Hot water, cast iron radiator heat design / remodel
I’m looking for some guidance on where to go with our hot water, cast iron radiator heat. We love the radiant heat of the cast iron radiators, so not looking to switch to a different type of heat.
We have two boilers for our 130 year old 6700 sqft house. One newer boiler (7-8 years) and one old boiler that is on it’s last leg.
We’re looking for the best approach to eliminate the risk of the larger boiler deciding to call it quits in the middle of the winter. And, I don’t really want to blindly accept someone trying to sell/install a new boiler that is the same size as the current boiler as I’ve been reading up on the ‘old’ method of calculating heat loss versus the ‘right’ method.
In doing some rough math myself, I believe that our heat loss is somewhere in the 175,000 Btu/hr range. The specs on our smaller (newer) boiler state DOE HTG CAP. 127 159 MBH and IBR Water 110 138 MBH.
We currently have 3 zones (including hot water heater) on smaller boiler and 1 zone on the big old boiler (although it would be nice to break that into 3 zones).
In addition, we have heat exchangers in select rooms. Also a chimney that is not lined, so a high efficiency boiler is out of the question unless we line the chimney.
I have many questions: including whether the smaller boiler could be used to heat the entire house – maybe if it rotated through zones instead of trying to heat all zones at once? Or, if we do need to get another boiler, what is the best configuration / sizing? Are there heating consultants in my area (North Shore Boston) that I could consult with?
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