I am currently doing a 420sqft extension on the back of my house that includes a bathroom. All of the outside walls have been sealed on the inside with spray foamed at all of the seams, and the outside has been wrapped in Tyvek and 1/2 foam before vinyl siding. All of the drywall in the extension will be sealed with gaskets per ADA. The whole house including the extension is insulated with Roxul mineral wool. The original part of the house is not sealed per ADA, but is wrapped in Tyvek paper and .5 foam – I believe the seams are untaped. The house is heated and cooled with mini splits. I was unsure if this type of construction would require an ERV, or if it is leaky enough that it wouldn’t be necessary and maybe I’d be better off running my bathroom fans more frequently. Are there any ERVs that can function as a bathroom fan? Also, are there any ERVs that anyone knows of that includes a light. I was reading a little about the Panasonice Whispercomfort, but I have heard mixed things about whether or not it can be used in a bathroom. Also, it looks like it doesn’t come with a light, which is a feature that I would prefer. Thanks for any input.