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I coated my composite roof with a white roof coating. The effect was immediate. A roof that was scorching hot to touch became cool to the touch. It really did reflect the heat ... BUT ... I live in a dirty city. If you look at my roof today, it is no longer white. It is somewhere between off white and dirty grey. Hosing it down does very little to improve it. I think it is still a good idea to paint city roofs white, but I question the value of high tech paint if it is only going to get dirty in a matter of months (or weeks). When I installed solar hot water, I didn't get the super efficient solar panels because all the panels work when the sun is out and don't when it is cloudy or overcast. The efficiency of the panels were not that important. If it was hot when I got into my car, I had hot water in the house. If not, then not ... a higher efficiency panel would not change that. I can't speak to the exterior walls of a home. High tech paint may make a difference. But I think the above experience applies to roof coating. If I had to do it again, I would still coat my roof with the same white roofing material if it were more cost effective than a high tech equivalent; either way, it will be "grey" in no time from the pollution falling out of the city sky. Something to think about.

Living in Thailand we painted the walls bright white and used a bright white steel roof. Our aircon units powered by solar are only 8,500 BTU

This on the heels of the blackest automotive paint ever being created. I'm thinking white roofs and black walls. High sun gets reflected in summer and low sun gets absorbed in winter. There's got to be some ideal geometry to it, based on latitude. Factor it into an overall passive solar solution. Similar to trees shading your house in summer and being leafless in winter. Multiple overlapping solutions providing a year-round benefit. There may be literal grey areas too. ;) Time to conduct some experiments! 🤔 Hold my beer. 🍺🇺🇸

How about colour changing paint, that changes based on "Temperature". White during the hot sunny day and black during the cold or cooler evening.

Stick it on screens that can be rolled up in winter? Houses that adapt to the seasons should be more common by now.

This was my science fair project in middle school. I made tiny houses and painted some in reflective white roof coatings and compared the delta T

Thanks for another great video. Louvers come to mind. One side white and the other side black. Summer expose white and winter expose black. Maybe awnings over windows and doors made of louvers. Lots of possibilities.

Material scientists need to develop a temperature sensitive version. When warmer its whiter & more reflective, then as it gets colder the paint becomes darker & less reflective. Should stop the winter chilling effect.

Great video, very important topic. People are REALLY dumb. I live in a hot climate, where most people spend a lot of money using plenty of energy on airconditioning, yet the majority of new homes have a dark coloured roof, often charcoal or even black- ABSOLUTELY CRAZY. Even basic white keeps your house and your surrounding environment cooler. We fitted a new white roof to our early ‘70’s house in 2012. The difference in summer cooling cost was dramatic!

Actually, if they did it on louvers set on a roof, it good cool during the summer, and at winter just change their orientation so the light hits a dark roof, adding heat to the home. They have also added a live roof system, growing grass, and flowering plants on an office building. It reduced the cooling cost as well as helped clean the air, as well as reduced the water run off to the sewers.

White paint reduces thermal gain. It doesn't remove humidity. You still need A/C.

I live in a humid tropical area (Queensland) and when replacing my roof, chose white painted metal ('Colourbond zincalume'). Unfortunately, as others before me found, in our climate, this colour invites algal growth, which turns black, so the roof quite quickly turned spotted black, which compromised and negated the hoped-for cooling bonus. The house has no air-conditioning.

So need panels that can flip on the roof, white on one side, black on the other, and water line in the middle so can transfer the 10kW of cooling/heating to indoor radiator/under floor lines as needed.

If you liked this subject, you could do a video on ceramic impregnated paint or ceramic tint.

We already do that here in Florida. It works, sort of. White rooms require pressurewashing often to maintain their reflective qualities. What ever savings gets wiped out by the cost of maintenance.

DIRT . This is a 12 minute video that went over all the facts and pro's while omitting one simple fact that makes 98% white paint practically useless. I imagine that readily available 80% reflective paint is already stretching the cleaning efforts that the regular Joe can put in.

