In a vented attic this can happen when the duct is in close proximity to conditioned space i e the ceiling and also thermally isolated from the hot attic beneath the ceiling insulation.
Add insulation to attic ducts.
How much does attic insulation cost.
Pull down stair or ladder.
Learn more about this important step here.
If your rigid metal ductwork has any insulation it may already have enough.
Measure the depth up to the top of the ducts.
Then check on the recommended depth for the cellulose insulation planned for the attic.
The remaining 2 tons of capacity is at least 1 5x oversized for the actual 1 load.
The duct insulation should include a vapor barrier cover.
Add additional sealant if necessary.
In more cases than not a 3 ton ac with the ducts in the attic has a ton or so of load that s just from the location of the ducts in the attic and the associated duct gains leakage etc.
You need insulation even around your ducts no matter where you live.
The cost and effort to add more insulation is minimal.
Mechanically fasten and mastic seal all duct connections.
Use the type of.
Attic hatch or door.
Don t use standard cloth duct tape on hvac ductwork since the adhesive won t hold up to extreme temperatures.
The pros charge 1 500 to 2 000 to do a 1 200 sq ft.
You can do it yourself for about 500.
If you need to add insulation in your attic save big by blowing in cellulose insulation yourself.
The problem with uninsulated ducts.
Install loose fill insulation to cover the ducts and the attic floor to meet or exceed the code required r value for attic insulation.
If your attic has enough insulation and proper air sealing and your home still feels drafty and cold in the winter or too warm in the summer chances are you need to add insulation to the exterior walls.
This is more expensive and usually requires a contractor but it may be worth the cost especially if you live in a very cold climate.
When it comes to adding duct insulation your monthly savings in utility bills will soon cover the costs especially if you install the insulation yourself.
Insulation isn t only about keeping heat in.
When insulating hvac ductwork use a foil faced fiberglass insulation with an r 6 or higher r value.
Blown in insulation overview.
Add weatherstripping around the perimeter and a sweep to the door of a walk up attic.
Consider adding more insulation as ductwork is farther from the furnace.
For an added layer of protection you can apply duct mastic to the tape and duct.
Check with your installer or manufacturer s website or bags to find the recommended depth 2.
Test total duct leakage.
If you want to cover metal ductwork.
In this case the temperature gradient between supply air and the ceiling can be such that the duct surface could be cooler than the local dew point.
Affix rigid foam insulation to the attic side of the hatch or door.