To answer the above question you need to understand how companies arrive at the premiums they do... years ago a concept called PREDICTIVE MODELING came into existence and people and their property were being rated based on a complicated algorithm that is constantly changing to improve the profitability for the insurance company based on every individual customer and no longer a population of customers...
So, even if two families with identical houses and identical cars with identical income live next door to each other the premium they pay will be different. This happens because their insurance score is different, driving records are different and claim history is different and we can go on and on.  The algorithm is complicated and I will be the first to admit that we have no idea as to which company any one customer will fit in to.
Now, add to the above the fact that each company has a different algorithm and a different profit structure and a different loss ratio(money they take in to money going out) and when it all comes into play the premium gets adjusted...
On any given day one customer, on a 250k home could have a premium quote that ranges from $700 to $3000.  So at that point one would say go with the cheapest.  Not so fast!  not all policies are created equal as one of my customers can attest too.  When a house burns down, you don't ask how cheap it is .. you ask how much coverage do I have... This is where it becomes very important to know what you are buying...
Bottom line is to work with an independent agent who has access to multiple companies and knows the differences in coverages... when an insurer needs to make a profit and the investment strategy they use is not working for them then they have to adjust somewhere.  Its business, not personal and as a consumer you are left with a choice to make... That is where a good independent agent is important...  a low premium up front is not the cost of insurance... the cost is when a claim is not covered.

The reason old houses are harder to insure is for many factors… insurance companies do not want or rather prefer not to be on the hook for older homes because they are considered at a higher risk for losses…

Most insurance companies prefer homes that are 35 years old and newer because there is a better chance that the plumbing is current, meaning PVC and copper pipes.  The heating units are more modern with current code parts… the roof of the home is more likely to be in good shape… and less likely that the home will have lead paint, as well as the electric components of the house are more updated to current codes as well.

If a home has been completely remodeled and was built in 1900 to 1950 there are insurance companies that will write that house but will also make sure to rate for whatever the house is lacking in, and therefore will be cost prohibitive for the client.

Recently I had two homes to insure…a home that was built in 1920 which had everything remodeled but the garage had issues the companies would not like, so therefore it did not get a competitive rate… the other home was built in 1900 and some deficiencies were found on the property that could be dealt with but the company rated the home high, so again not a competitive rate…

Compare that to a home built in 1975 or 2002 that is completely up to date on everything, the clients saved 50% from their previous insurer…yes, 50%! They went from 4200/year to 2100/year with better coverage.  Does that always happen?... NO!… but very possible.

Why the discrepancy… see my next post.