Masonry heaters are radiant, conductive and convective heaters. Unlike a regular wood stove, the heat is gentle and moves by a combination of passive convective flow created by the interior contraflow design and the radiant heat emitted like rays of light and heat from the sun as well as with conduction when you touch it. This means, once a fire is established in the firebox, smoke and flame then travel up the central fire tube core to the top of the heater, then separates evenly and travels down both sides of the heater walls, cooling as it falls.
Due to it’s large mass the heater can warm large amounts of air causing it to rise or float above the cool air which moves toward the heater to fill the void left by the warmed air. This cycle a gentle, balanced airflow in the room – also known as convective heat flow. If you stand next to the heater or ten feet away from it, the heat is the same due to both the convective airflow and the radiant heat which transmits as rays instead of heated mass. But that all pales in comparison to sitting on or laying on the bench after a winter outing and soaking up the heat through conduction and all the rest too!
In essence the radiant heat warms that which it can see and the convective flow can help warm more remote areas of a house like bedrooms which cannot see the heater as long as air is free to flow between the rooms including between levels. These remote and therefore cooler areas of a home are where you’d normally bundle up in bed to conserve your own radiant, conductive and convective heat by insulating yourself with blankets.