Prices may not be the lowest here, but a good place to get some ideas is centralboiler.com There you can view/print their full accessories catalog. They have several different models and sizes. For example, there is a 50k btu heat exchanger which you can get a cabinet for complete with fan. Looks like a floor model. Others hang. There are wall mounts of several sizes, some just convection. I'm heating greenhouses with 140k btu heat exchangers installed into my existing oil-fired furnaces using fan relays. Works great!! Note that having a higher btu rating than needed is not a bad thing, just means it will heat the area quicker. Just my thoughts. Definitely worth hooking it up to the boiler though. Electric heaters are ridiculously expensive to run.