I wanted hydronic heating, rather than forced air. Hydronic is more efficient and more uniformly distributes the heat in a way that feels more comfortable. Hydronic heating is quiet and you don’t feel drafts or blow dust around your house. In a passive solar design, hydronic can potentially be used to store solar heat in the fluid and move it around to where it is needed.
Hyrdronic is more affordable during new construction than trying to retrofit for it later. Functionally, it goes well with my concrete floors.
There are some down sides. Without the furnace filter, dust simply settles to the floor and needs to be swept up. Randiant functions by first heating up the slab, which then slowly radiates out to the living space. The amount of mass involved adds a lot of inertia to the system, so it responds slowly to change. Adding carpets or rugs or even hard wood floors increases the resistance between the heated mass and the living space, further slowing the response time. Adding carpet could also increase the temperature of the slab, which can reduce the efficiency of the heat exchange with the hydronic fluid (heated water). This is more pronounced in warmer areas where the hydronic temperature is set to 85F rather than in northern areas where it is typically set to 160F.