Will nanotech reduce the spread of viruses and bacteria?

Every year, millions of people catch the flu resulting in 31.4 million doctor visits costing billions in lost productivity and healthcare expenses. A 2016 study pegged productivity losses at a $5.8 billion hit to American business. With the deadly Covid-19 pandemic, the blow to small, medium and large businesses and taxpayers is staggering. Worse yet, tens of thousands of people die from exposure to the latest strain of antibiotic-resistant germs and viruses like influenza, MRSA, Norovirus, SARS and now the deadly Coronavirus. So, how can we mitigate the spread of viruses and other pathogens as well as prevent the next pandemic?

By now, most people on the planet are aware that the Sars-CoV-2 virus causing the Covid-19 pandemic can be transmitted via droplets from sneezing, coughing or direct transfer. But various peer-reviewed studies and lab reports also show that it can live on common surfaces for hours and days. Thus, it’s important to keep those surfaces clean. But, that’s not easy. For decades, the main defense against germs and viruses has been spraying and pouring billions of gallons of harsh and toxic cleaning agents over everyday surfaces in hopes of keeping them “clean”.  Sadly, all this effort is temporary. The next cough or sneeze or touch can put those germs back. Testing proves those surfaces are just as dirty soon after, requiring even more chemicals and protective measures. Our global reliance on antibiotics and billion dollar drugs is proof that cleaning (or cleaning methods) are largely ineffective. Worse yet, all those cleaning chemicals get into our food, our pets and the environment causing cancer and all sorts of unnecessary health risks and damage. Which requires even more drugs! What if there was a better way to make all those surfaces somehow just stay clean.

With new nano-technology, that day may be here. Check out these two novel approaches:

Anti-microbial Materials

Microban is a company that sells anti-microbial compounds to other manufacturers so they can be “baked into” manufactured products like food storage, yoga mats and hospital bed rails. The anti-microbial products then release trace amounts of silver or other deadly agents to fight off or disable the attacking pathogen. This mitigates or reduces the need for constant cleaning to fend off the germs typical to those applications. The downside is the anti-microbials that are baked in don’t necessarily protect against a broad spectrum or the latest viral strain. The other downside is all the other surfaces that are NOT protected. Do you know which, if any, building materials in your home or office have anti-microbial properties? Probably not. The process of saturating Microban’s proprietary chemicals into product manufacturing can be very expensive. With consumers and supply chains always looking for lower costs, it should be pretty logical that most consumer goods and building materials are NOT anti-microbial. And without testing, how do you really know if all your surfaces are protected anyway? That’s where PermaClean shines.


PermaClean is similar to Microban except they take a more elegant approach. PermaClean’s food-safe, nano-coatings are applied to the surface of common materials causing them to be highly water and oil repellent. Here’s where it gets interesting. In the molecular world, size matters. Think of these nano-coatings as a super-fine mesh of molecules bonding together so small that they easily block oil and water molecules. Since bacteria and viruses are 100 – 1,000 times larger than water molecules, they are easily blocked as well. That means nasty stuff like salmonella, MRSA and SARS viruses (e.g. coronavirus) won’t stick to those surfaces anymore! The submicroscopic barrier gives that material new super powers to repel water, oils, bacteria, germs, mold, mildew and of course, viruses. PermaClean’s nano-coatings work on virtually any substrate (material), including: plastic, metals, glass, textiles, stone, concrete and others.

By making those everyday surfaces super hydrophobic, oleophobic and resistant to pathogens, the need for frequent chemical cleaning is greatly reduced. Everyday surfaces stay cleaner longer and become significantly more resistant to soiling, mold, mildew, bacteria and other bad stuff. Based on our testing, simple and frequent wipe downs are more effective. In fact, water may even be the only “cleaning agent” needed. That’s a game-changer in the environmental sustainability world. For health care, that could be a big, big edge against pandemics. Perhaps the best part is the cost savings. Longer lasting clean means better health safety, lower health care costs, less time cleaning, reduced environmental impact and lower overall costs to operate your business or home.

