Builder Sprayed Insulation All Over Furnace In Attic

I found instead a vintage 3 ton ac unit with 1 rigid insulation taped all over it and insulated flex duct snaking all over the poorly insulated attic.

Builder sprayed insulation all over furnace in attic.

A plenum is the source of combustion air. This puts the furnace in at least semi conditioned space. Insulation should be rolled out perpendicular to the joists and unfaced rolls should be used. If the furnace is a fuel burning one be sure you provide air for combustion.

A lot of builders and homeowners are going with spray foam insulation because of the airtightness benefits. If the builder says that will cost more then use the money you would have spent on the foam insulation and attic enclosures to do this. Gable vents and soffits are the big culprits here. If you don t have a crawl space or a basement then it can be a challenge to place a furnace on the ground floor of the structure.

The attic is the worst place to install hvac equipment and duct work. A furnace in the attic is a design that works for all homes. In a proper spray foam job a contractor doesn t just spray foam all over the top of your attic and go home. Most often the attic is sealed by installing spray foam insulation at the roofline thus bringing the attic inside the building enclosure and turning it into conditioned space directly or indirectly.

The rigid insulation was saturated from condensation. Batt or rolled insulation or blown loose fill insulation fiberglass or cellulose can be installed on top of old insulation. Otherwise humidity will quickly creep into your attic. The attic floor needs an insulation value of r30 40.

She asked me to go into the attic to find the roof leaks or where the snow is blowing in through the soffits. If the air is not piped in directly to the furnace the attic space would be considered the plenum. You might not receive the same air movement benefits if the unit is in a garage either. But then the questioner mentioned that the spray foam contractor had intentionally left big holes to the outside by not sealing the gable vents.

A case of incompatibility. If you pipe the air in directly to the furnace and it does not use attic space air then you can use sprayfoam. You can build a small enclosure around the furnace with rigid foam insulation then pick up the insulation on the ceiling inside the enclosure. Any existing batt or roll insulation in the attic should have the facing against the attic drywall floor or no facing at all.