

In most hydronic heating systems I’ve worked on, there’s an insulated tank of hot water either somewhere in between the boiler and radiators or built into the boiler directly. The thermostats talk to valves that send the water to radiators in the rooms that need it. The boiler just keeps that water at a set temperature.
In larger buildings with really long runs, sometimes there are valves to bypass certain radiators and/or multiple tanks located around the building. I can’t say without more information about your home, but it might make sense to have one near the area you’re trying to heat most.
No storage tank at all and thermostats that fire up your boiler directly sounds very unusual and inefficient. The expansion tank you have is just meant to stabilize pressure, it doesn’t have enough volume to do much for temperature












Mine was kinda that we do if we could adjust our patterns and habits a little bit to live with the world as it is vs imposing ourselves on it. Forcing “companies” (read corpos) to do something other than maximize extraction is a big part of that