My fish room is in the basement currently, although it is not finished, the area is definitely enclosed enough that I would think it would affect my tanks. I have not noticed an real drop in PH in my tanks. Of course there has been some, but I would most likely attribute that to the lack of buffering in my tanks. (Pool filter sand, & rock) There's really nothing to buffer the water. As the other params drop, so does the PH. It will be interesting to see what my PH does once it is enclosed in a smaller area with the furnace and W/H.