Let’s see how this can impact the following industries immediately.

Food Service.

Salmonella seems to be omnipresent in our lives since it is naturally existing in all poultry like chicken, eggs and other everyday foods. Undercooked poultry will make you very sick. But so will unwittingly spreading of those germs during food prep. Check out this video (below) to see what happens when a common food prep surface, like stainless steel, is PermaCleaned. Spolier alert, the results are shocking.

PermaClean coatings form a tight barrier so bacteria and other pathogens can be washed away with water.

Can you think of any fast casual or quick serve restaurant brands whose stock price would have greatly benefited be being PermaCleaned?

Schools and Public Spaces.

Social distancing and constant hand washing are helpful, but pretty impractical and unreliable. Ask any teacher or parent. Kids are little “germ factories”. Why? First, little kids are just developing sanitary practices like proper hand washing and covering up when sneezing. Heck, I’d say most adults are still “learning”. Anyway, since babies and kids are also learning by tactile feel, they tend to touch and even taste all kinds of gross things. Then, those little darlings inadvertently pass those germs along to everyone else before any symptoms even show up. Homeless people have similar issues. They are constantly exposed to the elements and live in highly unsanitary conditions with sparse public facilities available for personal hygiene. Those facilities require even more rigorous cleaning that is costly and rarely accomplished. Since humans are so contagious before symptoms are revealed, that’s precisely why the flu and other deadly viruses like the Coronavirus are so scary. They are transmitted by sneezing and coughing which can turn into a global emergency overnight. Protecting employees and the public takes diligence and efficient means. Without that, people die and entire economies can lay in ruins, fast. Look at the Covid-19 pandemic. Can you think of any teachers, school districts, colleges or civic spaces that would benefit by being PermaCleaned?

Airplanes, Theaters, churches and other gathering places.

Imagine sitting down in a comfy chair, ready to enjoy the music or flight, then you realize there’s a big patch of goo on the back of your chair. Hopefully that doesn’t happen, but what if someone before you sneezed into their hand and touched your seat back, leaving a nice petri dish of germs or bacteria waiting for you to sit on or lean against. If those seats were made of Microban-impregnated materials or were coated by PermaClean technicians you’d be better protected from undue exposure. If it’s your business, your guests would have peace of mind so you can focus on your core business instead of wondering if your venue would be the epicenter of the next pandemic. Can you think of any airlines whose flight attendants would be so relieved to have seats and interiors PermaCleaned?

Office spaces.

Can PermaCleaned offices protect workers?

In business, productivity is everything. In fact, productivity is a bell weather of the American economy. When your business depends on people to get things done, which is pretty much every business, you need them healthy. So, if staff and visitors are worried about cleanliness or out sick, they will be a lot less productive. PermaCleaning common touch areas will help keep everyone safer and you guessed it, more productive. Can you think of any property management companies that would attract more customers if all their properties were PermaCleaned?



Methicillin-resistant Staphylococcus aureus (MRSA)

Easily transmitted in a hospital environment and resistant to most staphylococcus antibiotics including oxacillin, penicillin, amoxicillin, and methicillin, MRSA has only a few expensive treatment options, and there are challenging side effects. From 1999 to 2005 the estimated number of MRSA related hospitalizations more than doubled, from 127,036 to 278,203 causing a national priority for disease control. In 2010 encouraging results from the Center for Disease Control indicates a 28% decrease in invasive (life-threatening) MRSA infections in a hospital setting. The estimated cost of MRSA treatment in 2005 was $3.2 billion to $4.2 billion nationwide.(1)

Staphylococcus aureus – S. aureus can cause a range of illnesses, from minor skin infections such as pimples, impetigo, boils (furuncles), cellulitis folliculitis, carbuncles, scalded skin syndrome and abscesses to life-threatening diseases such as pneumonia, meningitis, osteomyelitis, endocarditis, toxic shock syndrome (TSS), bacteremia and sepsis. The systems it affects range from skin, soft tissue, respiratory, bone, joint, endovascular to wound infections. It is still one of the five most common causes of nosocomial infections and is often the cause of post-surgical wound infections. Each year, some 500,000 patients in American hospitals contract a staphylococcal infection.

