I WELCOME the constructive comments made by some of your readers recently that a real solution to the energy debate involves reducing energy wastage.

We can all reduce our heating energy (and bills) by adding another layer of clothing and turning down the thermostats.

However, there are those that believe such things as solar panels are the answer. I think we would have to be really naive to think their installation is for purely green motives.

The government's introduction of feed-in-tariffs was to give us a financial motivation.

Before installing solar panels people look at the financial viability of the scheme over the next 20 years or so.

I would suggest that it's not as rosy as some would suggest.

First, if you spent £10.000 on solar panels, rather than investing the money, you might get a better initial return but at the end of the 20 years the panels would just be scrap, whereas you would still have the money that you invested.

Also, money that is invested can be moved to another fund if interest rates etc, change.

So the cost of the depreciation of the panels must be subtracted from the revenue received.

Second, solar panels are only at their best at the time they were installed.

Some tests are suggesting a 20 per cent deterioration in output (and money!) over time, due to ageing of the cells.

Scientists are working on ways that this ageing can be slowed, perhaps by spraying the panels with silicon.

Third, the solar panels currently in production have not been life tested. Five years' use proves nothing.

We all thought that double-glazing would last 20 years but you are lucky if you get 10!

John Dike

Coldridge