What i m talking about is a house with ducts in unconditioned space especially an unconditioned attic.
California attic insulation r value.
You can achieve better thermal performance in your attic by adding an additional layer of insulation.
Zone 1 for example should have attic insulation of r30 to r49.
You will need a higher r value of insulation if you live in the northeast than if you live in southern california.
That s where this nifty energystar chart comes in handy.
In comparison an inch of blown fiberglass insulation has an r value of 3 1 3 4 and an inch of blown cellulose in an attic has an r value of 3 2 3 7 along with knowing the r value of a particular insulation it is also important to calculate the r value of a total system.
As a benchmark one inch of solid wood has an r value of 1.
And zones 5 through 8 need r49 to r60.
Zones 2 and 3 r30 to r60.
Your home s age if your home is more than 10 year old you likely need more insulation.
Our r value cognitive dissonance.
State applicable energy ashrae zone minimum r value state local ms mississippi ashrae 90 1 2010.
I m in georgia iecc climate zone 3 where our current state code requires r 13 in exterior walls r 18 in attic kneewalls r 19 in floors and r 30 in ceilings.
Batt insulation should fill the wall cavity evenly.
Recommended insulation levels for retrofitting existing wood framed buildings.
If we put ducts in unconditioned space.
If kraft or foil faced insulation is used it should be installed per manufacturer recommendations to minimize air leakage and avoid sagging of the insulation.
Insulation leakage radiant barrier r 30 at ceiling attic floor r 38 at ceiling attic floor fiberglass below roof deck between rafters air handler ducts in the attic option b 1 r 6 or r 8 depending on cz all with 5 leakage 2 3 5 7 10 16 r 13 4 8 9 11 15 r 19 air handler ducts in conditioned space option c 1 16 r 6 all with 5 leakage.
For the corresponding r value.
Achieving greater r values in exterior walls.
Existing 3 4 inches of insulation.
Minimum insulation r value requirements non residential above roof deck.
Zone 4 r 38 to r 60.
As you can imagine the r value for insulating an attic in alaska isn t necessarily going to be the same for insulating an attic in california.
Add insulation to attic.
3 r 20 4 r 20 state only ca california 2016 building energy efficiency standards 2 r 25 3 r 25 4 r 30 5 r 30 6 r 30 state local co colorado 2012 iecc 4 r 25 5 r 25 6 r 30.
Sacramento and most of california are in zone 3 which requires attic insulation with an r value between 30 and 60.
There are many ways to retrofit a home with fiberglass and.
The insulation must also meet the manufacturer s specified minimum weight per sq ft.