Clostridium difficile (C. diff) – C. diff is a bacterium that can cause symptoms ranging from diarrhea to life-threatening inflammation of the colon. C. diff most commonly affects older adults in hospitals or long term care facilities. In recent years, C. diff infections have become more frequent, more severe and more difficult to treat. While MRSA infection rates are decreasing in response to stepped-up prevention efforts within hospitals, diseases caused by C. diff have increased each year since 2007. [Mayo Clinic Staff, 2010].

Listeria monocytogenes – Listeriosis is a serious infection usually caused by consuming food contaminated with Listeria monocytogenes. It causes significant public health risks responsible for approximately 1,600 cases annually. Before 2011, the largest outbreak occurred in 2002, when 54 illnesses, eight deaths, and three fetal deaths in nine states were associated with consumption of contaminated turkey deli meat. The 2011 outbreak, caused by tainted cantaloupe, infected a total of 139 persons with any of the four outbreak-associated strains of Listeria monocytogenes. The outbreak spread over 28 states and resulted in 29 deaths.(4)

Escherichia coli – E. coli consists of a large and diverse group of bacteria. Although most strains are harmless, other strains of E. coli can cause illnesses such as diarrhea, urinary tract infections, respiratory, and pneumonia. In most cases of disease-causing outbreaks, Shiga toxins produced by E. coli are responsible. Recent multistate foodborne outbreaks include Lebanon Bologna 2011, Hazelnuts 2011, Shredded Romaine Lettuce 2010, and Beef 2010, resulting in massive product recalls.(5)

Group A Streptococci (GAS) – GAS is a bacterium often found in the throat and on the skin. People may carry Group A Streptococci and have no symptoms of illness. Most GAS infections are relatively mild illnesses such as “strep throat,” or impetigo. Occasionally these bacteria can cause severe and even life-threatening diseases when bacteria get into parts of the body where they are not usually found, such as the blood, muscle, or the lungs. These infections are termed “invasive GAS disease.” About 9,000-11,500 cases of invasive GAS disease occur each year in the United States, resulting in 1,000-1,800 deaths annually.(7)

Pseudomonas aeruginosa – P. aeruginosa is an increasingly prevalent opportunistic human pathogen and the most common gram-negative bacterium in nosocomial infections. P. aeruginosa is responsible for 16% of nosocomial pneumonia cases, 12% of nosocomial urinary tract infections, 8% of surgical wound infections, and 10% of bloodstream infections.(8)

Streptococcus pneumonia – S. pneumonia typically enters the lung when airborne droplets are inhaled, but can enter through the bloodstream when there is an infection in another part of the body. There were 50,774 deaths in the US in 2009 attributed to pneumonia. It is estimated that up to 2.3% of all nursing home patients have pneumonia at any given time.(8)

Bacillus anthracis – Anthrax is an acute disease caused by Bacillus anthracis. Most forms of the disease are lethal, and it affects both humans and other animals. Anthrax spores can be produced in vitro and used as a biological weapon. Spores of B. anthracis spread anthrax. Clothing or shoes can transport these spores. The body of an animal that had active Anthrax at the time of death can be a source of Anthrax spores. A lethal infection is reported to result from inhalation of about 10,000 – 20,000 spores, though this dose varies among host species. Testing at the University of Cincinnati by Dr. Grinshpun used Bacillus subtilis as a surrogate.


