Hi All,

I have a natatorium with a tall ceiling (19′) and an exterior exhaust in it. It’s an insulated chimney that runs through the house attic and exhausts pool room air to atmosphere using a whole home exhaust fan. 

I want to find the best R-value and air sealing horizontal gravity exhaust damper so I don’t loose a ton of heat but can still exhaust when needed. I’ve been in a very deep dive online and max R-value i can find is R6 (which isn’t bad considering what it does). I did find one product that guarantees zero air leak. I’m not certain if I want zero air leak or maximum insulation value. I would think both. Anyone have some product ideas? It’s only a 24″ opening. 

I am also going to look at replacing the whole home fan with something that includes a back draft damper. The fan was installed in 1995, I’m not sure it has any back draft component. 

Thanks!