I have no clue what they are talking about.
As I mention earlier, the only thing I can think of that makes any sense is that they are using highly concentrated hydrogen peroxide as a source, when it decomposes water and heat and oxygen are the by products (2 H2O2 -> 2 H2O + O2 ). But I cannot see this stuff in a household installation, its highly unstable and very dangerous to handle and store. Plus, as I mentioned, it takes a great deal of energy to make the stuff.
Not familiar with the SF tale.