House appraisal estimates are needed by buyers and sellers. Buyers need to get an estimate of the value of a home before making an offer and sellers need to get an appraisal of their home value before setting the price of their home.  

To get the most accurate value for for the property you intend to purchase, will need a Professional Home Appraiser.  The appraiser will go to the home, measure it, and take pictures. They will then compare the home with other comparable houses and give you a written report.  When buying a home you will most likely have to pay for this service before getting a loan.