I am constantly annoyed by the ignorance displayed by those pontificating about "solar heating" (Letters, 20 February, page 22).

Someone needs to lay out precisely what is, and what is not, achievable with solar water heating. Since I spent two-and-a-half years as customer liaison manager for one of the leading solar heating firms in the UK, I think that I can put some myths to rest:

  • solar power will not run central heating, but by supplying pre-heated water it will make your current heating cheaper to run
  • it will work anywhere in the UK, even the Scottish islands, but in winter the gain will be reduced the further north you go due to shorter hours of daylight. Conversely, in summer you get much more gain so don't be fooled by an average figure as it could well be heavily distorted
  • users need to take account of how they intend to use solar heating and the size of the household. For example, it's great for a swimming pool but it will struggle to supply the needs of a household of five people, except in summer – although a larger array of solar collectors could supply their needs even in winter, in summer you would probably be able to run a steam boiler
  • it will give solar gain in cloudy conditions since it relies on infrared light, which can penetrate quite a lot of cloud cover. There have been reports of solar gain during rain and falling snow.

The main problem of solar water heating, however, is of course the cost. Why is it so costly? The answer is dead simple, really.

It's a niche market and, as such, occupied by firms that are out to maximise profits. Most of the cost is made up by advertising and salesmen's commission, with a generous profit margin thrown in for good measure.