Modular manufacturers, builders, and end users have a host of choices when it comes to indoor climate systems. This article will provide an overview of one such choice: The Unico System whole-house small duct high velocity (SDHV) central heating and cooling.
First, let’s start with a definition. As its name suggests, a small duct high velocity HVAC uses a duct system smaller than traditional forced air methods and, because smaller ducting results in less air volume, it must deliver that reduced volume at a greater speed. For the technically inclined, Unico System SDHV operates under high static pressure, with an average of 1.5-inches water column. It moves air at a speed of 1,000 to 2,000 feet per minute (FPM) at the 2-inch SDHV supply outlet with the air flow at each outlet averaging between 28 to 32 cubic feet per minute (CFM) of conditioned air.Â
Let’s break The Unico System down into its components:
1.       Indoor Air Handling Unit (AHU)
A Unico AHU typically consists of a blower, a cooling and/or heat pump coil or, in many parts of the country, a hot water coil for central heating. The Unico System has each component separate from the others in a modular configuration. This allows the system to fit better into tight spaces and eliminates any architectural compromise to the home’s design. Our sophisticated software-driven circuit board allows seamless additions such as electric heat, central humidification, connection to a hot water heating system or domestic water heating system, and high efficiency filtration (up to Hospital grade MERV 13). The only aspect that Unico SDHV shares with conventional systems is the fact that return air systems can either be singular or multiple by room.
2.       Main Trunk Ducting, or PlenumÂ
Unico plenum is available in insulated round, rectangular (3.5-inches high by 14.5-inches wide), or square sheet metal or pre-formed fiberglass constructions. In many Unico SDHV modular applications the 3.5-inch x 14.5-inch duct is installed between housing modules to supply up to 3.5 tons of conditioned air into both the module above the duct and in the module below the duct. This is a huge benefit to modular home applications as the Unico flat plenum can be installed at the factory in the interstitial space between modules. Because the Unico main supply plenum is ¼ the size of a similarly sized large duct system, 12 tons of Unico SDHV can fit in the same physical space as 3 tons of large duct conditioned air. In modular homes, space is critical.Â
3.       Supply Ducting
Unico supply ducting consists of flexible tubing that runs from the main plenum to small openings in the ceiling, wall, or floor where the conditioned air is delivered. Our supply tubing is a 4-inch OD, flexible duct with a 2-inch inner core air delivery that is designed to ensure very quiet air delivery. This duct fits in the same interstitial areas as the 3.5-inche x 14.5-inch plenum and is connected to the plenum with a leak free gasketed take off, then connected to supply tubing pre-installed in the second-floor modules.Â
4.       Outlets
In addition to our flexible supply tubing, perhaps the most recognizable difference between traditional forced air systems and Unico SDHV can be seen in our outlets. Unico System outlets are available in two configurations, round and slotted. Our round outlets have a 5-inch OD with a 2-inch ID. Our slotted outlets consist of a 1-inch by 9-inch faceplate with a ½-inch by 7-inch opening. Both configurations are available in a variety of colored plastic or wood species and can be painted, stained, or wallpapered to blend into any décor.
5.       Outdoor Unit
The Unico System is compatible with major manufactured brands of outdoor compressors, condensers, chillers, and heat pumps (air, water, or geothermal), which provides builders, subcontractors, and end users with control over their preferred method. For this reason, we do not make a specific outdoor unit, and this allows us to concentrate on making our system the very best it can be.
Why The Unico System is a Natural Fit for Modular Homes
The small, modular components of The Unico System present the following advantages for modular home manufacturers, builders, and subcontractors:
·     In-factory installation of key components
·     Fast and easy connection of pre-installed components in the field
·     An attractive, technologically advanced feature to sell to end users
·     Unico provides a team dedicated to modular home installation guidance and technical support
We’ll touch on more of the advantages The Unico System provides for makers and buyers of modular homes in future articles here at Offsite Dirt. Feel free to visit our landing page at