The weather has been pretty warm lately so we've been running our A/C. I noticed that it didn't seem like much air was coming out of the registers, so I checked to make sure the blades/louvers were fully open. When I pulled out the register there was a HUGE difference between having the register in (and completely open) and removed. There is easily 40% more airflow when the register is removed.

We have a few "scroll pattern" registers that are a bit better, but I haven't been able to find them locally anymore. All of the new ones seem to use this plastic louver behind the decorative plate that looks like it blocks 50% of the air even when fully open.

Are there high-flow registers available (4x10)?

  • Could you provide a photo of the plastic louver you're talking about? Or a link to a product online that includes such a photo? Jul 22, 2012 at 20:44
  • I can't find a photo of one, but you can (sort of) see the plastic at the bottom of this one: homedepot.com/h_d1/N-5yc1v/R-202074575/h_d2/… Instead of 2 or 3 metal blades that rotate to block the airflow it's basically a grid in plastic (each grid "line" is maybe 1/8") and you can slide a piece of plastic sideways to cover/open the squares that are made by the grid. Jul 22, 2012 at 20:51

2 Answers 2


It looks like you can buy damper boxes separately from grilles. An example is here. You could also get a grille and install it without a damper box if you have no need to damp airflow from that supply vent.

Alternatively, just cut the metal/plastic that's blocking supply off your existing register and call it a day.

  • Yeah, I think I'm just going to remove the plastic backing. Jul 26, 2012 at 0:15

There are various sellers of louvered and non-louvered floor vents. These can be pricey though.

Of course if you're going to be replacing the existing cover anyway, you may as well try the other poster's solution of just removing the plastic from the one you've already got.

You titled your question 'high flow'; the above I'd consider more 'normal flow'. For people looking for increased airflow from a vent, there are also powered vent fans available. These aren't decorative and are more expensive.

For a custom/fancy outlet cover with high flow via fan boosting, I don't know of any products on the market, but the fans are essentially like computer fans you can buy for $5-10 plus a power supply and an airflow sensor/switch. Could make a great DIY project.

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