Materials
Havelock Wool Insulation: What It Is and When We Recommend It
Sheep's wool insulation explained: R-values, fire and mold testing, moisture and sound performance, cost, and where Havelock wool makes sense in LA homes.
Short answer: Havelock wool is insulation made from sheep's wool. It performs about like fiberglass for R-value, handles moisture well, absorbs sound, and appeals to owners who want a natural material in their home. It costs more than fiberglass or cellulose, so we recommend it where those benefits matter to you.
What it is
Havelock wool comes as batts for walls and floors and as loose fill for blowing into attics. According to the manufacturer, it's 100% wool with no synthetic fibers or chemical binders holding it together.
How it performs
- R-value: batts are rated R-13 at 3.5 inches (2x4 walls) and R-20 at 5.5 inches (2x6 walls). Blown-in wool is rated about R-4.3 per inch, with attic depths available up to R-60.
- Fire: Class A flame spread and smoke developed ratings under ASTM E84.
- Moisture: wool takes on and releases moisture from the air, and passes the ASTM C1338 fungi (mold) resistance test.
- Sound: the manufacturer reports a noise reduction coefficient around 0.90–0.95 at 3.5 inches, meaning it absorbs most of the sound that hits it.
When we recommend it
- Families who want a natural, non-synthetic insulation, especially in bedrooms and nurseries
- Remodels and rebuilds where walls are open and batts are easy to install
- Rooms where sound absorption matters
- Owners who've had a bad experience with itchy fiberglass
When something else makes more sense
- Tight budget: blown-in cellulose or fiberglass gets the same R-value in an attic for less.
- Air sealing: wool, like any batt or loose fill, doesn't air seal. We seal gaps first, or use spray foam where an air barrier is the goal.
- Fire-rated or noncombustible assemblies: mineral wool is the usual choice.
Does it qualify for rebates?
Most rebates are based on the R-value installed, not the material. For example, the SoCalGas wildfire rebate pays per square foot by R-value, and the LADWP attic rebate requires batts or rolls. We'll tell you which rebate fits before you choose. See 2026 rebates.
Common questions
What R-value is Havelock wool?
Havelock's batts are rated R-13 at 3.5 inches and R-20 at 5.5 inches. Their blown-in wool is rated about R-4.3 per inch, with attic depths ranging up to R-60.
Is wool insulation fire safe?
Havelock reports Class A flame spread and smoke ratings under ASTM E84, the same test used to rate most building insulation.
Does wool insulation get moldy?
Wool absorbs and releases moisture, and Havelock reports a pass on the ASTM C1338 fungi resistance test.