and now had a lateral run the length of the house. They could enter the attic anywhere they pleased.

Your experience may be correct and it woud be hard for me to disagree without knowing the exact details of what you did. If you were to compare STC or OITC ratings of manufacture of the same window , one with dissimilar glass glass package in dual pane and one with triple pane. You would see virtuallly know difference in the numbers. In most cases with a window manufacturer that produces windows for sound control you would find no triple panes offfered. The science says otherwise But if what you do works , it works. I have triple paned unitsbin my house and I know when a car drives by when I’m awake at about 200 ‘.