with forced air the heat ends up at celing level first ( where yioure not hanging out ) then works its way down to where the T stat is. Humans generally are most comfortablle at 72' but with forced air you have a more difficult time achieving perfect heat as the heating curve of FA does not Match the heating Curve of the human body, with H20 it is almost identical.
Forced air uses convection as mentioned.
Hot water uses Radiant heat.
When you have air changes 4 complete air changes every 24 hours if memory serves ( Code ) FA loses much of the heat caus e the air gets dispelled. in H20 systems radiant heat ( heating object and not the air between ) does not lose its energy when air changes occur. it also brings the heat down to a level where you feel it more ( our bodys heating curve is close to water heating curve because we are mostly water, not air
This is why commercial Car washes and such use Radient heat systems, otherwise they would lose all their heat when someone opens the bay door.
h20 more expensive
And the above mentioned things. you are on a good site to learn much, stay on here and let us know how you do..
Interesting note. there is something called the "cold 70's " this occurs when you are near a cold surface ( imagine drinking a coffee ner a large window on a winter day ) the chill you experience is because you are losing heat to the windowpane. remember these 2 things
1. there Is NO SUCH THING AS COLD, only an absence of heat.
2. heat must move towards or occupy a colder space.
and just for complete randomness of info. The human body releases 400 btus of heat ( 1, 680 joules ) at rest every hour.