ACHRNEWS

Web Only Exclusive: High-Velocity Cooling and Radiant Heating

August 16, 2001
The one-piece air handler fits in an attic, basement, closet, or crawlspace. High-velocity, 9-in.-id plenum duct and 2-in.-id supply tubing are common to all sizes of systems for inventory efficiency. Leftover materials can be used for the next project. (Photo courtesy of SpacePak, a Mestek Co.; all rights reserved.)
According to high-velocity cooling system manufacturer SpacePak, the following are reasons why high-velocity cooling is well-matched with radiant heating systems:
  • High-velocity cooling is easily installed in conjunction with a radiant heating system (or in a property which already has the heating system in place).
  • Narrow, flexible, preinsulated ductwork is completely concealed. Soffits to conceal bulky ductwork are not necessary.
  • Small outlets (about the size of a CD) can be installed in the ceiling, walls, or floors of each room and can be painted or wallpapered to blend with room decor. Custom wood outlets are also available for installation in wooden floors, paneled walls, or log homes.


  • Small, 2-in.-id outlets can be located in ceilings, walls, or floors, and can be painted or wallpapered to match decor. Ductwork is concealed and does not require soffits, preserving the clean, uncluttered installation provided by radiant heat.(Photo courtesy of SpacePak, a Mestek Co.; all rights reserved.)
  • Unlike a conventional system that requires a supply and return grille in every room, a high-velocity system offers a more uncluttered look.
  • System occupies 1/10th the space of a traditional system and is easier to install.
  • System fits more easily than a conventional metal duct system in homes with unusual angles; vaulted, gabled, or cut-up ceilings and roof lines; or limited space.
  • It cools more evenly without drafts (temperature variance from floor to ceiling is 2 degrees Farenheit or less).
  • An optional hot water coil can provide supplemental heat on a cold day without expending the energy to heat the mass of the radiant system. During winter, the hot water coil can provide instant heat in the morning or evening, until the radiant system reaches its optimum comfort level.
  • System removes up to 30% more moisture than traditional air conditioning, providing cooler, drier air at a more efficient thermostat setting. Superior humidity control helps preserve furnishings, artwork, etc.


  • New, oaken outlets for the SpacePak high-velocity system virtually disappear when stained to match surrounding wooden floors, paneling, and log homes. (Photo courtesy of SpacePak, a Mestek Co.; all rights reserved.)
  • System offers high efficiency (10-plus SEER).
  • Compact blower fits into a small space such as an attic, closet, or crawlspace. Some companies, such as SpacePak, offer a one-piece air handler.
  • Ductwork is pre-engineered in 100-ft continuous lengths, so it's easier to handle than sheet metal. Kwik-Connects® snap together for a quick installation and an airtight seal.
  • System components are common to all sizes of systems, making it more efficient to inventory. As with a radiant job, leftover materials can be used for the next project.
  • Vertical and chilled water units are available.
  • Publication date: 08/20/2001