Building or renovating a tiny home? One of the most important decisions you’ll make is choosing the right insulation. Insulation is crucial for maintaining a comfortable temperature and lowering energy bills. For eco-friendly tiny home dwellers, it’s also important to select insulation with a minimal environmental impact. Here are six of the best green insulation options to consider for your tiny house.
1. Recycled Cotton Insulation
Cotton insulation is made from recycled cotton scraps, such as old clothes, fabrics, and blue jeans. The cotton fibers are treated with borate salts for fire and pest resistance. This eco-friendly insulation has many advantages:
Safe and Sustainable Materials
The main ingredient, recycled cotton, is a rapidly renewable and abundant resource. Cotton insulation diverts waste from landfills and reduces demand for new cotton production. The borate treatment is non-toxic to humans.
Excellent Acoustics
The dense cotton fibers deaden sound significantly better than fiberglass. Cotton insulation helps block outdoor noise and absorbs sound between rooms.
High R-Value
Cotton insulation delivers an R-Value of 3.7 per inch. At standard wall thickness, it provides great insulation from heat and cold. The densely packed cotton fibers have low convective flow.
Moisture Control
Cotton insulation absorbs and releases moisture slowly. This helps maintain comfortable humidity levels and avoid condensation issues.
Non-Itchy Application
Installers can work safely with cotton insulation without scratchy fibers or chemical irritants. The insulation is also suitable for exposed applications like cathedral ceilings.
Look for cotton insulation certified by UL Environment to ensure the materials and manufacturing meet green standards. Top brands to consider include UltraTouch and Bonded Logic.
2. Mineral Wool Insulation
Mineral wool refers to fiber insulation made from natural stone or recycled slag from steel production. It’s an eco-friendly option because:
High Recycled Content
Many mineral wool products contain a high percentage of recycled slag content. Rock wool specifically uses natural stone waste.
Green Certifications
Look for mineral wool certified by UL Environment to ensure sustainable sourcing and manufacturing.
Excellent Thermal Performance
Mineral wool delivers an R-Value of 3-4 per inch. It resists heat flow while allowing water vapor diffusion.
Fire Resistance
Mineral fibers withstand temperatures above 1000°F before melting. The material is non-combustible and adds fire protection.
Long-term Stability
Mineral wool maintains its R-Value and integrity over time. There are no binders to break down or chemicals to off-gas.
Leading brands of mineral wool include Roxul ComfortBoard and Thermafiber. Opt for unfaced boards to avoid added adhesives.
3. Cellulose Insulation
Cellulose insulation provides an eco-friendly option made mainly from recycled paper products. Benefits include:
High Recycled Content
Cellulose contains around 85% recycled paper fiber, predominantly post-consumer waste. Some has 100% recycled content.
Decent R-Value
Typical R-Values range from 3.2-3.8 per inch. Dense packing adds more thermal resistance.
Good Fire Resistance
Cellulose won’t burn or melt. It’s treated with natural borate compounds to resist fire.
Moisture Control
The recycled paper fibers readily absorb and release moisture, helping regulate humidity.
Low Dust Installation
Cellulose application has minimal dust due to the dense packing. Fiber particles are too large to be inhaled.
Opt for third-party green certification from brands like GreenGuard or UL GREENGUARD. Top cellulose options include Densepack, Kraft Faced, and AllBorate.
4. Hemp Insulation
Hemp insulation offers a rapidly renewable and sustainable insulation choice. Key eco-friendly benefits include:
Fast Growing Plants
Hemp plants can be harvested just four months after planting, allowing rapid replenishment. Their fibrous stalks require minimal resources to grow.
Carbon Negative Material
Hemp actively absorbs CO2 as it grows. Products like hempcrete can sequester carbon.
Decent Thermal Performance
Hemp insulation typically provides an R-Value around 2.5 per inch. It must be installed thicker than other insulations.
Moisture Control
The absorbent hemp fibers help maintain indoor humidity levels and reduce condensation risk.
Safe Bio-based Material
Hemp insulation contains no chemical irritants or toxic binders. It’s naturally pest and fire resistant.
Look for hemp insulation products certified by organizations like Control Union Certifications and USDA BioPreferred. Leading brands include Hempcrete, Naturefiber, and HempWool.
5. Straw Bale Insulation
For a biodegradable insulation with very low embodied energy, straw bale insulation is an excellent eco-friendly choice. Benefits include:
Ultra Low Impact Material
Using leftover straw waste to insulate walls avoids significant resource use and carbon emissions.
High R-Value
At around R-3 per inch, straw bale walls provide substantial thermal resistance when packed tightly.
Natural Pest Resistance
The dry, dense straw deters pests from burrowing without chemicals. A lime plaster coating adds protection.
Excellent Fire Resistance
Packed straw can withstand intense heat and is naturally fire resistant. Non-toxic borates can be added too.
Easy Installation
Straw bales can be stacked like bricks and anchored for straightforward installation. Plaster coatings keep out air.
When sourcing straw bales, look for local farmers using sustainable practices. Handling precautions are needed to avoid potential straw dust allergies.
6. Advanced Closed-Cell Spray Foam
While regular spray foam has significant downsides, advanced third-party certified closed-cell spray foam improves upon sustainability and indoor air quality:
Higher Eco-Friendly Content
Some closed-cell options have 5-10% recycled plastic content, renewable soy oils, and non-toxic propellants.
