Solar Water Heating – I told you so!

When I first started thinking about solar water heating and how to explain and value it, I undertook a thorough research into hot water use in the United Kingdom and in other parts of the world. My research led me to conclude that it was fair to attribute about 27% of the domestic energy used to water heating in the United Kingdom and that water heating accounted for about 7% of the United Kingdom’s carbon dioxide emissions and that these emissions form water heating were around 90% from homes.

I developed a model to show the return on investment based on these statistics and other statistics about indirect savings which happen when you have a solar water heating system.

The brochures and comments that Genersys published are based upon the research that I undertook. They have never been officially challenged but I have been told on a number of occasions by officials that the best statistics on water heating showed around 12% of household energy attributed to it and that my figures were wrong.

This view led to institutions like the Energy Savings Trust publishing what I regard as misleading information about solar water heating, describing it as a lifestyle choice and understating the savings of money and carbon dioxide emissions. The Energy Savings Trust has just rethought their position. They now agree that 5% of UK emissions of carbon dioxide are due to water heating by households and that 30% of household energy is spent heating water.

I told them so several years ago and they never believed me.

However, I think that the Energy Savings Trust will need to re-think their present data. The proportion of energy bills attributable to water heating is rising every year for two main reasons.

  1. Homes are being better insulated, which saves on central heating, which accounts for more than twice the cost of water heating, but as homes become better insulated so the proportion of a bill that is due to water heating increases. Insulation does nothing to save energy on water heating.
  2. People are bathing and showering more. This trend will, in my opinion, continue and the average amount of hot water used by a person per day will rise and rise.

As energy becomes more and more expensive with hidden taxes on it for households and oil and gas prices almost certain to rise, so solar water heating becomes more and more important for the saving of fossil fuel, carbon emissions and money.