In the old days, the standard estimate was $4 per thousand. However, since 2001, that has gone out the window. There are many variables that did not come into play a few years ago. Replacement cost on older homes will require a higher premium than for newer homes. Log homes tend to have higher premiums due to the nature of fire damage and repair costs. Homes in the country tend to have higher premiums than those within a municipality with fire protection nearby.
The only true way to get an accurate estimate is to get one from an insurance professional who may or may not need to do a visual inspection. As a mortgage professional, I tend to estimate higher than I may need to, but I always adivse clients that the only accurate way to find out how much insurance premiums will be is the obvious one—via an insurance agent.