Safer Application Process
Low/no VOC options use safer spray chemicals and additives to limit installer and occupant exposure.
Prevent Energy Loss
The superior air sealing ability of closed-cell foam maximizes energy efficiency. No gaps or leaks for air infiltration.
Excellent Noise Reduction
Closed-cell foam dampens sound transmission extremely effectively for its thickness.
Durable Water Resistor
Closed cells make the foam waterproof. No absorption or structural damage issues.
Check certification from UL GREENGUARD, EcoLogo, or Green Seal when selecting closed-cell spray foam. Top eco-friendly spray foam brands include Icynene ProSeal and Lapolla Spray Foam.
Questions to Consider When Selecting Tiny Home Insulation
Here are some key factors to weigh when evaluating insulation options for your tiny house build:
Is it comfortable to install?
Consider safety equipment needed and potential skin irritation or particle inhalation.
How eco-friendly are the materials sourced?
Look for recycled, rapidly renewable, or waste content. Check certifications.
Does it control moisture and condensation well?
Preventing excess humidity or mold growth is crucial in compact spaces.
Will installation achieve consistent coverage and density?
Any gaps or voids severely lower insulation effectiveness.
Does it contain binders, formaldehyde, or VOCs?
Avoid chemical additives that can pollute indoor air quality.
Is it too flammable for safe use?
Some insulation contains plastic films or oils that are fire hazards.
Does the R-value achieve your thermal needs?
Calculate minimum R-values for your climate’s temperature extremes.
Can it get wet if plumbing leaks occur?
Some insulation types lose all insulating value and promote rot when wet.
Is it prone to settling and reductions in R-value over time?
Dense, stable insulation maintains insulation performance long-term.
Are rodents or insects attracted to the insulation?
Some natural fiber options require protection from nesting pests.
Key Considerations When Installing Tiny Home Insulation
Proper installation is crucial to achieve the full insulating potential. Here are key factors to keep in mind:
Choose the Right Insulation Thickness
Calculate minimum R-values needed for floors, walls, and ceilings based on your climate.
Prioritize Consistent Coverage
Completely fill voids to prevent air pockets or gaps that reduce effectiveness.
Avoid Compression or Movement
Installation should lock insulation into place so it stays dense over time.
Protect Insulation from Moisture
Prevent groundwater, rain leakage, and condensation from compromising insulation.
Install Vapor Barriers Correctly
Pay close attention to proper vapor barrier placement to avoid moisture issues.
Seal Air Leaks Thoroughly
Use caulk, foam, and weather stripping to prevent costly air infiltration.
Vent Properly
Ensure bathroom, kitchen, appliance and roof venting to avoid moisture buildup.
Use Pest Prevention Measures
Add wire mesh, metal flashing, or borate sprays if needed.
Consider a Radiant Barrier
Adding a reflective layer boosts insulation performance. Useful in hot climates.
Typical Tiny House Insulation R-Values to Target
Here are typical R-value recommendations for different elements of a tiny home:
Floor: R-13 to R-22
Foam panels or rigid fiber insulation Works well.
Walls: R-15 to R-21
Fiber, foam board, or blown-in insulation.
Ceilings: R-30 to R-40
Maximize loft insulation since heat rises.
Windows: R-3 to R-5
Choose double-paned windows. Storm windows add more R-value.
Doors: R-5 to R-9+
Use insulated doors or separately insulate doors.
Actual R-values will depend on your climate and the tiny house design. The higher the R-value, the better the thermal performance.
Frequently Asked Questions About Tiny Home Insulation
Here are answers to some common questions about insulating a tiny house:
What areas of my tiny home most need insulation?
Focus on the building envelope – walls, floors, ceilings, and any hatch or door access. Windows and skylights also impact heat gain/loss.
Does insulation need an air gap to work properly?
No, insulation does not require an air gap. In fact, avoiding gaps improves performance.
Should I use faced or unfaced insulation?
In most cases, unfaced insulation without attached vapor barriers is preferable. It allows interior and exterior vapor control layers.
How do I calculate how much insulation I need?
Add up the surface area for walls, ceilings, floors. Multiply by the target R-value per square foot based on your climate.
Does insulation reduce noise?
Yes, in addition to thermal insulation, materials like mineral wool and spray foam also dampen noise transmission.
How often should insulation be replaced?
If properly installed and undamaged, insulation should last the lifetime of the house without replacement needed.
Can you use natural insulation in rainscreen walls?
Yes, you can incorporate exterior continuous insulation in a rainscreen wall assembly while protecting it from moisture.
Does insulation need to go in interior wall cavities?
It’s recommended to maintain thermal envelope continuity by insulating any interior cavities against unconditioned spaces.
Can too much insulation cause problems?
Excess insulation can potentially cause moisture issues if vapor barriers aren’t properly integrated. Balance insulation levels based on your climate.
Conclusion
Insulation is a key component of an eco-friendly and energy efficient tiny home. When selecting insulation, consider recycled/natural materials, high R-values per inch, air sealing ability, fire resistance, moisture control, and ease of installation. By choosing the right green insulation and installing properly, you can keep your tiny house comfortable in any weather while minimizing environmental impact.