MVHR cooker hood idea

[Adsibob]

We’ve decided to cut a gaping 6” hole in a wall to vent out our cooker hood. I will post a video when I next cook steak, but basically the way we designed our recirculating was a f&@king disaster which anyone with any basic physics knowledge would have known wasn’t going to work. 
so that we don’t completely ruin our very effective airtightness, can anybody recommend an external vent to cover the hole which pretty much self seals when not in use? It didn’t doesn’t have to fully seal, but something that prevents a noticeable draught would be good.

[dpmiller]

If the duct runs vertical for a bit, there are good sealed gravity flaps available. That's the route I took. Motorised damper is another possibility.

[Adsibob]

13 hours ago, dpmiller said:

If the duct runs vertical for a bit, there are good sealed gravity flaps available. That's the route I took. Motorised damper is another possibility.

Thanks @dpmiller, don’t suppose you could post a link to such products?

[dpmiller]

something like this

https://www.ebay.co.uk/itm/255271428161

as the rubber seal works commendably well. I did however glue a washer onto each flap, to weight it a bit more and ensure it *only* opened with the strong flow from the hood.

 

For motorised, you're probably looking for a spring-return fire damper unit, as the cheap chinese motorised units require an odd switching logic that would be difficult to integrate with our way of wiring things, IMO.