I am a skilled DIY'er so its not for everyone. And My dad had a friend who did a bunch of plumbing to assist.....but I replaced a hot air system with a complete hot water system, boiler and all. Later I installed an indirect water heater. I guess my point is, the install/replace should not be a big deal for a guy who does that for a living. Only thing these days there might be some permitting that might cause some more work.