Havelock Loose Fill Wool Insulation

Loose fill insulation is increasingly preferred amongst industry leaders in the built environment. Havelock Wool loose fill insulation is widely used in residential and commercial construction applications that require superior thermal, moisture and acoustic insulation.

We produce our loose fill following a proprietary and repeatable manufacturing process. This yields knops, or balls, that enhance our wool’s ability to trap increasing amounts of air. This process accelerates wool’s inherent characteristics and allows us to exceed the R-values of all other insulation mediums except the most toxic: spray foam.

loose fill wool insulation

loose fill insulation

What is Loose Fill Insulation?

Loose fill or “blown-in” insulation is a more recent entrant into the insulation market. Installation begins with a membrane placed over open stud bays, or a hole poked in an existing wall, and insulation is blown behind.

Traditional batt insulation “slumps” overtime. This creates air gaps and a drop in insulation R-value. Loose fill insulation prevents this by filling your wall cavity more completely.

Loose Fill Insulation Benefits

Our product is all-natural, renewable and sustainable in it’s production, while being compostable at the end of an extended useful life. Wool is inherently self-extinguishing and manages moisture against 65% relative humidity. Our loose fill out performs most other types of insulation with an R-value of 4.3 per inch.

loose fill insulation

Easy Installation

loose fill insulation

Outperforming R-Value

loose fill insulation

Unparalleled Health & Safety

loose fill insulation

Passive Filtration

loose fill insulation

Moisture Management

loose fill insulation

Sound Absorption

Loose fill insulation can be installed by hand though pneumatic blowing is recommended. There are various machines fit for installing wool.

This video covers all aspects of loose fill installation: tools and materials needed, job site preparation and technique.


Click to the left for a quick view of DIY install methodology.

Composition & Materials

Our loose fill insulation is comprised of 100% wool and no synthetic mix. We make small balls which are hugely effective at trapping air, while avoiding slump once installed. Some argue that entangling a straight fiber will actually allow it to expand over time. Irrespectively, the extra trapping of air allows for higher rvalues to be achieved.

Technical Data

Compliance: California Bureau of Thermal Insulation: License #T1500 / Registry #CA-T500

Physical Properties:

havelock wool insulation


Surface Burning
Fire Hazard
Thermal Conductivity

havelock wool insulation


Smoke Developed (Class A)
Resistance Value
Flame Spread (Class A)
Sound Absorption Coefficient

havelock wool insulation


ASTM E-­84
ASTM E-­84
ASTM C-­518
ASTM C-­423

Absorption Coefficients *

125 250 500 1000 2000 4000 NRC
0.73 1.01 0.90 0.91 1.01 1.01 0.95

*The Noise Reduction Coefficient (commonly abbreviated NRC) is a scalar representation of the amount of sound energy absorbed upon striking a particular surface. An NRC of 0 indicates perfect reflection; an NRC of 1 indicates perfect absorption.

Coverage Chart

The following thermal performance values are achieved when insulation is installed at the thickness, weights and coverage specified.

R Value Bag Requirements Max Coverage Minimum Weight Minimum Installed Thickness
To obtain thermal resistance of: # of bags per 1000 sq ft Contents of bag (25lbs) shall not cover more than: (sq ft.) Weight per sq ft shall not be less than lbs / sqft: Minimum thickness
7 6 162 0.15 1.5
8.5 7 134 0.19 2.0
11 10 103 0.24 2.5
13 11 87 0.29 3.0
15 13 76 0.33 3.5
19 17 60 0.42 4.5
22 19 52 0.48 5.0
24 21 47 0.53 5.5
26 23 44 0.57 6.0
28 25 41 0.62 6.5
30 26 38 0.66 7.0
38 33 30 0.84 9.0
40 35 28 0.88 9.5
41 36 28 0.90 9.5
43 38 26 0.95 10.0
45 40 25 0.99 10.5
47 41 24 1.03 11.0
49 43 23 1.08 11.5
52 46 22 1.14 12.0
54 48 21 1.19 12.5
56 49 20 1.23 13.0
60 53 19 1.32 14.0
100 88 11 2.20 23.0

Connect with the Havelock Herd

It is our goal to produce a truly superior building product with unrivaled integrity. We work exclusively with those who appreciate alternative building products and a healthier, more sustainable ecosystem. We are actively building consumer awareness concerning conventional toxic building materials.

loose fill insulation