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.
California attic insulation r value.
Zone 1 for example should have attic insulation of r30 to r49.
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.
Achieving greater r values in exterior walls.
You can achieve better thermal performance in your attic by adding an additional layer of insulation.
The insulation must also meet the manufacturer s specified minimum weight per sq ft.
Sacramento and most of california are in zone 3 which requires attic insulation with an r value between 30 and 60.
What i m talking about is a house with ducts in unconditioned space especially an unconditioned attic.
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.
Existing 3 4 inches of insulation.
Zones 2 and 3 r30 to r60.
Where you live different climates require different insulation r values.
State applicable energy ashrae zone minimum r value state local ms mississippi ashrae 90 1 2010.
Minimum insulation r value requirements non residential above roof deck.
In fact there are building codes that require a certain r value for insulation depending on where in the country you live.
If we put ducts in unconditioned space.
There are many ways to retrofit a home with fiberglass and.
Your home s age if your home is more than 10 year old you likely need more insulation.
Zone 4 r 38 to r 60.
Recommended insulation levels for retrofitting existing wood framed buildings.
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.
The higher the r value the better the thermal performance of the insulation.
That s where this nifty energystar chart comes in handy.
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.
As a benchmark one inch of solid wood has an r value of 1.
Batt insulation should fill the wall cavity evenly.
Add insulation to attic.
You will need a higher r value of insulation if you live in the northeast than if you live in southern california.
Our r value cognitive dissonance.
