You don't need that until the very end. They should be modeling many houses first, and they can get that by having employees measure their own house. They should also know something about the edge cases and have a lot of very unrealistic houses modeled.

Then they should have a lab with real furniture and movable walls so they can do controlled real world tests. Once the above tests are done you add confidence with random real world tests.

The types of problems seen here are things that your lab tests should fail and keep you out of real world tests. Particularly when the test subjects don't have some sort of test agreement