Norwalk Virus –This virus is a Norovirus. Noroviridae is a group of related, single-stranded RNA, highly contagious infections and the most common cause of acute gastroenteritis in the United States. Known by other names such as stomach flu and food poisoning, it is responsible for 50% of food-borne outbreaks of gastroenteritis. Noroviruses spread from person to person by direct contact, touching contaminated surfaces, and contaminated food and water supplies.(12)

H1N1 Virus (Swine Influenza) – The H1N1 virus is a unique strain of influenza. The Centers for Disease Control determined that the pressure contained genes from four different flu viruses – North American swine influenza, North American avian influenza, human influenza, and swine influenza viruses typically found in Asia and Europe. The virus spreads from person to person by droplets from coughing and sneezing and by touching a person contaminated with the virus, then rubbing one’s eyes, nose or mouth.(14)

H5N1 Virus Avian Influenza (Bird Flu) – H5N1 has evolved into a flu virus strain that infects more species than any previously known strain, is deadlier than any formerly known strain, and continues to grow, becoming both more widespread and more deadly. Epidemiologists are afraid the next time such a virus mutates; it could pass from human to human. Direct transmission of avian viruses to humans is possible. Testing of photocatalysis on H5N1 was completed at Kansas State University using H5N8 as a surrogate.(15)


Stachybotrys chartarum – S. chartarum is a black mold that produces its conidia in slime heads and is found in soil and grain as well as cellulose-rich building materials and damp or water-damaged buildings. It requires high moisture content to grow and is associated with wet gypsum material and wallpaper. Health problems related to this mold have been documented in humans and animals since the 1930s and more recently linked with “sick building syndrome.”(16)

Candida albicans – C. albicans is a diploid fungus that grows as both yeast and filamentous cells and a causal agent of opportunistic oral and genital infections in humans. Systemic fungal infections (fungemias) including those by C. albicans have emerged as important causes of morbidity and mortality in immune-compromised patients (e.g., AIDS, cancer chemotherapy, organ or bone marrow transplantation). C. albicans biofilms may form on the surface of implantable medical devices. Besides, nosocomial infections by C. albicans have become a cause of significant health concerns.(17)


3fficient is dedicated to cost savings and sustainable carbon reduction for our clients. PCO units from 3fficient use low voltage technology to power our devices so they can be powered over ethernet or low voltage building sources. Our coatings and PCOs last orders of magnitude longer than their industry alternatives like chemical cleaning and air filters so maintenance costs are reduced or eliminated in some cases. They are even packed with recycled materials. Preference is shown to suppliers that share these values.

Stay tuned for more videos and other helpful solutions as they become viable.


(1) Center for Disease Control and Prevention MRSA statistics retrieved Nov. 6, 2011 from http://www.cdc.gov/mrsa/statistics/index.html

(4) Center for Disease Control and Prevention Listeria Statistics, http://www.cdc.gov/listeria/statistics.html

(5) Center for Disease Control and Prevention Multi-State Foodborne Outbreaks. http://www.cdc.gov/outbreaknet/outbreaks.html#ecoli

(6) Environmental Science and Technology, vol. 32, no. 17, pp. 2650-2653, 1998 – Mineralization of bacterial cell mass on photocatalytic surface in air, Jacoby, W.A., et al, The National Renewable Energy
Laboratory, Golden, Colorado 80401-3393, and Department of Chemical Engineering, University of Missouri-Columbia, Columbia, Missouri 65211

(7) Center for Disease Control and Prevention Group A streptococcal (GAS) Disease, http://www.cdc.gov/ncidod/dbmd/diseaseinfo/groupastreptococcalg.htm

(8) Van Delden, C C, Iglewski, BH. Cell-to-Cell Signaling and Pseudomonas aeruginosa Infections. Retrieved Nov 18, 2011 from http://wwwnc.cdc.gov/eid/article/4/4/98-0405.htm

(9) Center for Disease Control and Prevention Pneumonia. http://www.cdc.gov/nchs/fastats/pneumonia.htm

(10) Control of Aerosol Contaminants in Indoor Air: Combining the Particle Concentration Reduction with Microbial Inactivation, Grinshpun, Sergey et al; Department of Environmental Health, University of Cincinnati, 2332 Eden Avenue, PO Box 670056, Cincinnati, OH 45267-0056

