From Waste to Warmth: Using Recycled Clothing as Home Insulation

Over 100 billion items of clothing are produced annually worldwide, and use large amounts of water, chemicals, and energy. Approximately 92 million tonnes of clothing waste are created each year. Used clothing is often shipped overseas where it is burned, or can end up in local landfills where it can take up to 200 years to decompose.

At the same time, insulation is something every building needs, but manufacturing it requires energy, chemicals, and raw materials.

I wanted to find out whether these two problems could solve each other. My hypothesis was that recycled materials could provide thermal insulation in the same way as R-14 insulation. I found out that shredded clothing actually outperforms regular insulation.

Creative solutions to everyday waste can have a big impact. This project is my way of proving that something that people throw away might be what we need to build a more sustainable world.

Design of Experiment

A heat loss experiment was done using a wooden test box with wall sections fitted with vapour barrier and designed to allow different insulation materials to fill the sections. Temperature data were collected using calibrated thermocouples (K-type, ±1.1°C accuracy) positioned at six locations: inside the box (2 sensors), on the exterior wall surface (2 sensors), in the heat source, and in the room. A data logging system recorded temperature measurements throughout each trial.

Phase 1 tested whether any recycled materials could outperform regular home insulation.

Phase 2 tested whether shredded clothing could outperform regular clothing as insulation.

Thermocouple Calibration

Before testing, thermocouples were calibrated using ice baths (0°C) and boiling water baths (100°C).

Materials Tested

In Phase 1, six insulation types were tested:

No insulation (control)

R-14 fiberglass insulation (regular home insulation)

Clothing

Cardboard

Plastic recycling

Grocery bags

In Phase 2, 3 trials of each of R-14, regular clothing, and shredded clothing insulation were done.

Experiment

For each trial:

(1) walls were filled with a single insulation material to the same height,

(2) exactly 2 liters of water were heated to boiling (100°C),

(3) the heat source was sealed inside the box with an insulated lid,

(4) temperature data for each thermocouple (every 30s in Phase 1 and every 1m in Phase 2) were recorded for approximately 20-25 hours as the system cooled naturally.

Control Variables

Box dimensions were held constant, heat source volume was set at 2L, initial water temperature was 100°C for all trials, room location remained unchanged, and data logging interval was fixed.

Sources of Error

Challenges including room temperature fluctuations, humidity from boiling water, and movement of thermocouples, introduced some error. Over 50,000 data points were collected in Phase 1 and Phase 2 to find trends.

Phase 1: Proof of Concept

In Phase 1 of the experiment, more than 50,000 temperature measurements were collected, which showed that recycled materials can be used as regular home insulation, and that clothing can insulate as well or better than regular R-14 home insulation.

Heat retention was quantified by measuring the time for a heat source to cool from 80°C to 30°C. Clothing retained heat 22 minutes longer than R-14 insulation, which is a 2.4% improvement (Figure 1).

Exterior walls are where interior heat meets outdoor cold. When the heat source was at its peak (80–100°C), outside wall temperatures revealed differences in the effectiveness of different insulations. Clothing limited exterior wall heating to approximately 4°C above baseline, outperforming all other tested materials (Figures 2 and 3).

The average interior wall temperature during the cooling phase (hours 1–15) showed that clothing also kept the highest interior wall temperature (Figure 4).

The R-value for clothing is therefore greater than R-14.

The overall ranking of materials tested was:

(1) Clothing

(2) R-14 insulation

(3) Grocery bags

(4) Cardboard

(5) Plastic recycling

(6) No insulation

Phase 2: Processing the Clothing

At the Ottawa Regional Science Fair, many judges asked whether shredding the clothing would change heat retention.

Phase 2 of the experiment tested whether shredding of clothing materials increases thermal retention.

3 trials of each of R-14 insulation, clothing, and shredded clothing were done, so that the results were reproduced and a statistical test with the data, the t-test, could be done to find out if the differences between the insulations were real.

In these trials only the inside wall probe temperatures (2 in total) were recorded because these probes were measuring the ability of the material to keep the heat inside the walls.

The walls were filled with R-14 insulation, clothing, and shredded clothing in each trial. The walls were filled with approximately 10% less shredded clothing by weight than clothing because the volume of the clothing was increased by shredding it.

Heat retention was quantified by measuring the time for a heat source to cool from 45°C to 25°C (Figure 5). The graphs show the average temperature vs. time across the 3 trials. The standard deviations were 1-2% on each data point.

It is clear from the graphs that over time, and around typical house temperatures, the ranking was:

(1) Shredded clothing

(2) Clothing

(3) R-14 insulation

A t-test showed that clothing was significantly better than insulation, and shredded clothing was better than both clothing and insulation. The p value was low for all cases so it is a meaningful difference statistically (Figure 6).

