Air Force-funded white paint could replace air conditioning

Indulge me for a moment. My wife and I recently bought a house in Buffalo, New York. And now, even in Buffalo, it's getting hot enough that we need air conditioning. That costs about $5,000, according to local searches and our first quotes, significantly more than the $30-40 per gallon it would cost to paint our roof with Purdue University's new paint.

Yes, paint. Purdue has been researching a paint that reflects and scatters most light energy, much, much more effectively than all other paint on the market, so much so that it makes buildings cooler than the outside air, in certain conditions by six to eight degrees Fahrenheit.

The Air Force helped fund the original research, which makes a lot of sense when you really think about the Air Force's infrastructure needs. My wife and I need to cool about 1,500 square feet so we'll be more comfortable and productive. The Air Force needs to cool 32,000 square feet per hangar to keep the B-2 Spirit's paint from flaking off. If they fail, pilots die in contested air space and $2 billion aircraft are lost.

Xiulin Ruan, a Purdue University professor of mechanical engineering, led the effort to develop the paint. The paint originally garnered a lot of buzz in 2020-2021, and now it's back as the paint gets closer to store shelves. Even better, the Purdue team and private sector partners have worked on new versions of it. These include new colors and versions that work on aircraft or cars.

(Interestingly, the Air Force used to use white paint on nuclear-armed bombers to reduce radiation damage to the crew.)

The best reflective paints currently on the market still absorb 10 to 20% of the energy from the sun's rays, but the white paint from Ruan only absorbs 1.9%. The new colors absorb slightly more, but still less than 10%.

The secret to the paint is a high concentration of barium sulfate. Different sizes of barium sulfate reflect different wavelengths of light. Ruan and his team made their paint with 60% barium sulfate and mixed different sizes, resulting in a paint so reflective The Guinness Book of World Records came calling.

Surfaces painted with the paint register up to 8 degrees cooler during the day and 19 degrees cooler at night than the ambient air. And since the paint scatters the light it reflects, it's not blinding. Researchers say it looks like completely normal white paint once its applied.

For folks in Buffalo, that could be enough to forego air conditioning altogether. In cities like Phoenix, Arizona, it would drastically reduce air conditioning costs during the summer. It also reduces the heat island effect of cities, meaning that painting a large share of roofs somewhere like Phoenix could make the whole city noticeably cooler.

For the military, it would reduce the air conditioning needs for most of the 750 American installations worldwide. That has greater strategic than fiscal impact, too. Anyone who ever rolled with convoys in Iraq or Afghanistan can tell you how vulnerable the fuel trucks were as well as how often it was fuel logistics that dictated the tempo of convoys.

Modern command centers need at least a little air conditioning to keep the computers working. Some radar and other electronic systems are temperature sensitive, as well. Add the fuel consumption of the radar to the fuel consumption of the machinery cooling it, and you quickly increase the total number of convoys you have to run.

Less A/C needed means less fuel needed means less convoys means less vulnerable fuel trucks getting blown up on convoys.

But of course, in a warming world, everyone wants a little passive cooling, hence the interest from the private sector in Purdue's research. It would be great if you left a baseball game and your car was cooler than the parking lot, right? Or even better if the stadium and the parking lot had reflective paint so the whole area wasn't hotter than Satan's backdoor on wings night?

This Air Force white paint could make offices, homes, cars, stadiums, and so on much more comfortable. And, combined with homegrown energy solutions like American-made solar panels and windmills, nuclear reactors, and hydrogen generation, it could help us reduce our dependence on OPEC.