527. Why You Shouldn't Use Air Deflectors
28 Jan 2026 · 6 min
Derek Cole explains why HVAC vent deflectors backfire. Your system is designed to condition exterior walls and windows, and deflectors disrupt that airflow, creating comfort problems instead of solving them. He shares how fixing a customer's ductwork revealed the real issue.
Chapters
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 deflectors for your HVC system. Now, air vent deflators, you've probably seen those plastic things that go over your, your grills at home where, you know, you might have some curtains or something blowing. 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 middle, but the older home will have inside, in, inside the home, inside the wall. I mean like blowing at the wall and not attacking the outdoor, the outdoor wall and the newer homes, newer is in, you know, probably, you know, 60s or 70s on where air condition was designed to be in that space. You have seen them designed to attack the, 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, 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 fitting it, you're going to run into some comfort issues. That's where you have 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 we actually redid their duct system. There have 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. 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 going 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 compromised, you're going to have challenges. Because H3C 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 deflectors 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. 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, you know, obviously I understand people, you know, still have them, 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, 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. But, but now you know.
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