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What type of problems can you run into when pumping cellulose into attic spaces — specifically around air conditioning units?

GBA Editor | Posted in Green Building Techniques on

i work for a green building company and lately customers been having problems with their air conditioning units. And one is even saying that they are having trouble breathing and believe that the cellulose is the cause.

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  1. GBA Editor
    Martin Holladay | | #1

    We need more details. Obviously, if you have HVAC equipment in the attic, the equipment should not be covered with cellulose insulation. Maintenance personnel need access to equipment and filters.

    Any ducts in the attic should certainly have seams carefully sealed with mastic.

    If you have uninsulated galvanized steel ducts in the attic, you wouldn't want to cover the ducts with cellulose or any other air-permeable insulation. During the summer, the lack of a vapor retarder would allow condensation to build up on the cold ducts.

    Concerning your open-ended question -- "What type of problems can you run into when pumping cellulose into attic spaces? -- weatherization workers are going to laugh out loud. The answer, of course, is "All kinds of problems." Most of these stories involve hidden chases that get unexpectedly filled with massive amounts of cellulose. Any weatherization worker can tell you a story about the time he inadvertently filled a closet (or kitchen base cabinets) full of cellulose.

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