(12) Surveillance of Norovirus Outbreaks Retrieved November 22, 2011 from http://www.cdc.gov/features/dsNorovirus/

(13) Evaluation of the Efficacy of Ecoquest’s Decontamination Systems in Reducing Murine Norovirus Titers Performed by Dr. Lela Riley, RADIL LLC, Columbia, MO Nov 18,2008

(14) Center for Disease Control and Prevention Influenza. http://www.cdc.gov/h1n1flu/

(15) Avian Influenza A (H5N1) Infection in Humans by The Writing Committee of the World Health Organization (WHO) Consultation of Human Influenza A/H5 in the Sept. 29, 2005 New England Journal of Medicine

(16) Nelson, D. “Stachybotrys chartarum: the toxic indoor mold”. APSnet. American Phytological Society. Archived from the original on 28 August 2005. http://web.archive.org/web/20050828033934/http://www.apsnet.org/online/feature/stachybotrys/. Retrieved 19 September 2005.

(17) Ryan KJ, Ray CG (editors) (2004). Sherris Medical Microbiology (4th ed.). McGraw Hill. ISBN 0-8385-8529-9.

(18) ASHRAE Transactions, Volume III, Part 2Evaluation of Photocatalysis for Gas-Phase Air Cleaning – Part 1: Process, Technical and Sizing Considerations, Dean T. Tompkins, et al.

How does a lotus leaf protect your car?

Something everyone on the planet has first hand experience with is cars.  With harsh weather, sunshine, road salts and other chemicals being thrown at your vehicle, literally at breakneck speeds, protecting the paint and underlying metal is a big challenge.  Once the clear coat or paint starts eroding, your expensive vehicle starts looking bad.  Or worse, the metal starts corroding…  So how does a lotus leaf protect the paint?  Is it some new kind of vegan wrap?  No, not exactly.

The surface of a lotus leaf actually repels water.  It’s how the giant leaf stays afloat and shields the fish underneath from the sun and other predators. By studying and learning from nature, biologists and chemists have been able develop amazing new nano-coatings that repel water, oils and other undesirable elements to better protect surfaces, create new capabilities and make life better.

New nano-coatings can give painted metals, plastics and other materials super hydrophobic, oleophobic and even antistatic properties.   Imagine a car exterior or interior that repels water and oils making cleanup faster and easier.  That means it stays cleaner longer, uses less soap or detergents and requires less scrubbing or washing.  What if this “miracle coating” was permanent or lasted for years?   That would save a lot of time and money and be a whole lot better for the environment!

With billions of cars on the road, this is a BIG deal and the industry is taking off.  Nano-coatings when applied properly, put a very thin, typically clear or invisible layer that molecularly bonds to the substrate, e.g. painted metals, plastic, fabric, etc.  For car exteriors, silicone dioxide and ceramic blends are becoming popular due to the hardness and heat resistance.  The value of the hardness can tend to be overstated though.  Any material can scratch when scraped against a similarly hard material or hit with enough impact.  Clear coatings are mostly silicone dioxide or some type of clear substance with other “hardeners” added.  They are not 100% ceramic or even diamond for that matter, else they would be opaque (not clear). So, a small rock can certainly scratch the coating or dent the underlying paint and metal.  BUT, it will certainly reduce the scratches, depending on the materials and concentrations in the coating.  Where the hardness will be most beneficial is protecting against everyday use like fingernail scratches at the door handles and cloth scratches from washing or drying.  Even soft sponges trap dirt.  Unlike waxes, swirl marks should be a thing of the past as buffing is no longer necessary.

The biggest benefit comes from the hydrophobic properties of the nano-coating.  The ability to repel water or oils or other dirt elements keeps the surface cleaner, longer.  And when cleanup is needed, it’s a lot easier as the water droplets have less surface area in contact with the surface meaning less hard calcium buildup and less dirt to clean.  That means, fewer chemicals, milder, more sustainable soaps, less scrubbing and fewer scratches wearing down the paint.  Essentially and a much longer lasting beautiful shine without the hassles.  Best of all, nano-coatings are inexpensive.  Some even last for years as opposed to weeks or months like waxes and sealers.  At the low cost, there’s really no reason not to add nano-coatings to protect your investments.

