What can you make with old plastic bottles? A vase? A flowerpot? … an air-conditioning unit? Believe it or not, you can. When inventor Ashis Paul came up with an innovative way to draw cool air into homes using plastic bottles, his whole company got on board to help teach people living in rural Bangledesh to do the same. Since February this year, they’ve helped people to install these units-- which don’t need electricity to function-- in more than 25,000 households in developing areas of the country.

“Most people live in tin huts… in the summer, it’s like being in sauna in the Sahara”


Jaiyyanul Huq is a creative director with the Grey Group, the advertising company that spearheaded this social project.

We are a flood-prone nation, so in rural Bangladesh, most people build their homes out of tin, instead of mud. About 70% of Bangladesh's population lives in these homes. But the problem with these tin huts is that they get unbearably hot in the summer, especially in northern and central Bangladesh. I’ve been in these huts. It’s like being in a sauna in the Sahara.

One of our creative supervisors, Ashis Paul, started thinking about ways to bring relief to these people. He was turning it over in his mind when one day, he overheard his daughter’s physics tutor explaining to her how gas cools when it expands quickly. Ashis has an "inventor" mentality and he’s always been fascinated by science. So, he started experimenting.

He told us about his idea of making an air-conditioner out of plastic bottles. The simplicity of the Eco-Cooler is incredible.

Ashis Paul designed the Eco cooler. 

How to Make an Eco-Cooler


To make an Eco-Cooler, you cut plastic bottles in half and then mount them on a board.


Then, you place the board over a window, with the bottlenecks facing towards the inside of the house.


The change in pressure that occurs when air enters the wider part of the bottle and comes out through the bottleneck cools the air.

It seems uncanny, but the principle is simple. Blow on your hand with your mouth wide open. The air feels hot, doesn’t it? Now, blow on your hand with your lips pursed. It feels like a cool breeze.

The Eco-Cooler doesn’t require any electricity to function!


"We finalised it just as the weather was getting hot"

The Eco-Cooler can decrease the temperature by 5°C immediately. When it goes from 30°C to 25°C, I can tell you that it makes a difference.

The Grey group decided to take it on as a pro-bono project. We like to give back -- it’s core to our company. We decided to make and distribute these units for free. We designed the first prototype in March last year and finally finalised it at the end of February this year. That’s just when the weather starts getting hot in Bangladesh.

“The streets here are littered with bottles, so the raw materials are easy to find”

To distribute the Eco-Coolers, we teamed up with Grameen Intel Social Business Ltd. because they work in a lot of villages in Bangladesh [Editor’s note: Grameen Intel is social business platform that’s a partnership between NGO Grameen and the company Intel]. We sent our teams out to the villages where Grameen Intel works to teach people how to make our Eco-Coolers.


The beauty of it all is how easy these units are to make. First of all, the raw materials are easy to find: people don’t recycle here, so the streets are littered with bottles. We show people how to make them and then ask them to both do it on their own and to teach others. We also made a how-to pdf that’s up on our website and includes an easy step-by-step process.

It’s free and people get immediate results!