Do your homework on the mod/con. Especially when using propane for fuel. Propane leaves more residue than natural gas and by their very nature most mod/con boilers have very small passage ways between the sections or tubes in the heat exchanger. These plug up in normal use and MUST be cleaned at least annually. We're talking remove the burner, apply chemical cleaner, soak, brush out, more than likely repeat if you let it go to long, then rinse out with clear water and reassemble.
Good ones are the Prestige series made by Triangle Tube, and the Vitodens from Viessmann to name a couple. Avoid anything with a heat exchanger made by a French company named Giannoni.....like the plague. A lot of the less expensive units/brands on the market use that heat exchanger.
Some manufacturers are using aluminum for their heat exchanger material and for me the jury is still out on that. Aluminum in contact with corrosive condensate, corrosive combustion byproducts and flame temps of 1700*+............Just doesn't "sit" good with me.
Expect to see the price for one of the two brands I mentioned in the $4-5,000 range for the boiler alone.
If you have a wood stove to take the edge off your fuel consumption I would want to do some math for you on payback for a mod/con vs standard boiler if you were my customer. The old cast iron type will outlast ANY M/C boiler by a 2-1 margin so when you factor that into the equation along with your wood stove I kinda scratch my head when I put myself in your shoes.
Of far more importance than the boiler itself is the skill and knowledge level of the installer. You and anyone else for that matter need to understand that efficient hydronic heating is influenced more by the piping, control and installation than by the boiler itself. This goes for wood or pellet fired boilers too.
Unfortunately, in a lot of areas, hydronic heating is a lost or dying art and finding someone who is a real live heating professional rather than just a plumber who puts piping together and a challenge. I would encourage anyone thinking about buying a boiler (of any fuel type) to buy John Sigenthalers book, Modern Hydronic Heating and hang around on the "Wall" at
www.heatinghelp.com to become knowledgable enough to spot an installer who doesn't know jack about what he is doing.
Well after studying the situation for a few years about wood boilers I've come to the conclusion they are not for me.The house is 1400sq., ranch, on a full basement. I have a mod con I would not trade for the world and went with a wood stove for suppemental heating. For me I have the best of both worlds. The house is seven years old and tight. The envelope is by far the most important item in heating . I have the room and storage space(not in the house) for a wood boiler but the money and time for a wood boiler could not be justified. Call me crazy,Love boilers, but a wood fired one sorry. Love watching the fire in the wood stove from the comfort of my recliner.
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