You have a Buderus g124 atmospheric propane fired boiler with indirect. The AFUE rating are determined by the manufacturer of the equipment and not a factual rating of efficiency. Blue sure looks purty though... Don't get me wrong it will heat your home and hot water. I believe the poster was looking to replace an oil fired unit which is much different than gas.
What you'll find is that most installers will install what they feel comfortable installing and can care less about efficiency or whether the system is truly compatible with what you have now.
https://energykinetics.com/wp-conten...lsResearch.pdf