Basically what is involved is the appraiser evaluates the inside and outside of your property. Generally they take photos and measurements as well. Most often it is pretty quick and easy.
The refinance appraisals we've gotten where I am employed have been much lower than expected. A home that appraised for $159,000 three years ago, now appraises for $130,000. I would suggest getting two appraisals because they can be very different.
A qualified appraiser will come to your home and look everywhere, including the outside. He may take measurements and will write down all of the extras your house may have.
An appraisal for a refinance is usually just like an appraisal for purchasing a house. The appraiser will make an appointment to look at your home and record its features. The appraiser will then compare your home to similar homes that have sold recently to estimate your home's value.
An appraisal for refiancing in the current market, unfortunately will probably yield the following. A bill for between $300 and $500, a sick feeling when you are told how much your home has depreciated and a rejection for the refinace. In better economic times the results were much more positive!