PermaClean Auto 9H is a unique silicone/ceramic hybrid polymer nano-technology that is hard, but provides added elasticity.  It does not require special applicators as it can be sprayed or wiped on in minutes by any consumer.  It dries in 5 minutes and cures in 24 hours (faster under heat lamps).  It has a special benefit of adding temperature resistance up to 500C (932F) and UV protection to save your investment from baking in the sun.  It’s highly durable and has been tested to last for 5-6 years.  Of course, treating a new car or having the paint re-conditioned by a pro before hand is ideal.  3fficient recently launched an entire line of specialty nano-coatings that add amazing properties to everyday surfaces like windows that reject solar heat, kitchens that reject bacteria, fabrics that reject spills and cars that stay cleaner longer.

Important note.  When comparing products, remember to compare features and durability first.  When comparing price, always calculate the cost per coverage area ($/SF) and how long it will last – not the cost per ounce or bottle.  Some cheaper products don’t last very long and many are very expensive for the limited area they cover.

How to plug those (energy) holes in your building

Taking an infrared thermograph of an air conditioned building in the daytime, can be quite alarming. Infrared thermography is the same technology in night vision goggles used by military special forces. It reveals the infrared light spectrum or “heat signature” of objects. On buildings, it reveals variations in heat flow.  The more heat flow the brighter the image.  Windows and skylights, being the least insulated are usually the biggest culprits of energy waste.  For the last 100+ years, heating and air conditioning systems have compensated or covered up the wasted energy flowing through windows and skylights.  But with high energy costs and power plant pollution, that veil is starting to be removed.

Over the last 30 years of my career, I’ve assessed energy efficiency at hundreds of buildings – schools, offices, hospitals, industrials, you name it.  The one thing they all have in common – “energy holes”.   Heat pouring into or out of “closed” windows and skylights.  That heat flow, seen through infrared thermography, translates to wasted energy and unnecessarily BIG electric bills for cooling and increased gas bills for heating.   It also means wasted capital on oversized air conditioning units.  With energy costs the first or second largest expense in most every organization’s budget, why is this still so?  Here’s the typical answers:

  1. “My windows are too expensive to replace.”
  2. “Window tint darkens the room so I’m forced to turn the lights on during the day.”
  3. “Adding tint makes my “window” a mirror at night – I can’t see out but everyone else can see in.”

Before responding, let’s first take stock in what a window is supposed to do:

  1. Let visible light through, so “free” natural light can come in and people can see outside.
  2. Insulate the building, i.e. block heat flow in or out.
  3. Block outside noise.
  4. Block UV rays to protect your carpet, furnishings and skin.
  5. Minimize glare from direct sunlight.

So, again, why are windows not more efficient?

New buildings are usually designed to meet minimum code requirements to keeps costs down.  So, “expensive” products like triple pane, low-emissivity, gas filled windows are rarely considered.  And until construction techniques change dramatically, window replacement will remain costly due to the time and labor required to replace them.  As a result, the energy savings payback for window replacements is usually way too long compared to other options or priorities.

Fortunately, repairs and upgrades of existing windows is very cost effective.  Air infiltration and to a lesser extent noise infiltration can be reduced with simple caulking and weatherstripping repairs.  But, if your window frame is in poor shape or your building is next to a noisy airport or street,  heavy shutters, blinds, double or triple pane windows may be your only option.  When it comes to the main part of the fenestration, the glass or plastic (in the case of skylights), recent material breakthroughs in nanotechnology are revealing some very promising results to reduce solar heat gains.

Before explaining, it’s helpful to understand some physics.

