Please see below.

I live in a house that is about 120 years old. It has a hot water heating system that is about 85 years old but is a very simple and robust system. It was originally coal fired but was converted to natural gas in the 60's. It consists of a cast iron boiler (it's not really a boiler as it only heats the water to about 180 degrees), steel piping and the old cast iron radiators. A couple of years ago, my insurance company wanted an inspection done on it so I hired the best ticketed gas fitter in the area to inspect it. He was retired at the time but still had a valid ticket so he could do the inspection. He had also maintained the system over the years so he was very familiar with it. H wrote a report saying what he inspected and what the condition was of every part of the system. He also gave me a description of how the system operated and why these systems last forever. I took the report to the insurance agent confident that everything was good. The insurance company didn't accept the report because it wasn't on company letter head even though he is licensed and ticketed. I went to another plumber who used his report and put it on letter head and now the insurance company wants the boiler replaced before they will insure me. My agent found a new company who will insure me but they want $500 more per year. I felt that I have no choice but to pay that this year and grudging replace the boiler. I would have a more efficient system so it makes sense but before committing to a major expense, I asked if I would have to replace the radiators. The answer is yes. So now I have to replace the entire system, a job that will cost $30,000 to $40,000. I have to replace a system that will operate safely and last for many more years with a more efficient system that has a life span of 20 to 25 years. For about $5,000 I can make my existing system almost as efficient as a new system. How can I get the insurance company to understand this?