In Japan, car insurance is cheaper if your car is white. There is less deterioration on plastic, rubber, upholstery, etc when the car, inside and out, is cooler.

Get a rollable sheet for your roof- white on one side, black on the other. In summer have the white side up and black side down. The white will reflect the suns energy and the black will absorb heat from the house. In winter, the black will absorb energy from the sun and the white bottom will reflect energy from the house back into it. You can choose what point in spring and fall to roll up the sheet, and unravel it in the opposite direction.

I think this also would work nicely here in finland. We get so little sun light in winter anyway that it really doesnt help with heating. But the benefit in summer is huge

Question is how long can you practically keep it white? Dust and stains would drastically reduce efficiency.

In '87 I bought a ceramic infused white paint for roof cooling/fireproofing an asphalt roof. It was $1000. It applied as a thick goop, rolled out. It was a lot cooler in Sacramento summers, 115 degree, but I sold in '90 to make double the purchase price, so I didn't get my money's worth. Same on the added attic reflective foil/insulation. But I tripled my money 17 years later on a house I bought at the dip in Folsom, CA. The left over white paint really cooled down my garage door in Folsom from untouchable to a little warm. That allowed me to use my garage for a poker party every weekend, 3 tables.

Solar panels are better since they generate electricity, but this paint can cover the areas that don't have panels. Actually instead of painting it on the house directly, having painted, *easily* removable, panels that only are installed during summer could be the best option.

Could see this worked in the south facing side of structures while the shadow side is designed to cool by radiating heat away.

I designed my house as solar passive over 25 years back. I didn't tell the builder who would have put the price up 10% if he knew. The house never needs heating daytime in winter if its 60% sunny. In summer many people on walking in asked if we had air conditioning, on 35 deg C days the house is 26 deg C inside. This was a stupidly simple thing to do for zero cost and I couldn't guess how much it saved me over the years. I did stuff up the colour of the roof dark green! I'm colour blind so let my wife choose all, not realizing the effect 😖

Before retirement I did some spectroscopy testing at my work that calibrated some instruments we were building for NASA Earth Sciences satellites. A very pure white powder packed carefully to a flat surface in a recess in a target panel was one part of that calibration of the spectrometer. I do not recall it being barium sulfate. Another was the coating inside a large internally lit sphere that served as a uniform white light source. It is known as an integration sphere and its opening had to be larger than the angle of acceptance of the spectrometer that might have been that compound. What I found in the laboratory that this spectrometer was located was that reflections off of the other surfaces in that room would poorly influence some of the more sensitive readings. I had to find curtain material to block those reflections that was truly black. There were some commercially made dark room curtains that we had, around the sides but the "white" ceiling tiles were distorting the the uniformity and had to be covered with black cloth. It was then I found that what seems black to our eyes is not necessarily black to that spectrometer. Indeed it had a reddish hue towards the red end of the visible. Many swatches of "black" cloth later and I had found the right combination for absorbing as uniformly as our 'white' targets did the opposite. Thanks for reminding me of the subtleties needed in accurate scientific testing. It is not as simple as it sometimes seems. My first thoughts as you described this paint was, of how quickly the soot from urban air pollution would render it right back to that 90% or less reflective level that is so common with such paints, alas.

This is the reason why painting the world black with asphalt and solar panels on all the roofs is a excellent way of making the earth warmer and warmer. A quick look at Stefan-boltzmanns law and we quickly realize that painting the whole world black would immediately make Earth's average temperature reach 40°c!

In design of HVAC systems, we were taught to treat white surfaces as if they were dark for sizing of the equipment. Reasons: 1) White surfaces get dirty, increasing their heat absorption dramatically, particularly in urban areas. 2) In the future, the owner may decide they like a darker color.