The first law of thermodynamics states, “energy is neither created nor destroyed, it simply changes form”, e.g. heat, light, sound.  In simple terms, the sun is a hot ball that radiates energy (in the form of light) to the earth which then heats up the earth.  After being filtered through the atmosphere, sunlight reaches the earth’s surface as ultraviolet light, visible light and infrared light.  See image below.  Ultraviolet (UV) light is invisible but we see the damaging effects in faded carpets and furnishings or worse – skin cancer.  Visible light (daylight) is the rainbow of colors we see with our eyes.  Infrared light is the intense heat we feel when directly exposed to the sun, e.g. when we come out of the shade or a cloud suddenly moves away.

When it comes to windows, the goal is to block all the UV light, let most or all of the visible light through and block or selectively control the infrared light.  Here’s why.

When the sun’s light hits a window, some is reflected off and some is absorbed by the glass (which can then be directed into, or away from, the interior space) and some passes directly through.  For plastic windows and skylights, much of the UV is blocked, little is absorbed by the material, but most of the infrared light passes right through into the space as heat.

Heat is transferred in three ways: conduction, convection and radiation:

  • Conduction is heat transferred between two objects when they touch – such as when you touch a hot skillet or a warm window.
  • Convection is the flow of a fluid like warm or hot air rising as it is heated up, e.g. when you lean down and open the door of a hot oven and feel the rush of hot air hit your face or sit next to a hot window and feel the heat. Likewise, a large window or door can feel “drafty” as air rises up even though it’s not “leaking from outside.  So, take this into consideration if this is causing you to consider replacement windows.
  • Radiation is light energy heating up an object.  For example, when you step into the sunlight you can feel the sun’s radiant energy on your skin as your skin cells absorb the sun’s radiance.

For cooler climates (i.e. far northern or far southern hemisphere), it is ideal to allow the infrared heat in during the winter, but block as much as possible the rest of the year to reduce cooling loads.   For warmer climates, where most buildings are located, cooling costs usually dominate, so reducing solar heat gain usually dominates decision making.  But, maximizing natural light (without glare) is almost always desired.

So, how do we better manage or reduce solar heat gain?

Overhangs, awnings, light shelves and best of all, deciduous shade trees can help let in the winter sun and block the summer sun.  Unfortunately, they aren’t always practical and were not considered in the vast majority of buildings in existence today.  Clerestories are usually better than traditional skylights, but they are significantly more expensive and rarely used as well.  Then, there are interior window treatments and window coatings.  Interior treatments like shade screens and blinds can help stop the heat, but isn’t the whole purpose of a window to be able to see through it or let the natural light in?  That leaves coatings and tints.

Aftermarket coatings.

  • If your goal is to block out the visible light, then any dark tint will do.
  • If your goal is to block out the light and the heat, then a broad spectrum dark tint will help.  But even that is limited.  Dark curtains, shades or even plywood will actually work better.
  • However, If your goal is to block out just the UV light and the most or all of the infrared heat while letting the VISIBLE light come through, then new nano technologies, are your best bet.

A couple notable options:

Traditional glue-on window films.  Eastman V-Kool 70, Enerlogic 70 and Hi-Lite 70 are high quality plastic films that preform very well. They each block 99% of UV rays and up to 94% of infrared heat while only allowing about 60% of visible light in.  Unfortunately, blocking 30-40% of light still means the interior lights will need to be turned on to compensate.  The materials are relatively expensive and worse yet, they all tend to crack, chip or peel over time.  If applied poorly they will bubble.

Now the game changer…

Liquid window insulation is a spectrally selective paint-on, high performance nanotechnology coating. Nano coatings are a breakthrough because the particles are so small they are invisible to the human eye while adding the desired properties to the coating.  With the small size, the molecules won’t change the optics of the visible light, but are arranged to selectively block out other desired wavelengths.  Due to its application method, it is virtually impossible for liquid nano-tech coatings to bubble, chip, crack or peel.

