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.
Spray foam insulation attic with furnace.
Heat rises and much of the heat your furnace or fireplace puts out into your home can escape into the attic and out through the roof of your home.
Compared to traditional insulation whether fiberglass or cellulose spray foam has the potential to provide better performance via its air sealing properties high r values per inch of thickness and in the case of closed cell spray foam ability to repel moisture.
To combat that a combination of spray foam and or batt insulation can be installed to keep heat in and reduce energy bills.
What does hvac have to do with spray foam.
Nothing unusual about that.
The good news is that some installers understand this problem and seek to address.
Oh and when you put it in your attic spray foam.
Earlier this year i got a question about a home that had spray foam insulation in the attic.
High r value six per inch for closed cell air barrier no sagging so no air gaps air tightness 0 10 to 0 20 air changes per hour high shear and compressive strength when bonded to facing materials.
Many homeowners love spray foam insulation and it s easy to understand why.
However in a traditionally insulated attic insulation on the ceiling the attic is vented.
When we seal the attic with spray foam it s as tight as a butter tub.
A lot of builders and homeowners are going with spray foam insulation because of the airtightness benefits but then the questioner mentioned that the spray foam contractor had intentionally left big holes to the outside by not sealing the gable vents.
One huge benefit of the spray foam insulated attic is that conditioned air leakage from the ac furnace duct system is contained and used to condition the attic.
A while back i wrote about the incompatibility of putting an atmospheric combustion furnace in a sealed attic 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.
You can downsize hvac equipment which will save you money when purchasing and operating the equipment.
A while back i wrote about the incompatibility of putting an atmospheric combustion furnace in a sealed attic.
With spray foam because it is both an air seal and an insulation it simply works better than other types of insulation.
Spray foam insulation for attics.