The young guys installing the system a couple of weeks ago guaranteed hot water even on the coldest of winter days. On the financial side our "four-person" solar water heater cost 3,500 yuan ($527), about the same as a high-end electric water heater, but the comparisons end there. Even with the occasional push of the "add heat" button the installers claim power and maintenance costs shouldn't be much more than 20 yuan a year.

Within four years we will have recouped our equipment costs when compared to the cost of running an electric powered hot water heater, which is estimated at 1,000 yuan annually.

It's no wonder rooftop water heaters are becoming ubiquitous in Beijing. Our bright young installer told me his company has installed 2 million solar water heaters in Beijing since zoning restrictions were eased just over a year ago.

Yet despite it being the obvious right thing to do, most of my neighbours are complaining and fail to see it as a rare opportunity to take individual responsibility.

Management's explanation to residents, which was posted on the door of every house and apartment building, never broached the subject of the environment.

While management wouldn't tell me how much coal it is likely to save by not providing hot water, the 10,000 tons of coal in the packed power plant's yard represents only about 60 percent of what was used last year for both heating and hot water.

The dozen mounds of coal, each bigger than a house, also beg the question: When will the boilers be switched to gas?

This would be a huge score for emission reductions but it seems far off. The power plant manager says coal-fired heating costs residents 19 yuan per square meter per year while central heating powered by gas would cost 30 yuan per square meter per year.

There is also only one gas pipeline into the community, which could be turned off, as happened to one nearby community in the dead of winter.

Although it feels good to have the opportunity to make the right choice, the renewable energy revolution is more than hot showers.

The author is the founder of R.D. Communications. billsiggins@realdogcomm.cn