In this video Derek Cole presents a controversial but technically grounded opinion that air vent deflectors should not be used with residential HVAC systems. He explains that modern HVAC designs are engineered to condition the exterior walls, windows, and other exposed surfaces of a home, delivering air directly to those zones so that heat gain or loss is countered at its source. Deflectors, which are plastic covers placed over supply registers to redirect airflow toward the interior of a room, disrupt this intended airflow pattern. The result is uneven heating and cooling, hot or cold spots, and reduced comfort because the conditioned air is no longer attacking the exposed wall where it is most needed. Cole illustrates the point with a customer case study: after redesigning the ductwork and removing a deflector, the homeowner experienced balanced airflow throughout the house, eliminating a previously uncomfortable breakfast nook and eliminating curtain‑blowing drafts. He emphasizes that HVAC systems are not plug‑and‑play devices; they must be properly sized and designed for each home. While he acknowledges that some people still choose to use deflectors, he argues that an educated homeowner should understand why they are unnecessary and potentially harmful.
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So I know from the beginning this is going to be a very controversial opinion, but I'm going to explain why you shouldn't use air vent deflators for your HVAC system. Now, air vent deflators, you've probably seen those plastic things that go over your your grills at home, uh, where, you know, you might have some curtains or something blowing and you want to, you know, put that plastic thing over so air shoots to the middle of the house. Well, air vent deflectors should not be used, and I'll tell you why. It is made— your home is made, your system is designed and made to condition the outside walls, windows, exposures of your home. It's, it's made to attack the outside wall. So if you have your house, all these outside walls have vents on them, and you'll see this everywhere except for an older home or even a mobile home. They'll have them towards the middle, but the older home will have inside inside the home, inside the wall. I mean, like blowing at the wall and not attacking the outdoor, uh, the outdoor wall. And the newer homes— newer as in, you know, uh, probably, you know, '60s or '70s on— where air conditioning was designed to be in that space, uh, you have seen them designed to attack the outside walls. That is where your hot or cold exposure is coming from. It's coming from the outside wall, the window, the door, uh, whatever is there is attacking that space so the inside of your home can be comfortable. So what you're doing with the air deflector is actually taking that air that's designed to condition the outside wall, and it's designed to shoot up. It's almost like a mushroom shoot up, hit the top of the wall, condition that space, and then kind of like a curtain go down and condition that wall. So once you start changing that or affecting it, you're going to run into some comfort issues. That's where you have, uh, cooling or heating, kind of uneven hot and cold spots. You're taking that air that's designed to be on my wall and you're pushing it inside the room where then it's trying to get back out to the outside. So you don't want your curtains to blow or something like that is it's a very minor inconvenience because it's designed to be on that outside wall. I was at a customer's house one time and, uh, we actually redid their duct system. Um, they were having some challenges, so we, we did it. And the husband said, you know, before we get finished, I want you to walk through with me. I was like, no problem. Uh, so get to the home, is like right there at the unit on that wall, my curtains used to blow up and now it's not happening. I said, well, you're still comfortable in the house, right? He said, yeah. I said, because it's designed properly, it's not going to blow everywhere, and then you have your curtain to go up and down. And he also had like a breakfast nook, that never got comfortable. I said— we walked over there. I said, see, now you're getting equal amounts of airflow here as you are there because your system is designed properly to have that airflow. When it's just put in and not comfort-sized, you're going to have challenges because HVAC isn't something you pick up at the big box store, plug it in, and you're good to go. No, it has to be designed, comfort-sized for your home. Air deflators should not be used. If it's done— if everything is done properly, it shouldn't be an issue. When you run into an issue where you're using air deflators it becomes a problem because you're not attacking that exposed wall or exposed window with the air deflector. So it's a good reason not to use them. Uh, I've been into homes where they've been in there before. Once you, you know, once you educate on what's going on and, and why you shouldn't need those, um, You know, obviously I understand people, you know, still have them, uh, still want them, still need them, and that's fine. But when you're educated as to why it shouldn't be good and why you shouldn't need it, um, you should be good to go. But it's like anything, make it— make a choice. And if you want to use it, you want to use it, uh, but, but now you know.
