Deep Energy Retrofits with Hempcrete: Transforming Existing Buildings into High-Performance, Sustainable Spaces
As the global push for carbon neutrality intensifies, homeowners, architects, and contractors are turning to deep energy retrofits to dramatically reduce the energy consumption of existing buildings. One material is proving to be a standout solution in this movement: hempcrete.
In this blog, we’ll explore how deep energy retrofits with hempcrete can revolutionize your home or commercial property, reduce operational costs, increase comfort, and contribute to a low-carbon future.
What is a Deep Energy Retrofit?
A deep energy retrofit (DER) is a whole-building overhaul that goes far beyond conventional upgrades. While basic energy retrofits might include installing new windows or insulation, deep retrofits aim to slash energy use by 50% to 90% through comprehensive improvements to the thermal envelope, mechanical systems, air sealing, and material choices.
Key components of a deep energy retrofit include:
• High-performance insulation
• Thermal bridging elimination
• Air-tight construction
• Renewable energy systems
• Advanced ventilation (ERV or HRV systems)
• Sustainable, low-embodied carbon materials like hempcrete
Why Use Hempcrete for Deep Energy Retrofits?
Hempcrete is a bio-composite insulation material made from industrial hemp hurd, a lime-based binder, and water. It offers a game-changing blend of insulation, thermal mass, air quality control, and sustainability—all in one material.
Top Benefits of Hempcrete for Deep Energy Retrofits:
1. Superior Thermal Performance
Hempcrete has an R-value comparable to traditional insulation materials, but its true power lies in its thermal mass and vapor permeability. It stabilizes indoor temperatures by absorbing and slowly releasing heat, reducing HVAC loads and improving year-round energy efficiency.
2. Moisture Regulation & Mold Resistance
Unlike synthetic insulation, hempcrete ‘breathes’, preventing trapped moisture and mold growth. This makes it ideal for older homes that need a breathable wall assembly—especially those with solid masonry or stone construction.
3. Naturally resistant to fire, pests, and rodents
4. Carbon Sequestration
Hempcrete used in a retrofit can store atmospheric carbon, helping your project go beyond net-zero and into carbon-negative building territory.
You may be wondering, how much carbon can hempcrete sequester? Hempcrete sequesters roughly 110 kg (242 lbs.) of CO2 per cubic meter (35.3 ft.). That converts to 6.85 lbs. of CO2 sequestered per cubic foot of hempcrete. And for carbon sequestration per block, that’s about 4 lbs. of CO2 locked up in every 8x8x16 hempcrete block.
5. Acoustic Performance
Hempcrete walls provide excellent sound insulation, making retrofit projects not only energy-efficient but also quieter and more comfortable.
How to Retrofit with Hempcrete
1. Interior or Exterior Insulation
Hempcrete can be used to insulate:
• Interior walls (where exterior work isn’t feasible)
• Exterior façades (ideal for continuous insulation upgrades)
• Attics and floor systems
2. Wall Cavity Replacement
In historic buildings or homes with deteriorated insulation, removing old wall systems and replacing them with hempcrete infill ensures:
• Airtightness
• Breathability
• Deep insulation gains
3. Envelope Tightening
Sealing cracks, improving junctions, and integrating hempcrete (and lime plaster) around windows and doors reduces thermal bridging and air leakage—key factors in deep energy retrofits.
Case Study: Hempcrete in Historic Building Retrofits
Hempcrete is especially valuable in retrofitting historic or heritage buildings, where conventional materials fail to respect the original architecture or cause condensation issues. In contrast, hempcrete’s vapor-open properties protect the structure while enhancing energy performance.
Many homes from the 1800s to early 1900s—especially brick, stone, and timber buildings—benefit enormously from breathable hemp-lime wall insulation that doesn’t trap moisture.
A Retrofit for the Future
By choosing hempcrete for your deep energy retrofit, you’re not only making your building more energy-efficient, you’re investing in durability, health, indoor air quality, and the planet’s future.
Whether you’re a homeowner seeking better comfort, a developer targeting passive house standards, or a commercial property owner looking to reduce operating costs—Hemp and Block’s premium hempcrete blocks are a smart, scalable solution.
Ready to Retrofit Sustainably?
At Hemp and Block, we manufacture hempcrete building blocks engineered for deep energy retrofits and new construction alike. Our mission is to empower communities to build greener, smarter, and stronger—starting with each block.
Contact us today to get started on your deep energy retrofit project with hempcrete! Give us a call at 970-318-0479 or send a message through our contact form.
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