Machon Ot, the foremost experts in the field, will visit your synagogue where they will evaluate your sifrei Torah based on the various characteristics of each one. By examining the type of klaf used (and its manufacture) they will be able to determine its country of origin. The composition of the ink (whose halachic restrictions, permit some flexibility), as well as the writing style employed, aid in this determination too. Together the above factors are used in its historical placement, and ultimately its appraised value.
The factors that determine the value of a Torah include both the issues listed above, in addition to the condition of the Torah. The condition of the Torah is based heavily on the status of the ink and the klaf (parchment), how well it has withstood the test of time. Other factors include its basic quality, even at the time it was written. Did the sofer possess a high degree of expertise, or was he a novice? What was the original quality of the klaf? The poverty in some countries often affected the quality of he klaf, as a poor society was unable to feed their animals very well. These factors among others help determine the value of your Torah. Often synagogues have insured their torah scrolls for amounts that greatly exceed their replacement value.
A new Sefer Torah can cost as much as $35,000. This is acceptable and can be a legitimate value. However, many older Sifrei Torah are of little monetary value. When they are not kasher, the procedure of making them kasher may be much too costly. Often we will find that synagogues have greatly over insured their Sifrei Torah. Your synagogue’s insurance premiums are based on these values. It makes no sense to insure a Sefer Torah that has little value (eg. $100.00) for $25,000. This is commonly found in many synagogues. Our appraisals are current and accurate. The real value of a Sefer Torah is based on the cost of purchasing a similar Sefer Torah of equal size, weight and quality.
Sometimes we have been surprised to find a synagogue that has underinsured specific Sifrei Torah that have specific historical or museum quality significance. We have found Sifrei Torah valued as high as $50,000 as they are part of our historical legacy.