This is more a quick rundown of my flowhood that I made almost two years ago. Very Basic and efficient design. Minimal and cheap produces. well, everything but the True 99.8 Hepa filter. that was around $225 with shipping. I could be wrong. I got my filter before I built in and that took many months Front View(Above) Side View (below) The Box is made out of 1/2 Plywood. white with latex paint. Put cheap handle I had to move it around. I chalked every seem on inside and around where fan hole cut out it. Put that cheap leftover filter thing I found to help inlet air one side of the fan. A light that I had hanging around. Low budget for sure. I got theUsed Furnace Fan for $30 off CL. I did need to get a capacitor for the fan. that cost like 10-15 bucks if I remember. plus I add the fan light switch to adjust fan speed when in use. I had to be around 60 buck total to get the fan part up and running how i wanted it to. here pics of those add ons. Here is the motor spec if any questions on that I have it wired as constant High but with the adjustable fan switch, I can change the speed quick and easy. Yes, it does have a per filter! before I forget to really explain the little bungee cords are there to hold the Hepa filter on the prefilter tight. i have a sill about 1/2" inside that has weatherstripping. then I placed a prefilter then the HEPA is against that and the bungee cords hold everything tight. I have little screws on the back of the box that other bungee hooks to. here is a pic that shows it best I could without totally taking things apart. Hope this helps someone, thinking of how they can make there own flowhood. if you are kinda handy.