Solar water heater

Using the heat of the sun in a country where it shines so much and with so much passion it just feels like it would be a shame not to. And then there's the financial consideration: heating water with electricity from the Costa Rican Instituto de Electricidad (ICE) is getting more and more expensive and solar powered water heating can mean real savings in short timescales. It's not the best photo ever taken of a solar water-heater but you get the idea - it's a tank and solar collector mounted on our roof. See the Purasol website for more photos of solar hot water systems in Costa Rica.

The tank holds 160 liters of water, which is perfect for our small family of three for most of the year.

• December - March: 8-10 hours of direct sunshine. Water temperature regularly reaches 80-90 degrees celsius (25-30 farenheit)
• April - July: 6-8 hours of sunshine. The water is still hot enough to have a shower in the afternoon or evening after a day working in the garden! Depending on how much we use, it's common to find the temperature reach 50-70 degrees.
• August - November: This is the wettest part of the year and also the time with the least sunshine. On a bad day there could be only 4 hours sunlight. Unaided the temperature of the water in the tank would not go above 50 degrees but with the electrical back up the temperature is fine.

Purasol standard fit their tanks with a fairly low watt electrical element. This means that even when you do need to use it, the amount of electricity you consume is relativley low and unlikely to make a big difference to your electricity bill. Our bill varies between 10,000 and 15,000 colones per month: $20-$30.

Just to be clear: a solar hot water heater does not generate electricity, it just heats water, which means you don't have to use as much electricity to do so.
After spending a long time talking to Pierre at Purasol, both before and after the installation, I am convinced it was the best solar water heating system for our house. Purasol are located in the same region so it was easy for Pierre to visit and discuss the orientation of the panel (to make best use of the morning sun), do the installation and check everything was working correctly. I also think that the Purasol design is the best available in Costa Rica.

From what I read, the solar tube collectors are the most efficient type of solar water heating system currently available. I think they are particularly suitable for the climate where we are: they heat the water even when we get cloudy days.