All of this is to point out that the moisture is independent of the heating system be it radiant or forced air neither of these is wet or dry just hot or cold until you add or remove moisture.
Now, further on you'll learn that there is no heat in radiant just electromagnetic energy.
When designers use exclusively a furnace to move ventilation air, the ventilation air efficacy is a function of the on/off cycles of the blower. If air movement were a prerequisite for thermal comfort you would feel cold while sitting in the sun on a calm day..that makes sense to you?
When the blower is on it is good when it is off it is less good translation: if the indoor air quality system in your home is rendered useless by controlling thermal comfort it is IMHO dysfunctional. Of course not.....there were so many unbelievable statements at this e How article it's easier for us to advise readers to avoid any article that mentions 'polyurethane' pipes and 'floor furnaces' in the same breath. We find the syntax in the internet statement interesting..this link for heat transfer coefficients (HTC)..difference between HTC values is based on the differences in convection, and the amount of convection is a function of the enclosure performance, room geometry and surface temperatures and orientation of the radiant panel (wall, floor, or ceiling).
So what radiant systems do is enable the use of balanced 100% dedicated outdoor air systems such as HRV/ERVs.
Such systems have the highest efficacy of all ventilation systems. Air movement it is not a prerequisite for thermal comfort.
Describing radiant heat as dry would be like saying energy is dry.
There are no units in science to describe radiant as dry.
The aggressiveness of natural convection and stratification is a function of the building enclosure, radiant panel orientation (wall, ceiling, or floor) and whether it is heated (energy emitted) or cooled (energy absorbed).
Ok sometimes people use wet heat vs dry heat to compare systems using water, aka hydronics or without water, aka forced air or "electric" but in this case they are referring to the absence of moisture.
The thing is - heat is a form of energy, moisture and air are not - they are mass.
Both locations are heated with radiant from the sun so using the incorrect logic of "radiant heat is dry heat" - how can this be when clearly conditions exists in Hawaii where it is wet?
So now do you see why radiant heat in of itself cannot be described as dry?
Since 2004 this single article has caused more tightly wound up individuals to explode/implode than any other thing I've written.