Need thoughts regarding propane boiler install

Apologies in advance for too much information. I feel like I need more opinions about a difficult situation.



I need to replace our boiler, a 20+ year old oil-fired model which has many problems. We live in a cold winter climate and the boiler is used for both baseboard heat and the hot water, so it gets a lot of use in this 2500 sqft open floor plan house. The boiler currently lives in the garage, which is both large (2+ car) and unheated. This house was not built with the intent of housing a boiler -- it was built in the 1970's with electric heat, and a previous owner retrofit the house with the oil burner.



The current garage location is not ideal both because it is an unheated space and because you have to be careful when parking the car to leave space not to bang into the boiler.



For various reasons I wanted to take the opportunity of a new boiler to switch to propane fuel. I consulted with someone who I believe to be an experienced HVAC guy and he said that the replacement should be fairly simple, basically cutting out the oil boiler and cutting in the propane boiler, maintaining most of the existing infrastructure. He sold us a Peerless propane boiler and quoted us a seemingly low price for the install; but he never did the install. Instead, he disappeared, and stopped returning calls.



Meanwhile, the propane company set their tank and ran a supply line in anticipation. After months of frustration not hearing back from the HVAC guy to complete the install, I finally went elsewhere, to a company contracted by the propane supplier (the propane supplier is a full service supplier so they are not wedded to promoting propane, they also sell oil).



When the new guy came to assess the situation, he found a number of problems with the "simple swap" plan. These include:



- The oil boiler is set on the floor, but he says a new boiler needs to be at least 2 feet off the ground (concrete).



- The unheated garage is a poor environment for a propane boiler. Supposedly the condensation produced by combustion is liable to freeze and cause ignition problems. Note that it is often below freezing in the garage during the deep winter, and sometimes even below 0F.



- The unobstructed location of the oil boiler would be a code violation for a propane boiler, because it could be struck by the car. He says that the propane boiler would either need to be separated from the car area by a wall (such as a room-within-a-room), or by pillars 4 feet from the boiler, which would effectively prevent parking in the garage.



For these reasons (and more), he feels that a direct swap is not only not a good idea, but would not be a legal install. Among the options he suggested for an "ideal" install, albeit costly, would be constructing a little room within the garage that could be insulated and the propane boiler relocated to that room. Another idea is to build a small shed/extension off the garage, again insulated, and move the boiler into there.



A third possibility is to give up and replace the oil boiler with a new oil boiler. In this case, he says he would be in a better position to swap in, although there are still some issues like the height off the floor, and heat loss running in the unheated garage.



There are other factors, too; for example, he says that right now we have a lot of anti-freeze in the line (due to pipes running through the unheated garage) and that this reduces the heat carrying capacity of the baseboards. He says that if the boiler (either propane or oil) were in an insulated mini-room then he could reduce the amount of anti-freeze in the system and improve heating efficiency.



So many factors to consider. Of course it is not cheap to build a room, and building the little room within the garage would require significant re-routing of the existing zone pipes, which he says would add up to a total install cost around $5K. Believe it or not, the original guy who disappeared wanted $750 for the "swap" install.



I don't know how useful this is, but attached is a photo of the old installed boiler beside the new propane boiler.



I am interested in any and all opinions on my situation. Do the issues flagged by the new guy sound reasonable? Or is he looking for extra cash? Was the original guy's swap idea indeed naive and/or downright illegal? Should I ditch the propane plan (which would mean trying to unload the $3K boiler we already bought) and instead just get a new oil boiler? Any other thoughts I'm not considering?



Thanks for everyone's time and again I apologize for going on so long. I would be happy to provide any more information if it would help advise.