You should know more than a mere ballpark figure.
The costs for installation will vary from region to region, but a good ballpark figure would be between $1000 to $2000 for the extra material and labor for the averaged sized new house.
In any other situation, where the exact value might not be as important, you can usually do the research yourself and come up with a ballpark figure.
While most receptionists are hesitant to confirm pricing without an individual consultation, you can get a ballpark figure of cost by being straightforward about your plans and expectations.
Remember that these may not be completely accurate, but can be considered more of a ballpark figure of the costs you will encounter.