From a loyal blog reader...
"I used your lovely search tool to look at all of the Belmont Estate listings. One thing that surprised me is the vast difference in the price per sq ft. Some were as low as $88 and others were as high as $139+. I'm curious to know why there's such a difference."An excellent question! Here's what she was noticing....

One reason for these differences is based on whether the homes have basements. You'll note (below) that the three homes without basements have a much higher price per square foot than all other homes in the neighborhood. What is really going on here is that when you start to add basement finished square footage into the "total livable square footage" (which is then used to calculate price per square foot) you are able to achieve a much lower price per square foot in a home with a basement. So....while the homes without basements seem to be really expensive on a price per square foot basis, it's really that the homes WITH basements are able to look less expensive using that metric.

Another item to notice is that the largest homes (on a total livable square foot basis) are able to achieve the lowest price per square foot (see below). Three of the largest homes in this group have the lowest price per square foot.

Given all of this, remember that it is best to compare relatively similar homes using the price per square foot metric. If some of the homes you are comparing have basements, and others do not, or if they are vastly different in total livable square feet, then you are likely to find significant a variation in the cost per square foot.