I noticed a significant year-on-year increase in the amount of solar panels during my last car trip across Thailand, so I started wondering if going solar is finally became economically viable. Spoiler: it is, but there are some caveats. A 3 kW solar system without battery would cost you about $3,500, and it can cover about 35% of a total power consumption assuming you live in a small house with 3 air-cons, and you work from home so at least one or two of them are always on. For a bigger house, 5 kW system might be more appropriate, and it would cost you about $5,000.

Producing more energy than you consume is currently pointless because the odds are that your energy company won’t buy it from you, so you need to store your extra energy somewhere. Batteries are very expensive, so I won’t even consider this route. My house consumes about 1,000 kW/h of electricity monthly, so a 3 kW solar system is expected to cut my bill by 350 kW/h. Assuming $0.12 per kW/h tariff, the monthly savings would amount to $42, so such a system would pay off in about 7 years. Your mileage may vary, but that seems to be the more or less realistic expectation. It would also be wise to add solar panel maintenance cost (cleaning), which is about $100+ a year.

So, the solar is great and promising, but it’s still pretty expensive. I don’t see a reason to switch to solar now, but I hope it will get cheaper in the future. The price of solar panels has decreased dramatically in the last few years, continuing a decades-long trend.