Shading windows from incoming direct sunlight, good insulation including window frames and 2 or 3 layer windows. Having air as insulation between roof and the insulation on the attic, and have that space well ventilated. Solar panels on the roof adds shade for the roof, hence for the rest of the building. Controlled ventilation, where very cold or very hot outside air is tempered before entering the inside of the house (some do it with ducts underground). All these are clever ways to construct a building to need less energy!

first thing that came to mind about this paint is using it on space crafts. I keep hearing they have problems keeping cool under direct sunlight, especially when dealing with cryogenic fuels. paint the hull white or even throw a replaceable white tarp over the tanks.

They're missing a key function of air conditioners. Reducing humidity. In some locations, that's even more important than reducing the temperature.

I live in Malaysia and built a house using passive cooling (high ceilings, under roof air flow, large eaves for shading) but still a couple of months have temps that cause sweat even when sitting. This paint is what I need on my metal roof! The temps you described would take the temp down to 68-80F Just perfect! I'd love to do a test!

For me its kind of like the x files. I want to believe, but ive seen so many energy conservation scams and failures that i will remain skeptical until this is proven in real world conditions.

Did this a few years ago, with one side of the roof covered in solar which shades the roof, and the other that gets indirect sun but still gets hot painted white using ordinary house paint. Here in Australia we've had temperatures up to 49C in summer. I still haven't used my A/C since then, and on a hot summer's day the metal roof feels cool to the touch, whereas before it was burning hot. The only downside, as Two Bit mentions, is that in winter when I want the roof to heat up it doesn't, and this means that damp can sometimes form in parts of the roof cavity from the wet areas and kitchen steam etc. But overall it's a massive plus and I only pay for electricity in winter.

Great but I can imagine how painful anything painted with it would be to look at on a summers day without sunglasses...Even normal white paint hurts my eyes in the Australian summer, might be worth it still though.

I think the best thing for thermal insulation and passive heating/cooling are rooftop gardens and vertical vegetation, that keep you cool during summer by dispersing humidity, and insulated during winter

I live in a white painted building. I fact we had to go for a slightly off white to avoid the blinding glare akin to snow blindness.

Ok for the roofs but not sure about the walls : problem with vertical walls is that most energy reflected by those go to the ground, heating the next house, pedestrians, cars, and streets. Also if the paint reflect some long wavelength infrared it can help keeping in the heating. So it is not all bad for cold climate. In architecture the most important design is the south face of the house, that must reflect high sun of summer and try to get in as much as possible low sun of winter.

Another problem, all that reflected light off all the white surfaces will be blinding. All the bright light everywhere you look will require everyone to use dark sunglasses all the time and people that are light sensitive will need to move up to welding glasses or only travel in low-light/night.

As an ac tech i would like this

My baby done left my Lily pad, my legs were both deep fried. I got the Blues, err Greens... Two Bit da Vinci covers the world of physics. Great stuff.

Oooooh man. Now I know what paint to use in a grow room 😆

I'm a painter (artist) and I've known for decades about the passive warming affects of color. White is less warm than darker shades in, for example, direct sunlight. But actually cooling is pretty crazy - smart people at work here. Thanks for sharing the info.

In Florida, summer cooling is my biggest energy cost. We have lots of sea breeze clouds and wet lands around here. It is low population density, so on the surface it looks like the benefits out weigh the concerns. I will need to repaint in a few years so I hope to be able to try this product.

In the world of sound waves, spaces are modified by absorbers and diffusers. Diffusers reflect sound at varying angles. This paint is a light diffuser.

How much of heat absorbed from sun light is caused by visible light and how much of it is caused by other infrared and uv waves ?

Back in the 90's i used a product PolarSeal Top Security which is a 100% acrylic latex which contained a titanium dioxide at a high pigment volume concentration and achieved excellent results. We are at approx. 12 deg N latitude in the tropics and on a hot day both concrete and sheet metal roofs were cool to touch. Approx. 2-3 deg Celcius cooler than surroundings. It went on at a coverage of 50 sq. ft per gallon and served as a waterproof membrane as well. After 20+ years its still performing well.

