Designed for
Retrofit:
Mini-duct Systems
with Radiant Floor Heating
By Bob Orians
No
matter when your home was built or what the physical configurations
are, you can install radiant heating along with the mini-duct system
for high performance heating cooling comfort. Crafted to weave around
and through existing construction, both systems provide a perfect
solution for retrofit applications. In fact, you’ll find there’s
little or no remodeling required. This allows you the homeowner the
unique opportunity to maintain the architectural integrity of your
home while enjoying many advantages over other systems.
Radiant Floor
Heating
One solution to home heating is a radiant floor system. These systems
run heated water or glycol through flexible plastic tubing, about
one-half to one inch in diameter. The tubes are typically laid out
in a coil pattern and evenly distributed throughout the sub-floor.
Tile, hardwood or carpeting is laid over this sub-floor and the tubing
acts as a massive radiator, heating a home from the ground up.
The benefits of
heating with radiant floor include efficiency as well as aesthetic
value. Instead of unsightly metal registers blowing hot air as with
traditional systems, creating hot spots in some areas and drafts in
others, radiant floor systems spread warmth throughout an entire home.
Getting out of bed on a chilly morning is certainly more appealing
with a warmed floor to greet bare feet. Because the radiant system
warms the objects in the room, not the air, the room immediately regains
its pleasant temperature when the door to the cold outdoors is closed.
Radiant floor heat can be controlled from room to room, so a seldom-used
guest room can be kept at a lower temperature than the family room,
bath or kitchen. Heating with a radiant floor system is also energy
efficient, as the water only needs to be heated to 90 to 130 degrees
to heat the home, producing comfortable temperatures at lower thermostat
settings and reducing heating costs.
Mini-duct
Cooling and Heating
Although radiant systems provide a comfortable home environment throughout
the winter months, the systems offer no solution to the problem of
effectively cooling a home. Therefore, a separate cooling system is
needed, the most efficient of which to pair with radiant floor heat
for overall comfort is a mini-duct, high velocity system.
A mini-duct heating
and cooling system delivers conditioned air to rooms via flexible,
2” diameter supply tubing that fits into spaces that won’t
accommodate conventional sheet metal ducting and terminates in small,
unobtrusive outlets in the walls, floor or ceiling. In addition to
the difference in supply ducting, the method of cooling with a mini-duct
system is quite different.
Conventional systems
consist of a cooling element, such as a metal coil, and a fan, which
blows air over the coil and pushes it into the room through cumbersome
metal ductwork. Mini-duct systems can provide cooling through one
of three methods: by utilizing a traditional DX coil with a refrigerant,
a heat pump coil in cooling mode or a chilled water coil. Air is drawn
across the coil with a mini-duct system as opposed to pushed, as with
a conventional system. The advantage to this method is that it actually
takes longer to move the air across the coil and, because most mini-duct
systems also utilize coils with a greater surface area, this actually
makes the air colder and can remove as much as 30% more humidity from
the air than conventional systems. This means that you can be comfortable
at higher thermostat settings, increasing efficiency and reducing
cooling costs.
Mini-duct systems
can often heat in the same way as they cool, using a heat pump coil
in temperate regions or using a hot water coil that acts as a radiator.
As in the cooling mode, air is drawn across the coil and is heated
to a higher temperature — providing hotter air to the room at
lower thermostat settings. This is significant due to the fact that,
in general, every three degrees of water temperature that can be saved
results in energy savings of 1%. When using the hot water coil, mini-duct
systems also alleviate the problem of dry air that comes with traditional
forced air systems, as the medium for creating the heated air is water.
A mini-duct cooling
and heating system, such as the Unico System, allows for flexibility
in installation. The system’s air handlers and flexible ducts
fit into tight spaces, so there is no need to drop ceilings or build
soffits or other hiding places to conceal metal ductwork runs. This
is a prime benefit of these systems in applications to both older,
architecturally unique homes and custom constructed residences.
Mini-duct systems
work on the principal of aspiration to provide even temperatures throughout
a home. Whereas traditional central HVAC systems diffuse air, a mini-duct
system provides hot and cold streams of air that is moved through
the compact tubing at a higher velocity, creating gentle circulation
without drafts, so that “even” room temperatures can be
enjoyed from floor to ceiling. The rush of air cannot be felt more
than a few inches beyond the outlet. A mini-duct system in cooling
mode also removes up to 30 percent more moisture than conventional
systems because its unique coils are colder than conventional coils,
which is especially beneficial in areas with high humidity.
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| Radiant
Floor Heating |
How They Work
Together
Radiant
floor and mini-duct systems have several of the same advantages, including
eliminating drafts, fitting neatly into a home’s aesthetics and
filling rooms with even, draft-free air. Installing them together
in a home enables the two systems to complement each other, providing
maximum indoor comfort. Because mini-duct systems are tightly enclosed
and radiant floor systems do not involve air movement, both systems
provide a high degree of air quality and eliminate the loss of conditioned
air typically experienced with inefficient forced air systems. The
mini-duct system can further increase indoor air quality when coupled
with an air purifying system.
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|
Mini-duct
system |
Radiant floor
heating is often installed in the “cocoon” of the house,
or the most often used rooms, on the first floor (i.e. kitchen, living
room and bathroom.) The mini-duct air conditioning system is used
as the primary cooling source for all floors of the house. Complementing
a radiant system, a mini-duct system with a hot water coil is used
for heating the second, third and higher floors. The home’s boiler
supplies hot water for the heating coil. The mini-duct system allows
a room to be quite comfortable at a low water temperature (a water
temperature of 120 degrees produces a room temperature of 115 degrees),
which is more energy efficient. Adding to the efficiency, heating
this way cuts down on the constant recycling of the boiler and HVAC
system. This is also the preferred method of heating in the spring
and fall months when a mini-duct system can be used to take the chill
out of the air without “firing up” the entire radiant floor
system.
Bob Orians
is director of sales and marketing for The Heating Specialist. For
more information he can be reached at 503-257-7000 or bob@theheatingspecialist.com. |
