hvac time laugh i suck at hvac.....

ok i've got the main trunks ran and split off to the room. i am using 4inch flex duct for the last 10ft or so of the return and supply runs feeding the room. voila.



i've read that to ensure the vent is dead silent there must be a box before the exhaust\supply point. apparently this creates a lower pressure zone and the air slows down enough to change any audible whistle or whatever in the vent opening. i'm not even sure 100cfm is enough of a breeze to cause an audible vent noise, but i'm airing on the side of caution. [surprise]

to purchase something ready made is not easy here on the island. a lot of blank stares today and 'go see this guy over in stratford' a whole other town.... once i did finally find someone who knew what i was after, the price was 160bucks for a sheet of rigid linocoustic. duct not included. sick

diy to the rescue. here is what i came up with for now. eventually i will have to track down something to put into the box if i need to deaden the vent a bit, but that can be done after from the vent opening. there are 2 of these made. one for each of the supply and return 5inch diffuser locations. they will mount in the stud space beside the door and just outside the screen wall at about 6 inches from ceiling to center or so. i am hoping this is enough for ventillation in the room. it is powered by a 160cfm hrv unit that will exchange the rest of the house too. inside the room i plan on having a 3 position switch to turn the system to on then to high if needed. i thought about the whole 12v trigger relay auto turn on and off thing. doable but dont feel like doing up a relay box etc. in my already cramped mech room.

does anyone know of a good product to place inside a vent to muffle sound from escaping\entering a space[question mark] i'm not sure i'll need it with the flex duct, but better find a solution for down the road....

in the unlikely event i need heat, a 1500w wall panel convector is going in on the rear wall. i will set it at 18c or so and it will likely never turn on. a\c is not doable. too expensive to install and run later. frown