Modern homes take advantage of boiler systems (circulating water instead of air) in several situations:

• In Floor Radiant Heat is a specialized system that is useful in several situations.  The two main types of in floor radiant heat include setting up a series of hot water loops prior to pouring concrete to create heated concrete floors (pictured above), or by looping water lines beneath floors of living spaces to heat them. This will not be a cost-effective solution for a wide variety of situations, but it is a nice option in select circumstances, including basements or other rooms with poured concrete floors where there will be a significant amount of time spent and a need for heat.
• Baseboard Heat is something that we have installed in certain situations.  One interesting situation was a home on Canandaigua Lake where every inch counted for the mechanicals.  Rather than installing a duct system, the homeowner opted for a combi-boiler (serves as the boiler and tankless water heater) and used the comparatively smaller pex water lines in lieu of a duct system.

While we don’t see too many folks looking to install radiators anymore, boilers still find their way into the homes we work on.