Flat Panel Radiators
Flat panel radiators are a cross between
finned-tube baseboard and radiators. There
is not as much mass as a radiator and also
fewer fins on the back side. These are typically
steel and manufactured to a variety
of lengths and heights. The steel mass adds
to the radiant energy into the room and the
fins help create convective currents.
Fan Coils
Fan coils are small convectors with fins
installed in ductwork. The hot water enters
the fan coils and air is circulated in the
home by the unit’s own fan blowing across
the fins.
Radiant Panel Heating
Radiant heating systems deliver warmth
by radiant heat transfer.
A typical radiant floor system heats the
terminal unit (floor) anywhere from 75° to
a maximum of 85°F. (Figure 14). Supply
13 National Oilheat Research Alliance
system temperature can be significantly
lower than required in a system relying on
convection. Depending upon the radiant
installation method, the water temperature
needed for heating can be as low as
100°F and up to 180°F. This difference in
temperatures can create some challenges
when working on a hybrid system, as
when, for example, the home has a radiant
zone, a baseboard zone and an indirect
water heater.
In a radiant system, the boiler is
typically at a high temperature (around
180ºF) while the radiant system operates
at a lower temperature, creating the
need for a mixing device. Mixing devices
(mixing valve, injection mixing) will send
out a lower temperature to the floor panel
system by blending the return water from
the radiant panel with the boiler water.
When a mixing device is used, there must
be a circulator after the mixing device to
insure flow through the radiant panel.
Figure 14