What is Wood Fiber Insulation, and Why Haven’t You Heard of It?

When it comes to insulation, you’ll often hear two schools of thought:

1. “Just give me something that works.”

2. “If I can improve performance or sustainability, I want to know about it.”

If you’re in the second group, chances are you’ve already looked beyond fiberglass or spray foam—so we’d like to introduce you to wood fiber insulation (if you haven’t already met). 

Wood fiber insulation has been a trusted material in Europe for more than two decades—used in everything from high-performance Passive House construction to historic retrofits. Now, for the first time, it’s being manufactured in the U.S. by TimberHP in Maine—bringing this proven material to North American builders and designers.

Since it’s newer on the scene in North America, let’s break down exactly what wood fiber insulation is: how it’s made, why it’s different, and why you should consider it for your next project.

A Smarter Use of Residual Wood Chips: How Wood Fiber Insulation Is Made

At its core, wood fiber insulation is exactly what it sounds like: insulation made from wood fibers. But it’s not just any wood. Lumberyards produce softwood chips during the process of milling round logs into square boards. These wood chips are then delivered to our refurbished paper mill in Madison, Maine, where the chips are refined and pressed into different insulation products:

• TimberBoard: a dense, rigid board for exterior continuous insulation
• TimberBatt: a semi-rigid batt for framed cavity applications
• TimberFill: a loose fill or dense pack for attics and walls

These products are manufactured using a clean, efficient, eco-friendly process, so wood fiber insulation products remain sustainable from the source. .

Proven Performance—Naturally

Wood fiber insulation isn’t just an environmentally responsible choice. It also offers a number of features that make it an exceptional solution for a range of building applications:

Effective Fire Resistance

Despite being made from wood, TimberHP insulation products are made to resist fire. TimberBatt and TimberFill both carry a Class A fire rating thanks to treatment with borate—a naturally occurring mineral that provides effective fire resistance without relying on harmful flame retardants. It offers powerful protection without the toxicity.

Superior Acoustic Comfort

TimberHP’s wood fiber insulation doesn’t just dampen sound—it outperforms in acoustic performance due to its high density and fibrous structure. Our insulation solutions often match or exceed mineral wool in common wall assemblies—and it all adds up to quieter, more comfortable indoor spaces, especially in multifamily and mixed-use buildings.

Year-Round Thermal Performance

Wood fiber has a superior heat storage capacity compared to conventional insulation; in addition to providing a stable R-value for reducing heating loads in winter, it also outperforms conventional insulation at keeping interiors cool in summer—ultimately improving year-round energy efficiency.

Vapor Open, Moisture Smart

TimberHP’s vapor-open profile helps avoid the moisture issues commonly associated with foam insulation products. Wood fiber allows water vapor to pass through rather than trapping it, helping prevent mold, condensation, and rot, and promoting improved indoor air quality and a longer-lasting building envelope.

Why You Haven’t Heard of Wood Fiber Insulation—Yet

Wood fiber insulation is a mainstay in Europe, where it has been used in high-performance and Passive House buildings for more than two decades. Strict energy efficiency standards and sustainability goals in countries like Germany, Austria, and Switzerland accelerated innovation and adoption of wood fiber materials long before the U.S. caught on.

So why now?

The U.S. is seeing a shift in the building design and construction industries. Architects, builders, and homeowners are demanding products that reduce carbon impact, improve occupant health, and deliver better performance over the life of the building. TimberHP’s wood fiber insulation checks every box—with the added bonuses of being sustainably sourced and manufactured in the U.S.

A Modern Material with Deep Roots

Wood fiber insulation is a smart, sustainable, and high-performing alternative to traditional insulation materials. It makes use of renewable forest resources that would otherwise go to waste, is manufactured with a clean process in a revitalized local facility, and offers a range of benefits that improve the comfort, durability, and health of indoor spaces. 

Those who specify, install, or sell wood fiber insulation can feel good about their impact on the built environment and the environment at large. If you hadn’t heard of wood fiber insulation, you have now, and this once-overlooked material is poised to change our thinking around and choices for insulation in North America. 

Curious how wood fiber insulation compares to what you’re currently using? Subscribe to our newsletter for regular updates about our wood fiber insulation products and to see how they stack up against fiberglass, foam, and mineral wool.