Available “tints” are 4%, 10% and 16% opacities.  The 4% version is virtually invisible and so clear that it can legally be used on automotive windshields*.  The 16% version has better thermal properties and a slight visible tint to help reduce glare.  The new 10% opacity is a popular “blend of the two which helps cut glare a bit, although not as much as traditional plastic window films. Like the expensive films above, liquid window insulation can block 99% of UV radiation.  But unlike the (now) old tech, liquid window insulation allows 84% – 96% of visible light in while blocking 85% – 97% of infrared heat.  The more opaque, the more infrared heat is blocked.

Liquid window insulation has outstanding performance for most applications.  Perhaps the most important metric for window films in modern “green” building design is the light to solar heat gain ratio (LSG), the LSG ratio provides a gauge of the relative efficiency of different glazing systems in transmitting daylight while blocking solar heat gains.  The higher the ratio, the brighter the room is without adding excessive amounts of heat.

The following chart is a compilation of (lab and NFRC) spectrometer test data. For a spectrally selective solar control film or coating, the LSG ratio will typically be higher than 1.2, while for other films, the LSG ratio will be smaller than 1.0.  The LSG ratio for liquid window insulation is superior to other high end films.

How to read the chart above:

  • Tint.  The opacity or percentage of natural (visible) daylight being blocked.  The lower the percentage the better, unless your goal is to darken the space. Keep in mind, dark plastic films tend to be reflective at night, blocking the view out at night.
  • Visible light Transmission is directly related to tint.  The higher the percentage the better.
  • UV rejection is the % of damaging UltraViolet rays being blocked.  The higher the percentage the better.
  • IR rejection is the % of infrared heat from the sun being blocked.  For warmer climates that need cooling, the higher the percentage better.
  • SHGC is the % of solar heat entering the space. For warmer climates that need cooling, the lower the percentage better.
  • LSG is the ratio of Visible Light Transmission over Solar Heat Gain (VT/SHGC) which measure overall efficiency of a window or skylight coating.  The higher the percentage the better.

The Solar Heat Gain Coefficient (solar efficiency) of new (dual pane low-e) assemblies ranges from 0.41 – 0.60.  However, with daily thermal and UV aging, the soft rubber seals harden and decay, allowing the inert gas between the panes to leak out over time.  As a result, the thermal efficiency is dramatically reduced, leaving the SHGC higher (less efficient) than the even the single pane NanoTint coated alternative.

To take this analysis a step further, we made up our own field test boxes with the front face all glass and faced them directly into the sun.  The results below show the mostly transparent (16%) coating matching dark “limo” tint with solar incidence at 90 degrees, but as time passed and the sun angle became less direct, the nano coating far outperformed even the darkest of traditional tints.  Since the sun is rarely at a right angle to any glass surface, one would expect the liquid window insulation to lead the pack in cumulative energy savings and comfort, such as in a vehicle or next to a window.

I think one of the most compelling applications for liquid window insulation is on skylights.  Skylights are great at bringing in natural light deep inside a building, but the side effect is a lot of unwanted solar heat gain.  Most are plastic, curved and very difficult to apply plastic films to.  This is where liquid window insulation really shines (pun intended).  Getting traditional film on an overhead skylight is very challenging.  If it’s curved plastic, it’s almost impossible.  Liquid window insulation, on the other hand, just rolls on with a special paint roller.  For opaque skylights, it can even be sprayed on.  UV rays will be blocked out and direct infrared heat dramatically reduced.

With better durability, longevity and costs at or below cheaper dark films, the liquid window insulation is a far superior value in comfort, durability, aesthetics, thermal performance, first cost and lifecycle cost.  In terms of  window “upgrades” any of the above films are good, but the liquid window insulation seems to be a consistently better in all areas.

For a more information on installation, click here.


  1. LBNL Fenestration Heat Transfer Basics
  2. DOE Energy Performance Ratings for Windows, Doors and Skylights
  3. Nano particle coatings and applications in window film, DeMeyer

*Note.  Always confirm with local vehicle code and/or enforcement authorities to ensure code compliance.