Like millions of other homeowners, I recently refinanced my home mortgage. The result is, I’m saving thousands of interest dollars. But the key to the successful refinancing was the appraisal.

Although the appraiser’s estimate is supposed to be based on objective facts—usually recent sales prices of comparable, nearby homes—in reality it is highly subjective, because the appraiser must apply the available factual information to the property in question. In housing tracts or subdivisions where the residences are very similar, such as a condominium building, it is possible to use computers to estimate market values. However, most homes are unique.

That’s when the appraiser’s experience, ability, training, attitude and competence become critical, as he or she adds or subtracts value for the home’s pros and cons. Appraisal is an art, not a science. The weakest link in the home mortgage process is the appraisal, an officer of one of the nation’s largest home loan lenders told me about a year ago.

- How home appraisals are made. The three primary residential appraisal methods are: sales prices of nearby, comparable homes; the residence’s replacement cost; and the rental income approach. But the first method is the one most often used for residences, and it’s also the best. Recent sales prices of nearby homes come closest to indicating what the subject residence is worth.

If the purpose of an appraisal is for a home-acquisition mortgage, the sales price is extremely important. Sometimes, the appraisal shows that the buyer offered too much. If the purchase offer contains a finance contingency clause (as it should), the buyer can then cancel the sale if the seller won’t reduce the price. However, when there is another appraisal purpose, such as for refinancing or property tax valuation, the appraisal becomes more difficult.

To save money, some lenders use unlicensed appraisers for lower-priced homes. While a state appraisal license is no guarantee of competence in any profession, it’s fortunate that most lenders now hire only licensed appraisers. The typical cost is $200 to $400 per home appraisal, whether or not the appraiser is licensed. Thanks to computers, many lenders now only use appraisers for drive by appraisals at a reduced price.

- How to get a fair appraisal. Most appraisers are competent and conscientious, but a few are not. Since the appraiser is considered to be working for the lender, not the borrower, borrowers need to know how to get a fair appraisal. Here are the steps to take:

1. Be sure the home looks its best. Cleaning, repairing and painting add market value to a home. The yard and interior should be in the best possible condition.

2. Accompany the appraiser; ask for a business card. When meeting the appraiser, you or your real estate agent should ask for his or her business card. Inquire if the appraiser is licensed. If not, your chances of a bad appraisal greatly increase.

3. Hand the appraiser a list of the home’s features. A few appraisers resent the homeowner or realty agent pointing out the home’s features, but most welcome the information. Unless the appraiser takes careful notes, he or she can easily forget value-adding extras after a day of inspecting several homes.

It won’t do any harm to state on your information sheet either the sales price or your opinion of the home’s market value. Experienced appraisers realize if their appraisal is much different, they’ll have an unhappy borrower.

4. Give the appraiser a list of recent nearby home sales prices. If you know of recent comparable home sales in your vicinity, give the appraiser a list of those sales prices. The best appraisers welcome such information, because their sources are often months behind. However, the sale must be within the last six months, unless no such sales are available.

For example, successful Re/Max realty agent Larry Emerson, of Colorado Springs, says, I practically do the appraisal for the appraiser. Larry is so well-prepared for the appraiser, his buyers usually have no trouble obtaining a mortgage.

But don’t mislead the appraiser. Your information will be checked from public records, local realty agents and the local multiple listing service. However, the more facts you give the appraiser, the better chances your home will appraise accurately.

5. Ask the lender to give you a copy of the appraisal. Most enlightened lenders today volunteer to give the borrower a copy of the appraisal, whether the lender or borrower paid for the appraisal. If the borrower paid, he or she is entitled to a copy.

Only if you have a copy of the appraisal can you double-check its accuracy and question any wrong result. Also, it makes a valuable record for future reference.

If you disagree with the appraised value, insist the lender have a review made or request a reappraisal by someone else. Be sure to point out specific errors, not just your opinion that the home is worth more. If the appraiser refuses to correct factual errors, such as the wrong square-footage, report the matter to your state real estate appraiser license administrator.