Supplemental Hydronic Boiler: Electric or…
I’m looking for advice on a supplement boiler for my 4 zone hydronic heating system. This is my secondary source of heat as for the last few years I’ve been using my LG mini split to as the primary way to heat and cool my home on Long Island, NY.
The hydronic system was originally a very old 2 zone system connected to an old oil burner. I modernized the zoning myself by splitting it into 4 zones for 3 floors (separate zone for bathrooms) with new baseboards and their own circulators controlled by a Taco switching relay with a Taco boiler reset to the old burner. This was my primary source of heat for several years before I installed the LG mini split. As a secondary system, it worked well for the coldest days and if I wanted to make the bathrooms extra toasty on a cold morning. The outdoor reset and zoning also vastly decreased my use of oil to the point a tank would last 2 years. I knew the old oil burner’s days were numbered. However it turned out the oil tank has failed first so I want to rip out the oil burner and replace it with something modern.
As I went along I modernized my home’s insulation with Low-E windows, R-15 exterior walls (most of the house is brick siding too), R-30 ceilings, at least R-60 in the attic, an insulated basement using R-10 foam and R-15 walls. I’ve done my own Manual J calculation with an estimate of 50k BTUs for my 1850 sq ft. The mini split is actually two Multi F units (30 & 34k BTU) with 4 indoor units each which I have distributed throughout the house. I am also upgrading the mini splits with drain pan heaters to allow them to heat from 14F down to -4F which should cover my climate zone all year.
I connected my hydronic system manifolds to the oil burner with couplings so it’s practically a plug and play installation to change the burner. As you can understand it’s really a standby system for the coldest days and will be called on even less with the drain pan heater upgrade. However it’s nice to reuse the existing baseboards to boost the heat in an area, like the bathrooms and to even out the heating from the mini split wall units which don’t always distribute heat as well as the baseboard does. It’s also my understanding that mini splits lose their efficiency as the temp heads below 40F so perhaps I could setup some sort of crossover between the two systems.
I’ve looked at electric boilers and the rarer air to water mini splits. I could probably undersize the hydronic boiler since it will be infrequently used, but I like the idea of it being able to handle the whole house in the event of a mini split breakdown. I would really like to just hook it up to my Taco zone unit with its existing outdoor reset.
I have an older gas hot water heater which is why I could stomach an air to water system’s expense if it could also provide hot water. I’m not really interested in a gas burner as I’ve been told I’d need upgrade my gas line and move the meter outside. Moving to electric only for utilities would also motivate me to research and install my own solar plus battery system. However, my house is a split so roof coverage is not ideal for a lot of panels. Perhaps that’s a pipe dream.
I do all my own work after meticulous research and I’ve just found myself getting stuck trying to decide how to proceed. I can share more but I’ve written quite a bit already. Any perspective is welcomed. Thanks in advance.
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