No one can accurately say whether one property is worth more than the other without actually viewing the homes. There may be other factors that may effect value that you are not aware of. Truth is market value is finally determined by what a ready willing buyer is willing to pay for a given property and what a seller is willing to sell for. Here's a question for you. Do both homes share the same owner? Is this new construction. Is the bigger lot actually useable with trees etc. cleared? Is this new construction?