Radiant Panel Baseboard Heating
Not so long ago radiant panel baseboard heat was referred to as the “poor man’s
radiant heat.” Today, the old fashioned, conspicuous, rust prone heaters of bygone
days have been replaced with décor friendly panels less than 1” wide that closely
resemble the look of traditional baseboard trim.
Radiant heat by nature maintains a consistent floor to ceiling temperature throughout
the room without consuming beneficial moisture from the room air.
And, since radiant heat doesn’t require a fan to distribute heat there is no wall
discoloration around the heating vents and dust particles are kept to a minimum.
Radiant Baseboard Panels
The panels come in various sizes ranging
from 18 inches to 8 1/2 feet.
Attached to the back of each panel are two
copper lined aluminum tubes.
One supplies the heated water and the
other returns it to the boiler for reheating.
The panels snap into brackets screwed into the wall and are connected with PEX
tubing to form a single loop for each room. However, larger spaces may require more
than one loop.
Filler panels are installed in the gaps between the heating panels to give it the look of
traditional baseboard trim.
The heating panels are priced according to length with an 8 foot section costing
Determining Heating Requirements
The number and length of the panels required is determined by the heat loss
calculation. The heat loss of any given area must be replaced with the heat output
from the baseboard radiation.
The amount of heat a radiant panel will produce depends on the water temperature
and flow rate. For example: One linear foot of radiant panel with 180º F water flowing
through it at a rate of 1 gallon per minute produces 220 BTU’s per hour.
If the heat loss calculation for the room is, let’s say, 3,700 BTU per hour you would
need 17 linear feet (3,700/220 = 16.81) of radiant baseboard to heat the room.
The more baseboards you install, the lower the water temperature your system will
require. This will provide maximum energy savings and comfort levels. As a rule you
save 1% of fuel for every 3 degrees you lower the delivery water temperature to your
Piping the hot water from the boiler to the panels
Pressure drop calculations should be performed to determine the proper pipe sizes.
Due to the small inside diameter of tubing recommended by radiant panel
manufacturers the flow of water could be restricted. Because of this the maximum
length of supply and return lines combined is 120’ for PEX and 160’ for copper.
If the total runs exceed the limits a manifold must be placed in a remote location,
closer to the room such as a closet or pantry to reduce the length of pipe.
Another alternative if a run is to long may be to use a larger diameter pipe for the main
lines to and from a room or zone which is then reduced to either 3/8” copper or 12mm
PEX before the come up through the holes in the floor.
After the total numbers of panels has been established, the remaining components can
be determined. Pipe sizes, components types, and quantity of zones will vary
according to system size and design.
Many different types of water heating appliances can be used with radiant baseboard
panels - it depends on system size and whether or not domestic hot water is included.
Common boiler types include indirect water heaters, tankless water heaters, combi
boilers that provide both heat and hot water and the new high efficiency modulating
Another alternative is the condensing boiler. The major difference between a
condensing boiler and the others is operating temperature. Condensing boilers
operate at a lower temperature to ensure the water returns to the boiler at less than
130º to condense the flue gases. If the return water temperature is too high the flue
gases won't condense and fuel efficiency is lost.
(See also the article: Best High Efficiency Condensing Boilers)
A small, low wattage water pump used to circulate heated fluid through tubing in a
radiant system. It should be sized based on the required flow rate and pressure drop
of your system.
Most often a factory built manifold that contains the circulator pumps, ball valves, check
valves, in line thermometers, pump flanges, drain valves, and all the plumbing
hardware necessary to effectively distribute heated fluid to multiple heating zones.
A device used to supply a consistent, lower, pre-regulated water temperature to a
radiant system. Mixing valves are most often used in conjunction with high
temperature boilers, many designed to heat water to temperatures in excess of 160
Outdoor reset controls use outside air temperature as the basis for determining an
ideal "target" water temperature to be supplied to the system's heat emitters. The
goal is always the same: To maintain the rate of heat delivery from the heat emitters
equal to the rate of heat loss from the building. In short, it's like adding cruise control
to the heating system.
Boiler Room in a Box
The alternative to purchasing individual components is a system called "Boiler Room in
a Box." As the name implies, all of the of the heating and distribution components
arrive pre-assembled in a box (crate) and are ready for immediate installation with a
minimum number of hook ups. Each system is designed to match the exact
specifications of individual heating systems.