Modern panel radiators are already equipped with convector fins to increase the output. These radiators have fins that cover the complete length of the frontpanel. These fins are always much larger than the highest Low-H20 element, thus the contact distance between the fins and air is much longer. Hereby the air gets much warmer.
This has several disadvantages:
• the air gets dry and dust particles in the air become carbonised,
• the higher the exit air temperature, the higher the stratification. This means that the warm air goes immediately to the ceiling, where you don’t need it.
• with increasing air temperatures the air speed will increase also. The air moves between two convector fins, faster air movement causes turbulent airflow. This actually limits the output of the radiator.
In general you have to double the dimensions of the radiator when reducing the supply water temperature from 170°F to 130°F (this is approximately the point where condensing boilers become full efficiency). When doubling the volume of a panel radiator, the water content goes from two gallons to four gallons per radiator. For an installation with 10 radiators this goes from 20 up to 40 gallons. With a Low-H2O installation it goes from a quarter gallon to half a gallon. For the same installation with 10 elements this goes from 2.5 gallons up to 5 gallons. That’s 35 gallons less to heat up which results in a much faster reaction a higher comfort level and even more energy savings!