A difference in square footage that large needs to be addressed first to determine why such a discrepancy exist. Was additions to the home made, and if so were they permited by the local municipality. If not the property should be updated in the records which may mean going back and having permits pulled and inspections done. This would be for your benefit in that it would provide you proof that the additions meet the local building codes, which may make a difference in your insurance rates.

You really should ask your insurance agent this question. My inclination would be to insure the actual square footage.

Property records are not always up-to-date, but a huge discrepancy like that should not go unexplained. If the house truly has 1,648 sqft of actual living space (i.e., heated space), then your insurance should be based on the actual square footage. However, I would definitely ask more questions about the additional square footage. Is it all permitted space? Also, your financing will be based on the appraiser's value assessment. The appraiser compares the house you are buying to other homes that sold with similar square footage. If the the appraiser's measurement includes space that should not be included, the accuracy of the appraisal would also be affected. Last but not least, if you can't get this settled now and you buy the house, you'll have to answer the questions when you try to sell the house in the future.

You should check the City or County building department records for permits of record. This will give you a clue as to whether additions or modifications were done with building permits. If the City or County shows 966 sq. ft. chances are an addition was completed to the structure without permits. You should disclose this to your insurance carrier. In some counties, if it is not permitted, it doesn't exist and there could be coverage issues.

Ed