You clearly have not seen my legs in the winter, I'll see myself out. :)

You certainly do NOT want that if you have to heat in the winter.

I'm amazed they didn't spray this in the metal Boxes they mount the Solar Cells in.

Even without this amazing paint, we'd do well to paint all of our houses and infrastructure white, or make them out of materials that are naturally white. Even if you live north.

Imagine living next to houses with exterior walls painted with this white paint. The glare would be an issue.

Air conditioners aren't sized based on "BTUs". Kilowatt hours DO convert to BTUs (power × time = energy) since BTUs are a unit of ENERGY. An air - conditioner is sized based on the thermal POWER it can provide. Since power is energy per unit of time (energy ÷ time…or dE(t)/dt to be precise), air conditioners are rated in BTU / (time unit - usually hours) or BTU/hr. Actually, they're usually rated in a unit of power known as a ton (equal to the power required to melt one short ton of ice in a 24 hour period) which is 12,000 btu / hr. So, while your conversion of kWh to BTU is roughly correct (3412 BTU per kWh), your "24,000 BTU" sizing claim on air conditioners isn't. It's 24,000 BTU / HR or 2 tons.

Until It gets dust on it… painting things white definitely helps, but using this paint compared to some other white paint doesn’t matter at all because it’s going to get dusty and dirty etc.

Dang this stuff is cool! 😅 PS. we should shift to white roads after we're done with roofs

Best way to understand climate change is to review temperature and rain data as documented in world wide newspapers from 1900 to 1950 and compare to currently published data. Like Stalin said “Those who vote decide nothing. Those who count the vote decide everything.”

There's no silver bullet to energy efficiency, so we need solutions like this to develop the portfolio of options. Every little bit helps.

Putin's chest 🤣🤣🤣. I wasn't going there but since you did ..... that paint so white it makes Betty White look like James Brown.

There is a house a few streets away from me where a facade is made almost entierly out of black metal cladding but it doesn't need any AC. It's got big overhangs in the first floor and shading on the windows in the second. The metal facade has ventilation gap and then 26cm of grey EPS insolation. The walls and floors are all made out od solid concrete so it takes a lot of energy to heat it up in the summer and because the temperatures drops bellow 20 celsius (68 fahrneheit) at night the house stay nice and cold all throught the day. Because of the big overhangs light never actually shines directly into the house but it bounces off of the enviroment around it.

First - A new white coat for me !

So if the buildings do not absorb heat, it will stay in the air. Is this a good idea, or not? Have a black roof. Absorb the heat with water, and use the hot water for heating at night.

regular 100% silicone roof coating achieves similar effect ( 98% reflected and high thermal emissivity).

But most homes are starting to build with insulated roofs and walls. Metal use an air gap. So the cooling effect won't go through anyways. But maybe for old homes.

But what happens to white-painted buildings that are in areas that get severe winters? Are the buildings much colder inside?

I'd like to see that current initiative in NYC expanded and implemented for all low income households...

For winter, you can take advantage of the different angles of light. If you let light in from the side moreso than the top during winter, and also reflects more light during summer, you can passively cool and heat your house

Back in the late 1970s, after I bought my second home, I painted the exterior white. When summer rolled around, it actually looked pink!

I have a problem with this. It is the assumption that the reflected heat will go into space! It would probably go and heat the air in the atmosphere which would do little to nothing for global warming.

(Before seeing the video even) yup, for the two months before it needs to be cleaned maybe. (After) it does seem pretty cool though!

We own a refrigeration company. I had to watch this. There is to much concrete in our cities and towns. It will help it deflect the rays but it will not make AC obsolete. Give it a try, you will have your AC put in after. Not saying it won't help, but don't be fooled.

How about giving everyone a large tax break for putting a white roof on their house in place of a colored one when it needs to be changed !!!!!!!!!!!!!!!

Putting solar panels on the roof of your home not only produces electricity, but it also shades your house from the rays of the sun.

