So -- your neighbor's 2400 SF, circa 2000, 4 BR, 2 BA home just sold for $300K.  It's probably reasonable to think that your 2400 SF, circa 2000, 4 BR, 2 BA home will also sell for $300K, right?  After all, you have made the same updates (systems and cosmetic) over time -- and you're on the same street!

Well, maybe -- but maybe not!

Consider the possibility that....

• Your neighbor's home is a Colonial with 2400 SF split between the first floor (1200 SF) and the second floor (1200 SF) and is built on a crawlspace.
   
• Your home is a ranch style home with 1200 SF on the main level and 1200 SF finished in the basement.

These two homes will not be seen as having an equivalent value -- not by potential purchasers and not by an appraiser.

Above grade square footage has a higher value attached to it -- both specifically by appraisers, and generally by purchasers.  Even if all of the other factors (condition, age, location, bedrooms, bathrooms) are the same between two houses, if one has a significant portion of the square footage in the basement then it will be seen as less valuable than the home that has all of its square footage above grade.