Your house isn't worth what a someone on a website, that has never been in your house, tells you it is worth, it's worth what a professional in the business, after evaluating other homes that she knows, tells you what she THINKS it's worth. It's actual market value is determined by what someone is willing to pay for it. Website estimates are nonsense!! The online estimates are so far off, as much as 40 percent off! Don't even THINK about relying on an online estimate for the value of your most valuable asset. And as far as values of Antique homes in particular? only an expert in antique homes, who knows antiques, can give you a good value estimate on your historic house.