BASC Search

Buried and Encapsulated Ducts, Jacksonville Florida

Reference

Reference investigating the strategy of using buried and/or encapsulated ducts to reduce duct thermal losses in residential buildings.

Assembled section of fiber board duct

Image

Encapsulated ducts are sprayed with ccSPF in an unconditioned attic

Image

Wrong: Ducts are held from the rafters with strapping and a large beam prevents ducts from properly lying on the ceiling plane

Image

Compact Buried Ducts in a Hot-Humid Climate House

Reference

Report on heating and cooling air-distribution ducts that are insulated, installed close to the ceiling in a vented attic and covered with attic insulation to minimize energy loss.

Right – Duct register is mastic sealed to framing

Image

Building America Top Innovations 2013: Buried and Encapsulated Ducts

Case Study

Case study describing a DOE Building America Top Innovation on HVAC ducts located in vented attics that are encapsulated in foam and buried in attic insulation.

Trunk to duct connections are only mechanically fastened and not sealed

Image

Right – Metal duct boot is properly sealed at seams

Image

Right – Flex duct is mastic sealed at junction box

Image

Right – Metal or fiberboard duct is mastic sealed at seams

Image

Still Placing Ducts in the Attic? Consider Burying Them

Reference

Information sheet about buried ducts.

Raised ceiling duct chase installation technique

Image

Measure Guideline: Buried and/or Encapsulated Ducts

Reference

Project discussing buried or encapsulated ducts and their pros and cons.

Design Options for Locating Ducts within Conditioned Space

Presentation

Presentation with technical training covering several possible approaches to locating ducts within the home’s air and thermal barriers, and then dig into design considerations and details for the spray foam encapsulation approach.

Technology Solutions Case Study: Buried and Encapsulated Ducts, Jacksonville, Florida

Case Study

Case study describing how using buried and/or encapsulated ducts can reduce duct thermal losses in existing homes.

Wrong: Duct is hung between truss members by strapping and not buried

Image

The tape is covered with mastic to ensure an airtight seal between the duct and the fitting

Image

Duct boots and other ceiling penetrations are air-sealed using spray foam

Image

Insulated floor above garage - cavity insulation with 1 inch rigid insulation with 2x2 wood furring

CAD File

Right: Ductwork is installed in direct contact with lower truss cords. In this picture the main trunk is laying on the truss cords and branch ducts are temporarily held with strapping across truss cords. Ducts are well sealed with mastic

Image

Buried and Encapsulated Ducts, Jacksonville Florida

Assembled section of fiber board duct

Encapsulated ducts are sprayed with ccSPF in an unconditioned attic

Wrong: Ducts are held from the rafters with strapping and a large beam prevents ducts from properly lying on the ceiling plane

Compact Buried Ducts in a Hot-Humid Climate House

Right – Duct register is mastic sealed to framing

Building America Top Innovations 2013: Buried and Encapsulated Ducts

Trunk to duct connections are only mechanically fastened and not sealed

Right – Metal duct boot is properly sealed at seams

Right – Flex duct is mastic sealed at junction box

Right – Metal or fiberboard duct is mastic sealed at seams

Still Placing Ducts in the Attic? Consider Burying Them

Raised ceiling duct chase installation technique

Measure Guideline: Buried and/or Encapsulated Ducts

Design Options for Locating Ducts within Conditioned Space

Technology Solutions Case Study: Buried and Encapsulated Ducts, Jacksonville, Florida

Wrong: Duct is hung between truss members by strapping and not buried

The tape is covered with mastic to ensure an airtight seal between the duct and the fitting

Duct boots and other ceiling penetrations are air-sealed using spray foam

Insulated floor above garage - cavity insulation with 1 inch rigid insulation with 2x2 wood furring

Right: Ductwork is installed in direct contact with lower truss cords. In this picture the main trunk is laying on the truss cords and branch ducts are temporarily held with strapping across truss cords. Ducts are well sealed with mastic

Fiberglass duct board typically comes in sheets 4 foot wide by 10 foot long

Measure Guideline: Reducing Thermal Losses and Gains With Buried and Encapsulated Ducts in Hot-Humid Climates

Cut-away view showing unsealed gaps around a heating duct that goes through a wall

Install wood framing cross pieces in the attic rafter bays on each side of the duct chase

Install bottom layer of rigid insulation

Insulation does not cover boot and is not sealed

Unvented Attic Insulation

Moisture Performance of Unvented Attics with Vapor Diffusion Ports and Buried Ducts in Hot, Humid Climates

Seal seams in fiber board ducts with out-clinching staples, UL-181A-approved tape, and mastic