The R-value of shredded clothing is higher than the R-value of whole clothing.

The results show that recycled clothing can provide thermal insulation that is equal to or better than commercial R-14 insulation.

Increasing the material surface area by shredding the clothing increases performance as insulation, which means that less clothing can be used to achieve the same insulation effect.

These results could impact:

Landfills: 92 million tonnes of clothing waste is created every year. If some of this waste can be used for building construction, it would reduce the amount that ends up in landfills.

Energy Consumption: Manufacturing regular home insulations uses a lot of energy. Using recycled clothing as insulation could remove some manufacturing steps and avoid carbon emissions.

Use of Chemicals: Binding chemicals are needed to make bats of insulation. The recycled clothing performed well without the need for binding chemicals to be released into the environment.

How We See Waste: The results help people see value in something that was previously seen as waste and encourages people to think creatively about recycling.

Further research will explore how recycled clothing insulation performs over time, in humid conditions, or as a fire hazard compared to regular home insulations. If these questions can be answered, recycled clothing insulation could become an option for builders and homeowners looking to reduce on cost and their environmental footprint.

Vision:

Transform clothing waste into insulation for buildings to give old clothes a second life as building materials, instead of ending up in landfills.

Further Research:

Investigate the best shredding size and packing methods.

Build a large test structure to test performance in realistic dimensions.

Meeting Safety Standards:

Test fire-retardant treatments to comply with building codes.

Test durability for settling, moisture absorption, and pest resistance.

Practical Analysis:

Conduct cost analysis: purchasing used clothing and shredding equipment, and the cost of installation over regular home insulation.

Conduct trials in actual homes.

I would like to give special thanks to the people without whom this project would not have been possible.

First, to my family: My granddad, Bob Burk from Carleton University, generously lended me thermocouples from his lab. My dad, Tyler Dumouchel, helped me build the test box for the experiment and supported me in learning how to use the data collection software and statistics. My mom, Ashley Burk, and my brother, Gray Dumouchel, gave me encouragement, graphic design help, and spent hours shredding clothing.

Thank you also to my school. Ms. Angela Thompson and the science department at Turnbull School provided guidance and encouragement throughout this project.

I am grateful for all your help.

Books:

Walpole, R. E. et al. (2002). Probability & Statistics for Engineers & Scientists, Seventh Edition. Prentice Hall. (p. 219, t-Distribution).

Tipler, P.A. (1999). Physics for Scientists and Engineers, Fourth Edition, Volume 1. W.H. Freeman and Company. (p.581, Heat capacity).

Journal articles:

Patti, A. et al. (2021). Circular Economy and Sustainability of the Clothing and Textile Industry. PMC/National Institutes of Health. https://pmc.ncbi.nlm.nih.gov/articles/PMC8257395/

Web pages:

Allplan. (2018). Sustainable building: Recycled insulation materials. https://www.allplan.com/blog/recycled-insulation-materials/

Ball, M. (2025). Environmental impact of home insulation. https://www.ecodampsolutions.com/blog/the-environmental-impact-of-different-home-insulation-methods/

BNP Media. (2018). Moisture and insulation. https://www.buildingenclosureonline.com/articles/87569-what-you-need-to-know-about-moisture-and-insulation

Customcy. (2026). Global Clothing Production Statistics - Report 2026. https://customcy.com/blog/apparel-industry-statistics/

Department of Energy. (2022). Insulation. https://www.energy.gov/energysaver/insulation

Fireresist. (2025). Fire proofing insulation. https://fireresist.co.uk/guide-to-fire-proofing-insulation-for-building-safety/

Green Insulation Group. (2023). Recycled insulation and carbon footprint. https://greeninsulationgroup.com/using-recycled-insulation-can-reduce-your-carbon-footprint/

Institute of Physics. (n.d.). Conduction, convection, and radiation. https://spark.iop.org/conduction-convection-and-radiation

Natural Insulation. (2013). Environmental impact of home insulation. https://www.naturalinsulation.co.nz/home-insulation-info/home-insulation-environmental-impact/

Natural Resources Canada, Office of Energy Efficiency. (2020). Energy Use in Canada: Trends Publications. https://oee.nrcan.gc.ca/publications/statistics/trends/2020/residential.cfm

PennState College. (2026). Heat loss and transfer. https://courses.ems.psu.edu/egee102/node/2053

UniformMarket. (2025). Global Apparel Industry Statistics (2025). https://www.uniformmarket.com/statistics/global-apparel-industry-statistics

US Department of Energy. (2023). Insulation materials. https://www.energy.gov/energysaver/insulation-materials