An appraisal is a report completed by a designated licensed professional who values a home. These appraisals differ from realtors and mortgage brokers.
An appraisal is a home evaluation that is based on the homes in the area and what they sold for. The process is based on what they call a comparative process.
There are a few other processes like cost approach, direct comparison and comparative approach
The majority of mortgages that are on a conventional level need an appraisal, but with any mortgage insurance like CMHC/Genworth /Canada Guarantee the appraisal would not be necessary. There are exceptions to this is where the value of the home is too high and/or if the home is a private sale.
Appraisers usually charge the clients the fee if and when needed.