fourth year
If the bedrooms are on their own zone, then balancing cocks or zone valves can be installed to help regulate the temperatures. If the whole house is one zone or the warm rooms are intermixed with the cool ones, then the only way to regulate them is to either add baseboard in the cool rooms, assuming the system can handle the extra load, or reduce the heat in the warm rooms by removing baseboard or covering some of the fintube element to reduce the capacity.
