[E Rod]

I started by using my phone camera in the duct facing towards the ac unit. There you can see a bend . From there i used a measuring tape to see how far back or close to the bend I could install the extra vents as i wanted them close to unit as possible. I did the same for both ac units. I installed a total of 2 in the bedroom, 2 in the kitchen and 2 in the living room . I replaced all the vents from some I purchased on Amazon that are more open and adjustable. Second, on the return air grille, underneath the unit , I used the existing return air's to locate where to install the 3rd grille . i drilled a 1/8 to 3/16 hole underneath . Using a piece of tissue with the ac on , if tissue sticks to ceiling, that's the return side, if push away from hole, that's the supply . I then did the cutout for the 3rd return grille right underneath the ac unit. Now it has more air supplied to it and you can feel the difference. I now just use once ac and on extremely hot days, sometimes both but rarely do i used the 2nd ac as the two ac's utilize the same duct