Very helpful! One of the pipes is hot water to a sink and the other two are cold water and wastewater. In that case I think I’ll do some mdf / scrap wood then fill remaining hole with steel wool I have in hand. I’m guessing the hot water pipe wouldn’t be enough to pose a fire risk with the steel wool / mdf?
Don’t dual hose portable AC units follow the same principle of venting the waste heat outside? As I understand it, the window AC units are still much more efficient at this as they don’t have a hose to push/pull it through.
