My wife and I are considering purchasing an existing home which is too big for our family. Other features of the house come close to outweighing the fact that it is over-sized. The main problem is that the house was built with a finished attic, which adds about 500 sqft to the size of the house. We don't want to heat/cool/clean this space.

Would it be possible to "mothball" this finished attic? What I'm thinking we could do:

- install a wall with a door at the top of the attic stairs
- close off HVAC air outlets and return (combined forced hot air heat and central air)
- locate supply pipes to attic bathroom sink, shower & toilet and install shutoff valves and drains to prevent water from freezing & cracking pipes while the space is not heated.
- temporarily seal shower, sink, and toilet to prevent sewer gas from entering the house when the water fully evaporates. Is this possible to do without removing them? Like by coating some baseballs with plumber's putty, and putting them in the bottom of the sink/toilet bowl/shower..?

We live near Richmond (so lows in the teens in the winters, highs near 100 in the summer, with humidity, likely much hotter in the attic). Do I need to worry about the drywall, paint, or carpet deteriorating rapidly with temperature extremes?

The idea would be to able to quickly revert the space to "finished" status in case we wanted to sell the house, or really even if out of town guests were coming to stay for an extended period.