Here in Brazil, white houses are IMMENSELY cooler in the summer

It works! Plus our house never gets pulled over

Interesting. Good luck getting that past your HOA's

In related news, I accomplished the same thing by spreading out all my old AOL CDs on my roof.

Why not have it change color with the temperature, darker when it's cool as white as it's hot?

Not so sure about this.. depends on what this coat of paint will cost? Perhaps it would just be better to install solar panals on ur roof instead of painting them white?

In Canada we need paint that changes colour with temperature so it’s black in the winter and white in the summer. A new challenge!

This paint will be good for regions where there is no winter season, like tropical & desert areas.

“Putin’s chest” lol 😂 that’s good one!

White only helps if only heat is your issue, like in the south and the southwest. In the majority of the country, there is both cooling and heating, and making things cooler in the winter is not what I want for my home.

I gotta wonder about glare and reflection. Will sunglasses be required to see and will plants withstand the higher brightness?

what makes air conditioning not needed is good house design and siteing!!!!

OMG if you could get this paint on fabric you could have ultra white clothing to keep you cool in hot areas. I love this.

Hmm, This definitely sounds too good to be true! Also if reflecting light was all you needed to do you could use mirrors or silver color whci are even more reflective!

Late in the game here 🐢 just painted ordinary White roofing paint on my galvanized roof. Immediate cooling even without the NASA technology cool paint. Still use the aircon though at middle of the day but that's where the big change happened. The aircon really feels cold now that the room is a few degrees less hot from the white paint. Will install a solar roof fan and indoor ceiling exhaust fan and hopefully no more aircon needed. Everyone in the community using air-conditioning is making the outdoors even hotter 🥵

Try it in Houston, where solar heat gain is not the problem

This most excellent paint increases heating costs in colder climates and seems more suited to regions that heat their homes mildly or not at all.

In my area people think it's so fashionable to have a black roof. I live in a hot climate.

I seen one gallon of paint with 1 oz of microcrystalline borite spheres added have a thermal resistance of r-24 with just one coat in 115 degree heat a painted vinyl siding was 72 degrees I'm certain without a doubt that Starlite was actually someone else's way before he brought it up. Without a last or first name the person I refer to is nicknamed Pops.

I was involved in noni-particle paint Uni of Technology Sydney in 2010.

It's probably not as bad in the winter as it intuitively seems. If a material absorbs very little heat, it has a low emissivity. That also means that when it is warmer than the surroundings it radiates less heat than a material with a higher emissivity. So while this stuff won't absorb as much sunlight in the winter as black paint, it will stay warmer at night than black paint.

Can't wait to loose sight because of this paint in broad daylight 😵‍💫

When it's 115 in the shade, the interior is going to be 96. It doesn't matter how white your paint is.

Definitely has potential. Though 2/3 of this nation get very cold in the winter so will have limited application at first.

Some solar panels can absorb reflected sunlight on the back side of the panel as these panels are semi translucent. So if you paint your roof with this paint that reflects in the IR and shorter wavelength part of the spectrum and have solar panels on your roof, do you get the best of both worlds? In other words the panels make electricity on the front of the panels and the house roof remains cool, and the reflected solar from the white coating adds to more efficiency of the solar panels? I would think having the panels with gaps between them and elevated say 6 inches (15 cms) would keep the IR radiation temperature gain from the panels absorbing solar radiation from heating the backside of the panels. This would also keep snow from building up. Another trick is to paint the last foot of the roof eve a brown color so the ice doesn't build up on the edge of the roof. Snow is really a slow moving fluid on the roof and with a steep enough angle will move to the edge and be melted by the brown paint. The last part of the roof can have a short panel of the metal roof and a rubber insulating layer sandwich so heat is not transferred to the underlying roof. Just a thought...

Just cooler not "more" cooler. Informative video. Thanks

Paint tile and metal roofs in hot, sunny climates with this paint...

Your house will be cooler, but your neighbors house will be warmer from the light reflecting from your house. They will send you the bill for the difference.