One of the benefits of modern hydronic heating is the ability to use multiple types of heat emitters in the same system. A common example is a heated floor slab in a basement combined with fin-tube baseboard on the main living level(s) above. When the fin-tube baseboard is sized around “traditional” design water temperatures (170° F to 200°), the system is going to need a mixing device to lower the water temperature supplied to the floor heating circuits.

Over the years, we’ve designed many systems with mixing devices to create multiple supply water temperatures for different portions of the distribution system. In general these systems have worked well, but mixing assemblies definitely add to the system’s cost and complexity. This should lead hydronic heating pros to consider if, in some applications, multiple types of heat emitters could be operated from a single supply water temperature.