[puranjay]

My parents live in a part of India where summer temperatures routinely hit 45C (113F). Because electricity is expensive and my parents' house is quite large, they couldn't afford to run air-conditioning for more than 8-10 hours a day - usually at night.

Whenever I would go home, the heat would completely wreck my productivity. I would have to sequester myself in the coolest room in the house, then judiciously use the air conditioning to maintain some semblance of sanity.

Then my dad got fed up and took advantage of a government subsidy to buy solar panels.

It was expensive initially, but now we essentially have free power. We'll break even in terms of costs within 4 years.

We now run air conditioning when we want, wherever we want.

The increase in productivity is massive. I no longer have to deal with heat when I go home.

Now imagine this happening for billions of people living in tropical climates.

It's going to change the contour of the world

[eru]

> We'll break even in terms of costs within 4 years.

That means a loan of up to 25% interest could have financed the solar panels. Are interest rates higher than that for your parents?

> The increase in productivity is massive. I no longer have to deal with heat when I go home. > Now imagine this happening for billions of people living in tropical climates

For what it's worth, the GDP per capita of Singapore used to track the introduction of air conditioning. Not sure what's cause and what's effect, or coincidence.