OK well, I'll chime in on our 2.5-yr old Weil-Mclain Ultra: from $400+/mo two years ago to <$300/mo the past two years during the coldest month. BUT, I did add 6" of fiberglass to our attic ($330). The Ultra is amazing because it modulates (varies it's output and changes fuel-to-air), uses outdoor reset (hotter water in colder weather) and condenses (heat recovery from exhaust, as long as your return water is sufficiently cool). The only problem we had was the Taco circulator pump that Weil-Mclain provides with the boiler died last week - but it was covered under Weil-Mclain's 5-yr parts and labor warranty on everything included with the boiler, even though technically it's not part of the boiler.
BUT - for these systems, you must have a local installer who is experienced with them. Don't trust someone who has never installed one before!
Also, remember that proper sizing is vital to efficient operation - and a (truly) modulating boiler can adjust it's output to match your needs. In my opinion, not many contractor do proper sizing caluclations - so all you need is a rough estimate with a modulating boiler.
Cast iron has much better resistance to rotting and rust thru compared to steel, from a longevity standpoint that's what I'd want in a boiler. Plus, the heating and cooling of a boiler, which generates stress, challenges the strength of a steel boiler compared to an inherent more sturdier cast iron model.
Originally posted by ross973
....also ek boiler has 10 FEET of heat exchange suface as compared to 16-18 INCHES in a conventional cast iron boiler most old school guys say steel boilers are no good does steel or cast iron have a better heat exchange?
In regards to heat exchange surface, even a pin type 'old school' boiler has lots of surface AREA that makes for low stack temps....distance the flue gases travel is important no doubt, but not the only way to extract heat.