While each room can be equipped with a radiator sporting its own TRV, there are scenarios where an owner wants to control each floor of their home with a different temperature.  This is where we introduce an alternative heating distribution system called zoning, incorporating a thermostat for each floor of the house, and a valve which that thermostat controls is usually situated downstairs in a mechanical room. When a basement wants heat, this valve opens up and sends heated water to the basement radiators or to the radiator floor, or whatever the case is, independent of what the rest of the house is doing.

A lot of people like the zoning system for multi-unit residential applications; they want to rent out their basement, but not necessarily to share the same temperature with the tenant. The solution – they zone the basement, already armed with its own thermostat.  All the radiators in the space will be at the same temperature, but the basement space itself will have control from the rest of the house.

IS ZONING THE SOLUTION TO MIXING STEEL WITH CAST IRON IN THE HOME?

If you wanted to put an addition on your home and use steel radiators, you would zone it separately than the rest of the house. You’d put its own thermostat in there, install the steel radiators as the addition, and separate it at the boiler, and it would operate as two completely different systems in your house.

The old original part of the house with cast rads would have its own thermostat, and the new addition with the steel rads would have its own thermostat, and the two will operate independent of each other and keep their spaces at the desired temperature.