Aerogel is the perfect home insulation. R-value of R-10.3 per inch. It has very low thermal conductivity, low density, and high porosity. Most aerogel is manufactured from silica (sand)–the compound that makes up 59% of the earth’s crust–and air. Dead air spaces are the main insulator in most insulations. Aerogel products contain up to 99.8% air.
What is Aerogel?
Aerogel is a low-density solid gel. The liquid is removed and replaced with gas–usually air. Aerogel is also called “blue smoke”, “solid smoke”, and “frozen smoke” because of its appearance.
Most aerogel is made from silica which forms the solid part of the substance. Silica is a poor heat conductor. The air cannot move inside the substance–preventing both heat conduction and convection. Aerogel is only slightly heavier than air. One cubic meter weighs 1.5 kilograms. (35 cubic feet weighs 3.3 lbs.)
A flower resting on a piece of silica aerogel, which is suspended over a flame from a Bunsen burner. Aerogels have excellent insulating properties, and the flower is protected from the heat of the flame.
- 99.8% Air
- 39 times more insulating than the best fiberglass insulation
- 1,000 times less dense than glass
- Used on Mars Pathfinder’s rover
A quote from Dr. Peter Tsou of NASA’s Jet Propulsion Laboratory, “You could take a two or three bedroom house, insulate it with aerogel, and you could heat the house with a candle. But eventually the house would become too hot.”
How Aerogel Happened
Aerogel was created in 1931 as the result of a bet between Samuel Stephens Kistler and Charles Learned. Who could replace the liquid in a jelly jar with a gas and not reduce the volume? Kistler won the bet.
Freeze drying removes the liquid without causing the gel’s solid matrix to collapse. The first aerogels were made from a silica base. Kistler also used alumina, chromia, and tin oxide. In the late 1980s, manufacturers began to use carbon to manufacture aerogels. Other base materials used include iron oxide, copper, gold, and carbon.
Research and development departments have come up with multiple uses for aerogel Many of them before insulation products became viable.
Recent advances in reducing aerogel brittleness make aerogel a more versatile insulation product. Some of the products and uses include:
- Wall Insulation. Can be used independently or laminated to mineral wool or fiberboard to provide improved thermal resistance.
- Skylights. Sandwiched between two layers of Lexan for improved insulation.
- Windows. Sandwiched between two sheets of glass, it provides better insulation value than triple-glazed windows. The units are also much lighter.
- Tight Spaces. Can be packed into small and narrow cavities such as the space between window jambs and wall framing without losing any R-value.
- Pipe Wrap. Replaces fiberglass wrap. Takes up less space and provides better insulation value.
- Thermal Bridging. Installed as narrow thin strips on the inside face of wall studs and roof rafters, aerogel increases the overall R-value of the wall system.
- Drywall. Aerogel is added to drywall to increase exterior wall R-value.
- Plaster. Aerogel-based plaster increases insulation value. (Used when restoring historic buildings to add insulation while preserving the look.)
- Equipment Blankets. Prevent heat dissipation and provide soundproofing.
Other Aerogel Applications
Aerogel is used in many products–some of them seem a little strange. Here are a few.
- Tennis racquets.
- Clothing and blankets.
- Space suits and diving suits.
- Chemical spill absorption.
- Drug delivery.
- Aircraft de-icing.
- Thermonuclear warheads.
- Many others.
The benefits of aerogel as an insulation product include:
- Best Thermal Insulation.
- Sound Absorption.
- Water Permeable.
- Hydrophobic. High water-repellant characteristics. Reduces corrosion in high humidity and marine environments. At the same time, aerogel allows vapor to pass through it.
- Installation. Easy installation. Cuts with a utility knife. Can be removed and replaced without damage.
- Durability. Does not clump, sag, or crack. Has a longer service life.
- Saves Space. Uses less floor space than traditional insulation materials.
Aerogel may be the perfect insulation material but it does have a few problems. It is not a new invention but the insulation industry was slow to adopt it and figure out how to use it effectively. Commercial interest waned around 1970. Aerogel’s resurgence began in the 1980s with NASA’s use of the product and the expiry of some patents.
- Cost. About $2.30 per square foot for a 5 mm thickness.
- Availability. Aerogel is made in small batches–limiting mass distribution. It is not available from large building supply outlets.
- Brittleness. Does not hold up to tension.
- Respiratory. Potential for upper respiratory problems.
- PPE. Use Personal Protective Equipment including a respirator and gloves when handling aerogel.
All of these issues are being addressed by the manufacturers and improvements are announced regularly. Innovations like laminating aerogel onto insulation products such as mineral wool, plasterboard, and tiles are already available.
The European Union and Britain are standardizing aerogel guidelines. Population density and congested construction areas lead to more reliance on better insulating and soundproofing products.
Some of the top global aerogel manufacturers include:
- Aspen Aerogels
- Aerogel Technologies
- Svenska Aerogel Holding AB
- Green Earth Aerogel Technologies
- Cabot Corporation