I don't know what your weather is like in Houston, but I suspect that it is warmer than what I have here. Where I live, the average daily high temperature year-round ranges from 76 degrees to 86 degrees. In other words, it almost always gets up into the 70s during the day, rarely into the 90s. At night it drops down into the 60s and 70s, rarely into the high 50s. When the temperature gets into the 60s, people walk around wearing parkas with the hoods up, and their dogs are wearing fleece vests. Really.

I can tell you that on a day this week when the temperature never reached 80 degrees, the next morning I had 130 liters of water at a measured temperature of 154 degrees. That considerably outstrips the performance of my dual-burner "tankless" [it actually keeps 10 liters of hot water per burner] gas heater which is rated as being sufficient for a house with two and a half bathrooms.

I am now in the position of using gas only for cooking, and I actually do most of my cooking out on the deck with my barbeque grill. I may never have to fill my roof tank again, and I had been spending about $900 USD per year there.

The cost of the heater itself was $10,800 pesos. An additional $2,200 pesos was required for water pipe and connecting fittings to plumb it into the existing system. I don't know what the installation labor will be, but probably in the vicinity of $3,000 pesos, so total cost is $16,000 pesos. That sounds like a lot, but at present exchange rate, that's an even $1,000 USD.

One downside to the solar heater is that the logical place to mount it is on your roof using about a five foot by eight foot piece of real estate. That means that your hot water tank may end up a long ways away from your faucets, and you'll be sending a good bit of cool water down the drain while you are waiting for the hot water to arrive. In my house, it is 40 seconds to start a hot shower, 50 seconds to get hot water in the kitchen sink.

The technology of the heater is interesting. The tubes are double wall glass with a vacuum between them, and a copper core in the middle to transfer the heat to the storage tank. No water circulates through the tubes. Even though the tank is full of 150 degree water, the tubes are actually cold to the touch, noticeably cooler than ambient air temperature.

So, would I recommend my solar heater to others? Unreservedly, if you live in a climate that will support it. No moving parts, no heating elements, no maintenance. It just sits there and makes hot water. For free.

tanstaafl.